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[ovs-dev,v8] AB bonding: Add "primary" interface concept

Message ID 20200623135010.14199-1-jsquyres@cisco.com
State New
Headers show
Series [ovs-dev,v8] AB bonding: Add "primary" interface concept | expand

Commit Message

Jeff Squyres \(jsquyres\) June 23, 2020, 1:50 p.m. UTC
In AB bonding, if the current active slave becomes disabled, a
replacement slave is arbitrarily picked from the remaining set of
enabled slaves.  This commit adds the concept of a "primary" slave: an
interface that will always be (or become) the current active slave if
it is enabled.

The rationale for this functionality is to allow the designation of a
preferred interface for a given bond.  For example:

1. Bond is created with interfaces p1 (primary) and p2, both enabled.
2. p1 becomes the current active slave (because it was designated as
   the primary).
3. Later, p1 fails/becomes disabled.
4. p2 is chosen to become the current active slave.
5. Later, p1 becomes re-enabled.
6. p1 is chosen to become the current active slave (because it was
   designated as the primary)

Note that p1 becomes the active slave once it becomes re-enabled, even
if nothing has happened to p2.

This "primary" concept exists in Linux kernel network interface
bonding, but did not previously exist in OVS bonding.

Only one primary slave inteface is supported per bond, and is only
supported for active/backup bonding.

The primary slave interface is designated via
"other_config:bond-primary" when creating a bond.

Also, while adding tests for the "primary" concept, make a few small
improvements to the non-primary AB bonding test.

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Tested-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: Greg Rose <gvrose8192@gmail.com>
---
NOTE: Oops, I sent this same patch moments ago, but neglected to mark
      it as "v8"

v8:
- Many style and simplification suggestions from Ilya Maximets
- Rename "primary:" to "active-backup primary:" in ovs-appctl
  bond/show output, and make it always appear (vs. only appearing in
  explicit AB bonding scenarios).
- Properly handle fallback-to-AB-bonding cases
- Use time/warp and OVS_WAIT_UNTIL in the bonding tests to prevent
  races, and a few other improvements to the test quality
- After rebasing patch to head of tree, adjust test output as result
  of changes from other commits.

v7:
- After rebasing patch to head of tree, adjust test output as result
  of changes from 81f71381f.

v6:
- Style: bleep bloop.  Fix use of {}.

v5:
- Handle when bond is reconfigured to remove "bond-primary" config.
- Fix potential flapping between remaining slaves.
- Add a test to re-add a removed primary interface and make sure the
  bond reflects that properly.
- Add a test to remove "bond-primary" config and make sure the bond
  reflects that properly.

v4:
- Style: bleep bloop.  Trim line length below 79 characters.

v3:
- Adjusted print logic for when the primary slave is not attached

v2:
- Added "ovs-vsctl bond/show" label when primary interface is no
  longer enslaved
- Fixed strcmp() usage nits
- Moved "other_config:bond-primary" docs to the "Bonding
  Configuration" group
- Expanded commit message
- Added more test cases (including one for when the primary interface
  is no longer enslaved)

 ofproto/bond.c        |  87 ++++++++++++++--
 ofproto/bond.h        |   1 +
 tests/lacp.at         |   9 ++
 tests/ofproto-dpif.at | 224 +++++++++++++++++++++++++++++++++++++++---
 vswitchd/bridge.c     |   5 +
 vswitchd/vswitch.xml  |   8 ++
 6 files changed, 313 insertions(+), 21 deletions(-)

Comments

Ilya Maximets June 24, 2020, 7:35 p.m. UTC | #1
On 6/23/20 3:50 PM, Jeff Squyres via dev wrote:
> In AB bonding, if the current active slave becomes disabled, a
> replacement slave is arbitrarily picked from the remaining set of
> enabled slaves.  This commit adds the concept of a "primary" slave: an
> interface that will always be (or become) the current active slave if
> it is enabled.
> 
> The rationale for this functionality is to allow the designation of a
> preferred interface for a given bond.  For example:
> 
> 1. Bond is created with interfaces p1 (primary) and p2, both enabled.
> 2. p1 becomes the current active slave (because it was designated as
>    the primary).
> 3. Later, p1 fails/becomes disabled.
> 4. p2 is chosen to become the current active slave.
> 5. Later, p1 becomes re-enabled.
> 6. p1 is chosen to become the current active slave (because it was
>    designated as the primary)
> 
> Note that p1 becomes the active slave once it becomes re-enabled, even
> if nothing has happened to p2.
> 
> This "primary" concept exists in Linux kernel network interface
> bonding, but did not previously exist in OVS bonding.
> 
> Only one primary slave inteface is supported per bond, and is only
> supported for active/backup bonding.
> 
> The primary slave interface is designated via
> "other_config:bond-primary" when creating a bond.
> 
> Also, while adding tests for the "primary" concept, make a few small
> improvements to the non-primary AB bonding test.
> 
> Signed-off-by: Jeff Squyres <jsquyres@cisco.com>
> Reviewed-by: Aaron Conole <aconole@redhat.com>
> Tested-by: Greg Rose <gvrose8192@gmail.com>
> Acked-by: Greg Rose <gvrose8192@gmail.com>
> ---
> NOTE: Oops, I sent this same patch moments ago, but neglected to mark
>       it as "v8"
> 
> v8:
> - Many style and simplification suggestions from Ilya Maximets
> - Rename "primary:" to "active-backup primary:" in ovs-appctl
>   bond/show output, and make it always appear (vs. only appearing in
>   explicit AB bonding scenarios).
> - Properly handle fallback-to-AB-bonding cases
> - Use time/warp and OVS_WAIT_UNTIL in the bonding tests to prevent
>   races, and a few other improvements to the test quality
> - After rebasing patch to head of tree, adjust test output as result
>   of changes from other commits.
> 
> v7:
> - After rebasing patch to head of tree, adjust test output as result
>   of changes from 81f71381f.
> 
> v6:
> - Style: bleep bloop.  Fix use of {}.
> 
> v5:
> - Handle when bond is reconfigured to remove "bond-primary" config.
> - Fix potential flapping between remaining slaves.
> - Add a test to re-add a removed primary interface and make sure the
>   bond reflects that properly.
> - Add a test to remove "bond-primary" config and make sure the bond
>   reflects that properly.
> 
> v4:
> - Style: bleep bloop.  Trim line length below 79 characters.
> 
> v3:
> - Adjusted print logic for when the primary slave is not attached
> 
> v2:
> - Added "ovs-vsctl bond/show" label when primary interface is no
>   longer enslaved
> - Fixed strcmp() usage nits
> - Moved "other_config:bond-primary" docs to the "Bonding
>   Configuration" group
> - Expanded commit message
> - Added more test cases (including one for when the primary interface
>   is no longer enslaved)
> 
>  ofproto/bond.c        |  87 ++++++++++++++--
>  ofproto/bond.h        |   1 +
>  tests/lacp.at         |   9 ++
>  tests/ofproto-dpif.at | 224 +++++++++++++++++++++++++++++++++++++++---
>  vswitchd/bridge.c     |   5 +
>  vswitchd/vswitch.xml  |   8 ++
>  6 files changed, 313 insertions(+), 21 deletions(-)
> 
> diff --git a/ofproto/bond.c b/ofproto/bond.c
> index 9947e7531..4e634e2ce 100644
> --- a/ofproto/bond.c
> +++ b/ofproto/bond.c
> @@ -89,6 +89,7 @@ struct bond_slave {
>      /* Link status. */
>      bool enabled;               /* May be chosen for flows? */
>      bool may_enable;            /* Client considers this slave bondable. */
> +    bool is_primary;            /* This slave is preferred over others. */
>      long long delay_expires;    /* Time after which 'enabled' may change. */
>  
>      /* Rebalancing info.  Used only by bond_rebalance(). */
> @@ -124,6 +125,7 @@ struct bond {
>      uint32_t basis;             /* Basis for flow hash function. */
>      bool use_lb_output_action;  /* Use lb_output action to avoid recirculation.
>                                     Applicable only for Balance TCP mode. */
> +    char *primary;              /* Name of the primary slave interface. */
>  
>      /* SLB specific bonding info. */
>      struct bond_entry *hash;     /* An array of BOND_BUCKETS elements. */
> @@ -241,6 +243,7 @@ bond_create(const struct bond_settings *s, struct ofproto_dpif *ofproto)
>  
>      bond->active_slave_mac = eth_addr_zero;
>      bond->active_slave_changed = false;
> +    bond->primary = NULL;
>  
>      bond_reconfigure(bond, s);
>      return bond;
> @@ -294,6 +297,7 @@ bond_unref(struct bond *bond)
>      update_recirc_rules__(bond);
>  
>      hmap_destroy(&bond->pr_rule_ops);
> +    free(bond->primary);
>      free(bond->name);
>      free(bond);
>  }
> @@ -471,6 +475,45 @@ bond_reconfigure(struct bond *bond, const struct bond_settings *s)
>          bond->bond_revalidate = false;
>      }
>  
> +    /*
> +     * If a primary interface is set on the new settings:
> +     * 1. If the bond has no primary previously set, save it and
> +     * revalidate.
> +     * 2. If the bond has a different primary previously set, save the
> +     * new one and revalidate.
> +     * 3. If the bond has the same primary previously set, do nothing.
> +     */
> +    if (!nullable_string_is_equal(bond->primary, s->primary)) {
> +        free(bond->primary);
> +        bond->primary = nullable_xstrdup(s->primary);
> +        revalidate = true;
> +    }
> +
> +    if (s->primary) {
> +        bool changed = false;
> +        if (bond->primary) {
> +            if (strcmp(bond->primary, s->primary)) {
> +                free(bond->primary);
> +                changed = true;
> +            }
> +        } else {
> +            changed = true;
> +        }
> +
> +        if (changed) {
> +            bond->primary = xstrdup(s->primary);
> +            revalidate = true;
> +        }
> +    } else if (bond->primary) {
> +        /*
> +         * If the new settings have no primary interface, but the
> +         * bond already has a primary, remove the bond's primary.
> +         */
> +        free(bond->primary);
> +        bond->primary = NULL;
> +        revalidate = true;
> +    }
> +

Not a full review, but it looks like you forgt to remove that old code.
And now you're re-allocating things twice.

>      if (bond->balance != BM_AB) {
>          if (!bond->recirc_id) {
>              bond->recirc_id = recirc_alloc_id(bond->ofproto);
> @@ -575,6 +618,12 @@ bond_slave_register(struct bond *bond, void *slave_,
>          slave->name = xstrdup(netdev_get_name(netdev));
>          bond->bond_revalidate = true;
>  
> +        if (bond->primary && !strcmp(bond->primary, slave->name)) {
> +            slave->is_primary = true;
> +        } else {
> +            slave->is_primary = false;
> +        }
> +
>          slave->enabled = false;
>          bond_enable_slave(slave, netdev_get_carrier(netdev));
>      }
> @@ -668,7 +717,7 @@ bond_slave_set_may_enable(struct bond *bond, void *slave_, bool may_enable)
>  bool
>  bond_run(struct bond *bond, enum lacp_status lacp_status)
>  {
> -    struct bond_slave *slave;
> +    struct bond_slave *slave, *primary;
>      bool revalidate;
>  
>      ovs_rwlock_wrlock(&rwlock);
> @@ -685,11 +734,19 @@ bond_run(struct bond *bond, enum lacp_status lacp_status)
>      }
>  
>      /* Enable slaves based on link status and LACP feedback. */
> +    primary = NULL;
>      HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
>          bond_link_status_update(slave);
>          slave->change_seq = seq_read(connectivity_seq_get());
> +
> +        /* Discover if there is an active slave marked 'primary' */

There should be a period at the end of the comment.

> +        if (bond->balance == BM_AB && slave->is_primary && slave->enabled) {
> +            primary = slave;
> +        }
>      }
> -    if (!bond->active_slave || !bond->active_slave->enabled) {
> +
> +    if (!bond->active_slave || !bond->active_slave->enabled ||
> +        (primary && bond->active_slave != primary)) {
>          bond_choose_active_slave(bond);
>      }
>  
> @@ -1437,16 +1494,25 @@ bond_print_details(struct ds *ds, const struct bond *bond)
>      ds_put_format(ds, "lacp_fallback_ab: %s\n",
>                    bond->lacp_fallback_ab ? "true" : "false");
>  
> -    ds_put_cstr(ds, "active slave mac: ");
> -    ds_put_format(ds, ETH_ADDR_FMT, ETH_ADDR_ARGS(bond->active_slave_mac));
> +    bool found_primary = false;
>      slave = bond_find_slave_by_mac(bond, bond->active_slave_mac);
> -    ds_put_format(ds,"(%s)\n", slave ? slave->name : "none");
> -
>      HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
> +        if (slave->is_primary) {
> +            found_primary = true;
> +        }
>          shash_add(&slave_shash, slave->name, slave);
>      }
> -    sorted_slaves = shash_sort(&slave_shash);
>  
> +    ds_put_format(ds, "active-backup primary: %s%s\n",
> +                  bond->primary ? bond->primary : "<none>",
> +                  (!found_primary && bond->primary)
> +                  ? " (no such slave)" : "");
> +
> +    ds_put_cstr(ds, "active slave mac: ");
> +    ds_put_format(ds, ETH_ADDR_FMT, ETH_ADDR_ARGS(bond->active_slave_mac));
> +    ds_put_format(ds,"(%s)\n", slave ? slave->name : "none");
> +
> +    sorted_slaves = shash_sort(&slave_shash);
>      for (i = 0; i < shash_count(&slave_shash); i++) {
>          struct bond_entry *be;
>  
> @@ -1906,6 +1972,13 @@ bond_choose_slave(const struct bond *bond)
>  {
>      struct bond_slave *slave, *best;
>  
> +    /* If there's a primary and it's active, return that. */
> +    HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
> +        if (slave->is_primary && slave->enabled) {
> +            return slave;
> +        }
> +    }
> +
>      /* Find the last active slave. */
>      slave = bond_find_slave_by_mac(bond, bond->active_slave_mac);
>      if (slave && slave->enabled) {
> diff --git a/ofproto/bond.h b/ofproto/bond.h
> index 40c3258dc..1a42a37c9 100644
> --- a/ofproto/bond.h
> +++ b/ofproto/bond.h
> @@ -45,6 +45,7 @@ struct bond_settings {
>  
>      /* Balancing configuration. */
>      enum bond_mode balance;
> +    const char *primary;        /* For AB balance, primary interface name. */
>      int rebalance_interval;     /* Milliseconds between rebalances.
>                                     Zero to disable rebalancing. */
>  
> diff --git a/tests/lacp.at b/tests/lacp.at
> index df1691731..5257f0cce 100644
> --- a/tests/lacp.at
> +++ b/tests/lacp.at
> @@ -126,6 +126,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  active slave mac: 00:00:00:00:00:00(none)
>  
>  slave p1: disabled
> @@ -292,6 +293,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  
>  slave p0: enabled
>    may_enable: true
> @@ -308,6 +310,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  
>  slave p2: enabled
>    may_enable: true
> @@ -431,6 +434,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  <active slave mac del>
>  
>  slave p0: disabled
> @@ -449,6 +453,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  <active slave mac del>
>  
>  slave p2: disabled
> @@ -565,6 +570,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  <active slave mac del>
>  
>  slave p0: disabled
> @@ -583,6 +589,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  <active slave mac del>
>  
>  slave p2: disabled
> @@ -704,6 +711,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  <active slave mac del>
>  
>  slave p0: enabled
> @@ -722,6 +730,7 @@ updelay: 0 ms
>  downdelay: 0 ms
>  lacp_status: negotiated
>  lacp_fallback_ab: false
> +active-backup primary: <none>
>  <active slave mac del>
>  
>  slave p2: enabled
> diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
> index e3402e7b8..808200800 100644
> --- a/tests/ofproto-dpif.at
> +++ b/tests/ofproto-dpif.at
> @@ -29,12 +29,16 @@ AT_CHECK([ovs-appctl revalidator/wait])
>  OVS_VSWITCHD_STOP
>  AT_CLEANUP
>  
> -AT_SETUP([ofproto-dpif - active-backup bonding])
> -# Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and p2
> -#    and br1 with interfaces p3, p4 and p8.
> -# toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
> +AT_SETUP([ofproto-dpif - active-backup bonding (with primary)])
> +
> +dnl Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and
> +dnl    p2 (p1 as primary) and br1 with interfaces p3, p4 and p8.
> +dnl toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
> +dnl With p1 down and p2 up/active, bring p1 back up.  Since p1 is the primary,
> +dnl it should become active.
>  OVS_VSWITCHD_START(
> -  [add-bond br0 bond0 p1 p2 bond_mode=active-backup --\
> +  [add-bond br0 bond0 p1 p2 bond_mode=active-backup \
> +                other_config:bond-primary=p1 -- \
>     set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
>     set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
>     add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy -- \
> @@ -45,9 +49,202 @@ OVS_VSWITCHD_START(
>     add-port br1 p3 -- set interface p3 type=dummy options:stream=unix:$OVS_RUNDIR/p1.sock ofport_request=3 -- \
>     add-port br1 p4 -- set interface p4 type=dummy options:stream=unix:$OVS_RUNDIR/p2.sock ofport_request=4 -- \
>     add-port br1 p8 -- set interface p8 ofport_request=8 type=dummy --])
> +AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
>  WAIT_FOR_DUMMY_PORTS([p3], [p4])
> +OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: p1'`"])
> +
> +
> +AT_CHECK([ovs-ofctl add-flow br0 action=normal])
> +AT_CHECK([ovs-ofctl add-flow br1 action=normal])
> +ovs-appctl netdev-dummy/set-admin-state up
> +ovs-appctl time/warp 100
> +ovs-appctl netdev-dummy/set-admin-state p2 down
> +ovs-appctl time/stop
> +ovs-appctl time/warp 100
> +AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(src=10.0.0.2,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(src=10.0.0.3,dst=10.0.0.4,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +ovs-appctl time/warp 100
> +ovs-appctl netdev-dummy/set-admin-state p2 up
> +ovs-appctl netdev-dummy/set-admin-state p1 down
> +ovs-appctl time/warp 100
> +AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(src=10.0.0.5,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(src=10.0.0.6,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +ovs-appctl time/warp 2000 100
> +AT_CHECK([ovs-appctl dpctl/dump-flows | grep 'in_port([[348]])' | strip_xout], [0], [dnl
> +recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
> +])
> +
> +ovs-appctl netdev-dummy/set-admin-state p1 up
> +ovs-appctl time/warp 100
> +OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
> +---- bond0 ----
> +bond_mode: active-backup
> +bond may use recirculation: no, <del>
> +bond-hash-basis: 0
> +updelay: 0 ms
> +downdelay: 0 ms
> +lacp_status: off
> +lacp_fallback_ab: false
> +active-backup primary: p1
> +<active slave mac del>
> +
> +slave p1: enabled
> +  active slave
> +  may_enable: true
> +
> +slave p2: enabled
> +  may_enable: true
> +
> +])
> +
> +OVS_VSWITCHD_STOP
> +AT_CLEANUP
> +
> +AT_SETUP([ofproto-dpif - active-backup bonding (primary validation)])
> +dnl Make a switch with 3 ports in a bond, so that when we delete one of
> +dnl the ports from the bond, there are still 2 ports left and the bond
> +dnl remains functional.
> +OVS_VSWITCHD_START(
> +  [add-bond br0 bond0 p1 p2 p3 bond_mode=active-backup \
> +                other_config:bond-primary=p1 -- \
> +   set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
> +   set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
> +   set interface p3 type=dummy options:pstream=punix:$OVS_RUNDIR/p3.sock ofport_request=3 -- \
> +   add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy --])
>  AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
>  
> +dnl Make sure the initial primary interface is set
> +OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: p1'`"])
> +
> +dnl Down the primary interface and verify that we switched.  Then
> +dnl bring the primary back and verify that we switched back to the
> +dnl primary.
> +ovs-appctl netdev-dummy/set-admin-state p1 down
> +ovs-appctl time/warp 100
> +OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | fgrep 'slave p1: disabled'`"])
> +ovs-appctl netdev-dummy/set-admin-state p1 up
> +ovs-appctl time/warp 100
> +OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
> +---- bond0 ----
> +bond_mode: active-backup
> +bond may use recirculation: no, <del>
> +bond-hash-basis: 0
> +updelay: 0 ms
> +downdelay: 0 ms
> +lacp_status: off
> +lacp_fallback_ab: false
> +active-backup primary: p1
> +<active slave mac del>
> +
> +slave p1: enabled
> +  active slave
> +  may_enable: true
> +
> +slave p2: enabled
> +  may_enable: true
> +
> +slave p3: enabled
> +  may_enable: true
> +
> +])
> +
> +dnl Now delete the primary and verify that the output shows that the
> +dnl primary is no longer enslaved
> +ovs-vsctl --id=@p1 get Interface p1 -- remove Port bond0 interfaces @p1
> +ovs-appctl time/warp 100
> +OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | fgrep 'active-backup primary: p1 (no such slave)'`"])
> +
> +dnl Now re-add the primary and verify that the output shows that the
> +dnl primary is available again.
> +dnl
> +dnl First, get the UUIDs of the interfaces that exist on bond0.
> +dnl Strip the trailing ] so that we can add a new UUID to the end.
> +uuids=`ovs-vsctl get Port bond0 interfaces | sed -e 's/]//'`
> +dnl Create a new port "p1" and add its UUID to the set of interfaces
> +dnl on bond0.
> +ovs-vsctl \
> +   --id=@p1 create Interface name=p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
> +   set Port bond0 interfaces="$uuids, @p1]"
> +ovs-appctl time/warp 100
> +OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
> +---- bond0 ----
> +bond_mode: active-backup
> +bond may use recirculation: no, <del>
> +bond-hash-basis: 0
> +updelay: 0 ms
> +downdelay: 0 ms
> +lacp_status: off
> +lacp_fallback_ab: false
> +active-backup primary: p1
> +<active slave mac del>
> +
> +slave p1: enabled
> +  active slave
> +  may_enable: true
> +
> +slave p2: enabled
> +  may_enable: true
> +
> +slave p3: enabled
> +  may_enable: true
> +
> +])
> +
> +dnl Remove the "bond-primary" config directive from the bond.
> +AT_CHECK([ovs-vsctl remove Port bond0 other_config bond-primary])
> +ovs-appctl time/warp 100
> +OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
> +---- bond0 ----
> +bond_mode: active-backup
> +bond may use recirculation: no, <del>
> +bond-hash-basis: 0
> +updelay: 0 ms
> +downdelay: 0 ms
> +lacp_status: off
> +lacp_fallback_ab: false
> +active-backup primary: <none>
> +<active slave mac del>
> +
> +slave p1: enabled
> +  active slave
> +  may_enable: true
> +
> +slave p2: enabled
> +  may_enable: true
> +
> +slave p3: enabled
> +  may_enable: true
> +
> +])
> +
> +OVS_VSWITCHD_STOP
> +AT_CLEANUP
> +
> +AT_SETUP([ofproto-dpif - active-backup bonding (without primary)])
> +dnl Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and p2
> +dnl    and br1 with interfaces p3, p4 and p8.
> +dnl toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
> +OVS_VSWITCHD_START(
> +  [add-bond br0 bond0 p1 p2 bond_mode=active-backup --\
> +   set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
> +   set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
> +   add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy -- \
> +   add-br br1 -- \
> +   set bridge br1 other-config:hwaddr=aa:66:aa:66:00:00 -- \
> +   set bridge br1 datapath-type=dummy other-config:datapath-id=1234 \
> +                  fail-mode=secure -- \
> +   add-port br1 p3 -- set interface p3 type=dummy options:stream=unix:$OVS_RUNDIR/p1.sock ofport_request=3 -- \
> +   add-port br1 p4 -- set interface p4 type=dummy options:stream=unix:$OVS_RUNDIR/p2.sock ofport_request=4 -- \
> +   add-port br1 p8 -- set interface p8 ofport_request=8 type=dummy --])
> +AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
> +WAIT_FOR_DUMMY_PORTS([p3], [p4])
> +OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: <none>'`"])
> +
>  AT_CHECK([ovs-ofctl add-flow br0 action=normal])
>  AT_CHECK([ovs-ofctl add-flow br1 action=normal])
>  ovs-appctl netdev-dummy/set-admin-state up
> @@ -63,15 +260,14 @@ ovs-appctl netdev-dummy/set-admin-state p1 down
>  ovs-appctl time/warp 100
>  AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(src=10.0.0.5,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
>  AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(src=10.0.0.6,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> -ovs-appctl time/warp 200 100
> -sleep 1
> -AT_CHECK([grep 'in_port([[348]])' ovs-vswitchd.log | filter_flow_install | strip_xout], [0], [dnl
> -recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), actions: <del>
> -recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), actions: <del>
> -recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), actions: <del>
> -recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), actions: <del>
> -recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), actions: <del>
> -recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), actions: <del>
> +ovs-appctl time/warp 2000 100
> +AT_CHECK([ovs-appctl dpctl/dump-flows | grep 'in_port([[348]])' | strip_xout], [0], [dnl
> +recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
> +recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
>  ])
>  OVS_VSWITCHD_STOP
>  AT_CLEANUP
> diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
> index f312efd8e..7111fbac3 100644
> --- a/vswitchd/bridge.c
> +++ b/vswitchd/bridge.c
> @@ -4563,6 +4563,11 @@ port_configure_bond(struct port *port, struct bond_settings *s)
>                    port->name);
>      }
>  
> +    s->primary = NULL;
> +    if (s->balance == BM_AB || s->lacp_fallback_ab_cfg) {
> +        s->primary = smap_get(&port->cfg->other_config, "bond-primary");
> +    }
> +
>      miimon_interval = smap_get_int(&port->cfg->other_config,
>                                     "bond-miimon-interval", 0);
>      if (miimon_interval <= 0) {
> diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
> index b6acb34ca..944708ed6 100644
> --- a/vswitchd/vswitch.xml
> +++ b/vswitchd/vswitch.xml
> @@ -2003,6 +2003,14 @@
>          This knob does not affect other balancing modes.
>        </column>
>  
> +      <column name="other_config" key="bond-primary"
> +              type='{"type": "string"}'>
> +        If a slave interface with this name exists in the bond and
> +        is up, it will be made active.  Relevant only when <ref
> +        column="other_config" key="bond-mode"/> is
> +        <code>active-backup</code>.
> +      </column>
> +
>        <group title="Link Failure Detection">
>          <p>
>            An important part of link bonding is detecting that links are down so
>
Jeff Squyres \(jsquyres\) June 25, 2020, 8:56 p.m. UTC | #2
On Jun 24, 2020, at 3:35 PM, Ilya Maximets <i.maximets@ovn.org<mailto:i.maximets@ovn.org>> wrote:

On 6/23/20 3:50 PM, Jeff Squyres via dev wrote:
In AB bonding, if the current active slave becomes disabled, a
replacement slave is arbitrarily picked from the remaining set of
enabled slaves.  This commit adds the concept of a "primary" slave: an
interface that will always be (or become) the current active slave if
it is enabled.

The rationale for this functionality is to allow the designation of a
preferred interface for a given bond.  For example:

1. Bond is created with interfaces p1 (primary) and p2, both enabled.
2. p1 becomes the current active slave (because it was designated as
  the primary).
3. Later, p1 fails/becomes disabled.
4. p2 is chosen to become the current active slave.
5. Later, p1 becomes re-enabled.
6. p1 is chosen to become the current active slave (because it was
  designated as the primary)

Note that p1 becomes the active slave once it becomes re-enabled, even
if nothing has happened to p2.

This "primary" concept exists in Linux kernel network interface
bonding, but did not previously exist in OVS bonding.

Only one primary slave inteface is supported per bond, and is only
supported for active/backup bonding.

The primary slave interface is designated via
"other_config:bond-primary" when creating a bond.

Also, while adding tests for the "primary" concept, make a few small
improvements to the non-primary AB bonding test.

Signed-off-by: Jeff Squyres <jsquyres@cisco.com<mailto:jsquyres@cisco.com>>
Reviewed-by: Aaron Conole <aconole@redhat.com<mailto:aconole@redhat.com>>
Tested-by: Greg Rose <gvrose8192@gmail.com<mailto:gvrose8192@gmail.com>>
Acked-by: Greg Rose <gvrose8192@gmail.com<mailto:gvrose8192@gmail.com>>
---
NOTE: Oops, I sent this same patch moments ago, but neglected to mark
     it as "v8"

v8:
- Many style and simplification suggestions from Ilya Maximets
- Rename "primary:" to "active-backup primary:" in ovs-appctl
 bond/show output, and make it always appear (vs. only appearing in
 explicit AB bonding scenarios).
- Properly handle fallback-to-AB-bonding cases
- Use time/warp and OVS_WAIT_UNTIL in the bonding tests to prevent
 races, and a few other improvements to the test quality
- After rebasing patch to head of tree, adjust test output as result
 of changes from other commits.

v7:
- After rebasing patch to head of tree, adjust test output as result
 of changes from 81f71381f.

v6:
- Style: bleep bloop.  Fix use of {}.

v5:
- Handle when bond is reconfigured to remove "bond-primary" config.
- Fix potential flapping between remaining slaves.
- Add a test to re-add a removed primary interface and make sure the
 bond reflects that properly.
- Add a test to remove "bond-primary" config and make sure the bond
 reflects that properly.

v4:
- Style: bleep bloop.  Trim line length below 79 characters.

v3:
- Adjusted print logic for when the primary slave is not attached

v2:
- Added "ovs-vsctl bond/show" label when primary interface is no
 longer enslaved
- Fixed strcmp() usage nits
- Moved "other_config:bond-primary" docs to the "Bonding
 Configuration" group
- Expanded commit message
- Added more test cases (including one for when the primary interface
 is no longer enslaved)

ofproto/bond.c        |  87 ++++++++++++++--
ofproto/bond.h        |   1 +
tests/lacp.at<http://lacp.at>         |   9 ++
tests/ofproto-dpif.at<http://ofproto-dpif.at> | 224 +++++++++++++++++++++++++++++++++++++++---
vswitchd/bridge.c     |   5 +
vswitchd/vswitch.xml  |   8 ++
6 files changed, 313 insertions(+), 21 deletions(-)

diff --git a/ofproto/bond.c b/ofproto/bond.c
index 9947e7531..4e634e2ce 100644
--- a/ofproto/bond.c
+++ b/ofproto/bond.c
@@ -89,6 +89,7 @@ struct bond_slave {
    /* Link status. */
    bool enabled;               /* May be chosen for flows? */
    bool may_enable;            /* Client considers this slave bondable. */
+    bool is_primary;            /* This slave is preferred over others. */
    long long delay_expires;    /* Time after which 'enabled' may change. */

    /* Rebalancing info.  Used only by bond_rebalance(). */
@@ -124,6 +125,7 @@ struct bond {
    uint32_t basis;             /* Basis for flow hash function. */
    bool use_lb_output_action;  /* Use lb_output action to avoid recirculation.
                                   Applicable only for Balance TCP mode. */
+    char *primary;              /* Name of the primary slave interface. */

    /* SLB specific bonding info. */
    struct bond_entry *hash;     /* An array of BOND_BUCKETS elements. */
@@ -241,6 +243,7 @@ bond_create(const struct bond_settings *s, struct ofproto_dpif *ofproto)

    bond->active_slave_mac = eth_addr_zero;
    bond->active_slave_changed = false;
+    bond->primary = NULL;

    bond_reconfigure(bond, s);
    return bond;
@@ -294,6 +297,7 @@ bond_unref(struct bond *bond)
    update_recirc_rules__(bond);

    hmap_destroy(&bond->pr_rule_ops);
+    free(bond->primary);
    free(bond->name);
    free(bond);
}
@@ -471,6 +475,45 @@ bond_reconfigure(struct bond *bond, const struct bond_settings *s)
        bond->bond_revalidate = false;
    }

+    /*
+     * If a primary interface is set on the new settings:
+     * 1. If the bond has no primary previously set, save it and
+     * revalidate.
+     * 2. If the bond has a different primary previously set, save the
+     * new one and revalidate.
+     * 3. If the bond has the same primary previously set, do nothing.
+     */
+    if (!nullable_string_is_equal(bond->primary, s->primary)) {
+        free(bond->primary);
+        bond->primary = nullable_xstrdup(s->primary);
+        revalidate = true;
+    }
+
+    if (s->primary) {
+        bool changed = false;
+        if (bond->primary) {
+            if (strcmp(bond->primary, s->primary)) {
+                free(bond->primary);
+                changed = true;
+            }
+        } else {
+            changed = true;
+        }
+
+        if (changed) {
+            bond->primary = xstrdup(s->primary);
+            revalidate = true;
+        }
+    } else if (bond->primary) {
+        /*
+         * If the new settings have no primary interface, but the
+         * bond already has a primary, remove the bond's primary.
+         */
+        free(bond->primary);
+        bond->primary = NULL;
+        revalidate = true;
+    }
+

Not a full review, but it looks like you forgt to remove that old code.
And now you're re-allocating things twice.

Gah, that's embarrassing.  Fixed.

    if (bond->balance != BM_AB) {
        if (!bond->recirc_id) {
            bond->recirc_id = recirc_alloc_id(bond->ofproto);
@@ -575,6 +618,12 @@ bond_slave_register(struct bond *bond, void *slave_,
        slave->name = xstrdup(netdev_get_name(netdev));
        bond->bond_revalidate = true;

+        if (bond->primary && !strcmp(bond->primary, slave->name)) {
+            slave->is_primary = true;
+        } else {
+            slave->is_primary = false;
+        }
+
        slave->enabled = false;
        bond_enable_slave(slave, netdev_get_carrier(netdev));
    }
@@ -668,7 +717,7 @@ bond_slave_set_may_enable(struct bond *bond, void *slave_, bool may_enable)
bool
bond_run(struct bond *bond, enum lacp_status lacp_status)
{
-    struct bond_slave *slave;
+    struct bond_slave *slave, *primary;
    bool revalidate;

    ovs_rwlock_wrlock(&rwlock);
@@ -685,11 +734,19 @@ bond_run(struct bond *bond, enum lacp_status lacp_status)
    }

    /* Enable slaves based on link status and LACP feedback. */
+    primary = NULL;
    HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
        bond_link_status_update(slave);
        slave->change_seq = seq_read(connectivity_seq_get());
+
+        /* Discover if there is an active slave marked 'primary' */

There should be a period at the end of the comment.

Fixed.  V9 coming shortly.

+        if (bond->balance == BM_AB && slave->is_primary && slave->enabled) {
+            primary = slave;
+        }
    }
-    if (!bond->active_slave || !bond->active_slave->enabled) {
+
+    if (!bond->active_slave || !bond->active_slave->enabled ||
+        (primary && bond->active_slave != primary)) {
        bond_choose_active_slave(bond);
    }

@@ -1437,16 +1494,25 @@ bond_print_details(struct ds *ds, const struct bond *bond)
    ds_put_format(ds, "lacp_fallback_ab: %s\n",
                  bond->lacp_fallback_ab ? "true" : "false");

-    ds_put_cstr(ds, "active slave mac: ");
-    ds_put_format(ds, ETH_ADDR_FMT, ETH_ADDR_ARGS(bond->active_slave_mac));
+    bool found_primary = false;
    slave = bond_find_slave_by_mac(bond, bond->active_slave_mac);
-    ds_put_format(ds,"(%s)\n", slave ? slave->name : "none");
-
    HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
+        if (slave->is_primary) {
+            found_primary = true;
+        }
        shash_add(&slave_shash, slave->name, slave);
    }
-    sorted_slaves = shash_sort(&slave_shash);

+    ds_put_format(ds, "active-backup primary: %s%s\n",
+                  bond->primary ? bond->primary : "<none>",
+                  (!found_primary && bond->primary)
+                  ? " (no such slave)" : "");
+
+    ds_put_cstr(ds, "active slave mac: ");
+    ds_put_format(ds, ETH_ADDR_FMT, ETH_ADDR_ARGS(bond->active_slave_mac));
+    ds_put_format(ds,"(%s)\n", slave ? slave->name : "none");
+
+    sorted_slaves = shash_sort(&slave_shash);
    for (i = 0; i < shash_count(&slave_shash); i++) {
        struct bond_entry *be;

@@ -1906,6 +1972,13 @@ bond_choose_slave(const struct bond *bond)
{
    struct bond_slave *slave, *best;

+    /* If there's a primary and it's active, return that. */
+    HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
+        if (slave->is_primary && slave->enabled) {
+            return slave;
+        }
+    }
+
    /* Find the last active slave. */
    slave = bond_find_slave_by_mac(bond, bond->active_slave_mac);
    if (slave && slave->enabled) {
diff --git a/ofproto/bond.h b/ofproto/bond.h
index 40c3258dc..1a42a37c9 100644
--- a/ofproto/bond.h
+++ b/ofproto/bond.h
@@ -45,6 +45,7 @@ struct bond_settings {

    /* Balancing configuration. */
    enum bond_mode balance;
+    const char *primary;        /* For AB balance, primary interface name. */
    int rebalance_interval;     /* Milliseconds between rebalances.
                                   Zero to disable rebalancing. */

diff --git a/tests/lacp.at<http://lacp.at> b/tests/lacp.at<http://lacp.at>
index df1691731..5257f0cce 100644
--- a/tests/lacp.at<http://lacp.at>
+++ b/tests/lacp.at<http://lacp.at>
@@ -126,6 +126,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>
active slave mac: 00:00:00:00:00:00(none)

slave p1: disabled
@@ -292,6 +293,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>

slave p0: enabled
  may_enable: true
@@ -308,6 +310,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>

slave p2: enabled
  may_enable: true
@@ -431,6 +434,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>
<active slave mac del>

slave p0: disabled
@@ -449,6 +453,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>
<active slave mac del>

slave p2: disabled
@@ -565,6 +570,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>
<active slave mac del>

slave p0: disabled
@@ -583,6 +589,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>
<active slave mac del>

slave p2: disabled
@@ -704,6 +711,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>
<active slave mac del>

slave p0: enabled
@@ -722,6 +730,7 @@ updelay: 0 ms
downdelay: 0 ms
lacp_status: negotiated
lacp_fallback_ab: false
+active-backup primary: <none>
<active slave mac del>

slave p2: enabled
diff --git a/tests/ofproto-dpif.at<http://ofproto-dpif.at> b/tests/ofproto-dpif.at<http://ofproto-dpif.at>
index e3402e7b8..808200800 100644
--- a/tests/ofproto-dpif.at<http://ofproto-dpif.at>
+++ b/tests/ofproto-dpif.at<http://ofproto-dpif.at>
@@ -29,12 +29,16 @@ AT_CHECK([ovs-appctl revalidator/wait])
OVS_VSWITCHD_STOP
AT_CLEANUP

-AT_SETUP([ofproto-dpif - active-backup bonding])
-# Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and p2
-#    and br1 with interfaces p3, p4 and p8.
-# toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
+AT_SETUP([ofproto-dpif - active-backup bonding (with primary)])
+
+dnl Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and
+dnl    p2 (p1 as primary) and br1 with interfaces p3, p4 and p8.
+dnl toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
+dnl With p1 down and p2 up/active, bring p1 back up.  Since p1 is the primary,
+dnl it should become active.
OVS_VSWITCHD_START(
-  [add-bond br0 bond0 p1 p2 bond_mode=active-backup --\
+  [add-bond br0 bond0 p1 p2 bond_mode=active-backup \
+                other_config:bond-primary=p1 -- \
   set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
   set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
   add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy -- \
@@ -45,9 +49,202 @@ OVS_VSWITCHD_START(
   add-port br1 p3 -- set interface p3 type=dummy options:stream=unix:$OVS_RUNDIR/p1.sock ofport_request=3 -- \
   add-port br1 p4 -- set interface p4 type=dummy options:stream=unix:$OVS_RUNDIR/p2.sock ofport_request=4 -- \
   add-port br1 p8 -- set interface p8 ofport_request=8 type=dummy --])
+AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
WAIT_FOR_DUMMY_PORTS([p3], [p4])
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: p1'`"])
+
+
+AT_CHECK([ovs-ofctl add-flow br0 action=normal])
+AT_CHECK([ovs-ofctl add-flow br1 action=normal])
+ovs-appctl netdev-dummy/set-admin-state up
+ovs-appctl time/warp 100
+ovs-appctl netdev-dummy/set-admin-state p2 down
+ovs-appctl time/stop
+ovs-appctl time/warp 100
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(src=10.0.0.2,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(src=10.0.0.3,dst=10.0.0.4,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+ovs-appctl time/warp 100
+ovs-appctl netdev-dummy/set-admin-state p2 up
+ovs-appctl netdev-dummy/set-admin-state p1 down
+ovs-appctl time/warp 100
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(src=10.0.0.5,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(src=10.0.0.6,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+ovs-appctl time/warp 2000 100
+AT_CHECK([ovs-appctl dpctl/dump-flows | grep 'in_port([[348]])' | strip_xout], [0], [dnl
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
+])
+
+ovs-appctl netdev-dummy/set-admin-state p1 up
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: p1
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
+AT_SETUP([ofproto-dpif - active-backup bonding (primary validation)])
+dnl Make a switch with 3 ports in a bond, so that when we delete one of
+dnl the ports from the bond, there are still 2 ports left and the bond
+dnl remains functional.
+OVS_VSWITCHD_START(
+  [add-bond br0 bond0 p1 p2 p3 bond_mode=active-backup \
+                other_config:bond-primary=p1 -- \
+   set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
+   set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
+   set interface p3 type=dummy options:pstream=punix:$OVS_RUNDIR/p3.sock ofport_request=3 -- \
+   add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy --])
AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])

+dnl Make sure the initial primary interface is set
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: p1'`"])
+
+dnl Down the primary interface and verify that we switched.  Then
+dnl bring the primary back and verify that we switched back to the
+dnl primary.
+ovs-appctl netdev-dummy/set-admin-state p1 down
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | fgrep 'slave p1: disabled'`"])
+ovs-appctl netdev-dummy/set-admin-state p1 up
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: p1
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+slave p3: enabled
+  may_enable: true
+
+])
+
+dnl Now delete the primary and verify that the output shows that the
+dnl primary is no longer enslaved
+ovs-vsctl --id=@p1 get Interface p1 -- remove Port bond0 interfaces @p1
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | fgrep 'active-backup primary: p1 (no such slave)'`"])
+
+dnl Now re-add the primary and verify that the output shows that the
+dnl primary is available again.
+dnl
+dnl First, get the UUIDs of the interfaces that exist on bond0.
+dnl Strip the trailing ] so that we can add a new UUID to the end.
+uuids=`ovs-vsctl get Port bond0 interfaces | sed -e 's/]//'`
+dnl Create a new port "p1" and add its UUID to the set of interfaces
+dnl on bond0.
+ovs-vsctl \
+   --id=@p1 create Interface name=p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
+   set Port bond0 interfaces="$uuids, @p1]"
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: p1
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+slave p3: enabled
+  may_enable: true
+
+])
+
+dnl Remove the "bond-primary" config directive from the bond.
+AT_CHECK([ovs-vsctl remove Port bond0 other_config bond-primary])
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: <none>
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+slave p3: enabled
+  may_enable: true
+
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
+AT_SETUP([ofproto-dpif - active-backup bonding (without primary)])
+dnl Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and p2
+dnl    and br1 with interfaces p3, p4 and p8.
+dnl toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
+OVS_VSWITCHD_START(
+  [add-bond br0 bond0 p1 p2 bond_mode=active-backup --\
+   set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
+   set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
+   add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy -- \
+   add-br br1 -- \
+   set bridge br1 other-config:hwaddr=aa:66:aa:66:00:00 -- \
+   set bridge br1 datapath-type=dummy other-config:datapath-id=1234 \
+                  fail-mode=secure -- \
+   add-port br1 p3 -- set interface p3 type=dummy options:stream=unix:$OVS_RUNDIR/p1.sock ofport_request=3 -- \
+   add-port br1 p4 -- set interface p4 type=dummy options:stream=unix:$OVS_RUNDIR/p2.sock ofport_request=4 -- \
+   add-port br1 p8 -- set interface p8 ofport_request=8 type=dummy --])
+AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
+WAIT_FOR_DUMMY_PORTS([p3], [p4])
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: <none>'`"])
+
AT_CHECK([ovs-ofctl add-flow br0 action=normal])
AT_CHECK([ovs-ofctl add-flow br1 action=normal])
ovs-appctl netdev-dummy/set-admin-state up
@@ -63,15 +260,14 @@ ovs-appctl netdev-dummy/set-admin-state p1 down
ovs-appctl time/warp 100
AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(src=10.0.0.5,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(src=10.0.0.6,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
-ovs-appctl time/warp 200 100
-sleep 1
-AT_CHECK([grep 'in_port([[348]])' ovs-vswitchd.log | filter_flow_install | strip_xout], [0], [dnl
-recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), actions: <del>
+ovs-appctl time/warp 2000 100
+AT_CHECK([ovs-appctl dpctl/dump-flows | grep 'in_port([[348]])' | strip_xout], [0], [dnl
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
])
OVS_VSWITCHD_STOP
AT_CLEANUP
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index f312efd8e..7111fbac3 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -4563,6 +4563,11 @@ port_configure_bond(struct port *port, struct bond_settings *s)
                  port->name);
    }

+    s->primary = NULL;
+    if (s->balance == BM_AB || s->lacp_fallback_ab_cfg) {
+        s->primary = smap_get(&port->cfg->other_config, "bond-primary");
+    }
+
    miimon_interval = smap_get_int(&port->cfg->other_config,
                                   "bond-miimon-interval", 0);
    if (miimon_interval <= 0) {
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index b6acb34ca..944708ed6 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -2003,6 +2003,14 @@
        This knob does not affect other balancing modes.
      </column>

+      <column name="other_config" key="bond-primary"
+              type='{"type": "string"}'>
+        If a slave interface with this name exists in the bond and
+        is up, it will be made active.  Relevant only when <ref
+        column="other_config" key="bond-mode"/> is
+        <code>active-backup</code>.
+      </column>
+
      <group title="Link Failure Detection">
        <p>
          An important part of link bonding is detecting that links are down so


--
Jeff Squyres
jsquyres@cisco.com<mailto:jsquyres@cisco.com>
diff mbox series

Patch

diff --git a/ofproto/bond.c b/ofproto/bond.c
index 9947e7531..4e634e2ce 100644
--- a/ofproto/bond.c
+++ b/ofproto/bond.c
@@ -89,6 +89,7 @@  struct bond_slave {
     /* Link status. */
     bool enabled;               /* May be chosen for flows? */
     bool may_enable;            /* Client considers this slave bondable. */
+    bool is_primary;            /* This slave is preferred over others. */
     long long delay_expires;    /* Time after which 'enabled' may change. */
 
     /* Rebalancing info.  Used only by bond_rebalance(). */
@@ -124,6 +125,7 @@  struct bond {
     uint32_t basis;             /* Basis for flow hash function. */
     bool use_lb_output_action;  /* Use lb_output action to avoid recirculation.
                                    Applicable only for Balance TCP mode. */
+    char *primary;              /* Name of the primary slave interface. */
 
     /* SLB specific bonding info. */
     struct bond_entry *hash;     /* An array of BOND_BUCKETS elements. */
@@ -241,6 +243,7 @@  bond_create(const struct bond_settings *s, struct ofproto_dpif *ofproto)
 
     bond->active_slave_mac = eth_addr_zero;
     bond->active_slave_changed = false;
+    bond->primary = NULL;
 
     bond_reconfigure(bond, s);
     return bond;
@@ -294,6 +297,7 @@  bond_unref(struct bond *bond)
     update_recirc_rules__(bond);
 
     hmap_destroy(&bond->pr_rule_ops);
+    free(bond->primary);
     free(bond->name);
     free(bond);
 }
@@ -471,6 +475,45 @@  bond_reconfigure(struct bond *bond, const struct bond_settings *s)
         bond->bond_revalidate = false;
     }
 
+    /*
+     * If a primary interface is set on the new settings:
+     * 1. If the bond has no primary previously set, save it and
+     * revalidate.
+     * 2. If the bond has a different primary previously set, save the
+     * new one and revalidate.
+     * 3. If the bond has the same primary previously set, do nothing.
+     */
+    if (!nullable_string_is_equal(bond->primary, s->primary)) {
+        free(bond->primary);
+        bond->primary = nullable_xstrdup(s->primary);
+        revalidate = true;
+    }
+
+    if (s->primary) {
+        bool changed = false;
+        if (bond->primary) {
+            if (strcmp(bond->primary, s->primary)) {
+                free(bond->primary);
+                changed = true;
+            }
+        } else {
+            changed = true;
+        }
+
+        if (changed) {
+            bond->primary = xstrdup(s->primary);
+            revalidate = true;
+        }
+    } else if (bond->primary) {
+        /*
+         * If the new settings have no primary interface, but the
+         * bond already has a primary, remove the bond's primary.
+         */
+        free(bond->primary);
+        bond->primary = NULL;
+        revalidate = true;
+    }
+
     if (bond->balance != BM_AB) {
         if (!bond->recirc_id) {
             bond->recirc_id = recirc_alloc_id(bond->ofproto);
@@ -575,6 +618,12 @@  bond_slave_register(struct bond *bond, void *slave_,
         slave->name = xstrdup(netdev_get_name(netdev));
         bond->bond_revalidate = true;
 
+        if (bond->primary && !strcmp(bond->primary, slave->name)) {
+            slave->is_primary = true;
+        } else {
+            slave->is_primary = false;
+        }
+
         slave->enabled = false;
         bond_enable_slave(slave, netdev_get_carrier(netdev));
     }
@@ -668,7 +717,7 @@  bond_slave_set_may_enable(struct bond *bond, void *slave_, bool may_enable)
 bool
 bond_run(struct bond *bond, enum lacp_status lacp_status)
 {
-    struct bond_slave *slave;
+    struct bond_slave *slave, *primary;
     bool revalidate;
 
     ovs_rwlock_wrlock(&rwlock);
@@ -685,11 +734,19 @@  bond_run(struct bond *bond, enum lacp_status lacp_status)
     }
 
     /* Enable slaves based on link status and LACP feedback. */
+    primary = NULL;
     HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
         bond_link_status_update(slave);
         slave->change_seq = seq_read(connectivity_seq_get());
+
+        /* Discover if there is an active slave marked 'primary' */
+        if (bond->balance == BM_AB && slave->is_primary && slave->enabled) {
+            primary = slave;
+        }
     }
-    if (!bond->active_slave || !bond->active_slave->enabled) {
+
+    if (!bond->active_slave || !bond->active_slave->enabled ||
+        (primary && bond->active_slave != primary)) {
         bond_choose_active_slave(bond);
     }
 
@@ -1437,16 +1494,25 @@  bond_print_details(struct ds *ds, const struct bond *bond)
     ds_put_format(ds, "lacp_fallback_ab: %s\n",
                   bond->lacp_fallback_ab ? "true" : "false");
 
-    ds_put_cstr(ds, "active slave mac: ");
-    ds_put_format(ds, ETH_ADDR_FMT, ETH_ADDR_ARGS(bond->active_slave_mac));
+    bool found_primary = false;
     slave = bond_find_slave_by_mac(bond, bond->active_slave_mac);
-    ds_put_format(ds,"(%s)\n", slave ? slave->name : "none");
-
     HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
+        if (slave->is_primary) {
+            found_primary = true;
+        }
         shash_add(&slave_shash, slave->name, slave);
     }
-    sorted_slaves = shash_sort(&slave_shash);
 
+    ds_put_format(ds, "active-backup primary: %s%s\n",
+                  bond->primary ? bond->primary : "<none>",
+                  (!found_primary && bond->primary)
+                  ? " (no such slave)" : "");
+
+    ds_put_cstr(ds, "active slave mac: ");
+    ds_put_format(ds, ETH_ADDR_FMT, ETH_ADDR_ARGS(bond->active_slave_mac));
+    ds_put_format(ds,"(%s)\n", slave ? slave->name : "none");
+
+    sorted_slaves = shash_sort(&slave_shash);
     for (i = 0; i < shash_count(&slave_shash); i++) {
         struct bond_entry *be;
 
@@ -1906,6 +1972,13 @@  bond_choose_slave(const struct bond *bond)
 {
     struct bond_slave *slave, *best;
 
+    /* If there's a primary and it's active, return that. */
+    HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
+        if (slave->is_primary && slave->enabled) {
+            return slave;
+        }
+    }
+
     /* Find the last active slave. */
     slave = bond_find_slave_by_mac(bond, bond->active_slave_mac);
     if (slave && slave->enabled) {
diff --git a/ofproto/bond.h b/ofproto/bond.h
index 40c3258dc..1a42a37c9 100644
--- a/ofproto/bond.h
+++ b/ofproto/bond.h
@@ -45,6 +45,7 @@  struct bond_settings {
 
     /* Balancing configuration. */
     enum bond_mode balance;
+    const char *primary;        /* For AB balance, primary interface name. */
     int rebalance_interval;     /* Milliseconds between rebalances.
                                    Zero to disable rebalancing. */
 
diff --git a/tests/lacp.at b/tests/lacp.at
index df1691731..5257f0cce 100644
--- a/tests/lacp.at
+++ b/tests/lacp.at
@@ -126,6 +126,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 active slave mac: 00:00:00:00:00:00(none)
 
 slave p1: disabled
@@ -292,6 +293,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 
 slave p0: enabled
   may_enable: true
@@ -308,6 +310,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 
 slave p2: enabled
   may_enable: true
@@ -431,6 +434,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 <active slave mac del>
 
 slave p0: disabled
@@ -449,6 +453,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 <active slave mac del>
 
 slave p2: disabled
@@ -565,6 +570,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 <active slave mac del>
 
 slave p0: disabled
@@ -583,6 +589,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 <active slave mac del>
 
 slave p2: disabled
@@ -704,6 +711,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 <active slave mac del>
 
 slave p0: enabled
@@ -722,6 +730,7 @@  updelay: 0 ms
 downdelay: 0 ms
 lacp_status: negotiated
 lacp_fallback_ab: false
+active-backup primary: <none>
 <active slave mac del>
 
 slave p2: enabled
diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
index e3402e7b8..808200800 100644
--- a/tests/ofproto-dpif.at
+++ b/tests/ofproto-dpif.at
@@ -29,12 +29,16 @@  AT_CHECK([ovs-appctl revalidator/wait])
 OVS_VSWITCHD_STOP
 AT_CLEANUP
 
-AT_SETUP([ofproto-dpif - active-backup bonding])
-# Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and p2
-#    and br1 with interfaces p3, p4 and p8.
-# toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
+AT_SETUP([ofproto-dpif - active-backup bonding (with primary)])
+
+dnl Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and
+dnl    p2 (p1 as primary) and br1 with interfaces p3, p4 and p8.
+dnl toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
+dnl With p1 down and p2 up/active, bring p1 back up.  Since p1 is the primary,
+dnl it should become active.
 OVS_VSWITCHD_START(
-  [add-bond br0 bond0 p1 p2 bond_mode=active-backup --\
+  [add-bond br0 bond0 p1 p2 bond_mode=active-backup \
+                other_config:bond-primary=p1 -- \
    set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
    set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
    add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy -- \
@@ -45,9 +49,202 @@  OVS_VSWITCHD_START(
    add-port br1 p3 -- set interface p3 type=dummy options:stream=unix:$OVS_RUNDIR/p1.sock ofport_request=3 -- \
    add-port br1 p4 -- set interface p4 type=dummy options:stream=unix:$OVS_RUNDIR/p2.sock ofport_request=4 -- \
    add-port br1 p8 -- set interface p8 ofport_request=8 type=dummy --])
+AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
 WAIT_FOR_DUMMY_PORTS([p3], [p4])
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: p1'`"])
+
+
+AT_CHECK([ovs-ofctl add-flow br0 action=normal])
+AT_CHECK([ovs-ofctl add-flow br1 action=normal])
+ovs-appctl netdev-dummy/set-admin-state up
+ovs-appctl time/warp 100
+ovs-appctl netdev-dummy/set-admin-state p2 down
+ovs-appctl time/stop
+ovs-appctl time/warp 100
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(src=10.0.0.2,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(src=10.0.0.3,dst=10.0.0.4,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+ovs-appctl time/warp 100
+ovs-appctl netdev-dummy/set-admin-state p2 up
+ovs-appctl netdev-dummy/set-admin-state p1 down
+ovs-appctl time/warp 100
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(src=10.0.0.5,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(src=10.0.0.6,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
+ovs-appctl time/warp 2000 100
+AT_CHECK([ovs-appctl dpctl/dump-flows | grep 'in_port([[348]])' | strip_xout], [0], [dnl
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
+])
+
+ovs-appctl netdev-dummy/set-admin-state p1 up
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: p1
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
+AT_SETUP([ofproto-dpif - active-backup bonding (primary validation)])
+dnl Make a switch with 3 ports in a bond, so that when we delete one of
+dnl the ports from the bond, there are still 2 ports left and the bond
+dnl remains functional.
+OVS_VSWITCHD_START(
+  [add-bond br0 bond0 p1 p2 p3 bond_mode=active-backup \
+                other_config:bond-primary=p1 -- \
+   set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
+   set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
+   set interface p3 type=dummy options:pstream=punix:$OVS_RUNDIR/p3.sock ofport_request=3 -- \
+   add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy --])
 AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
 
+dnl Make sure the initial primary interface is set
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: p1'`"])
+
+dnl Down the primary interface and verify that we switched.  Then
+dnl bring the primary back and verify that we switched back to the
+dnl primary.
+ovs-appctl netdev-dummy/set-admin-state p1 down
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | fgrep 'slave p1: disabled'`"])
+ovs-appctl netdev-dummy/set-admin-state p1 up
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: p1
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+slave p3: enabled
+  may_enable: true
+
+])
+
+dnl Now delete the primary and verify that the output shows that the
+dnl primary is no longer enslaved
+ovs-vsctl --id=@p1 get Interface p1 -- remove Port bond0 interfaces @p1
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | fgrep 'active-backup primary: p1 (no such slave)'`"])
+
+dnl Now re-add the primary and verify that the output shows that the
+dnl primary is available again.
+dnl
+dnl First, get the UUIDs of the interfaces that exist on bond0.
+dnl Strip the trailing ] so that we can add a new UUID to the end.
+uuids=`ovs-vsctl get Port bond0 interfaces | sed -e 's/]//'`
+dnl Create a new port "p1" and add its UUID to the set of interfaces
+dnl on bond0.
+ovs-vsctl \
+   --id=@p1 create Interface name=p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
+   set Port bond0 interfaces="$uuids, @p1]"
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: p1
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+slave p3: enabled
+  may_enable: true
+
+])
+
+dnl Remove the "bond-primary" config directive from the bond.
+AT_CHECK([ovs-vsctl remove Port bond0 other_config bond-primary])
+ovs-appctl time/warp 100
+OVS_WAIT_UNTIL([ovs-appctl bond/show | STRIP_RECIRC_ID | STRIP_ACTIVE_SLAVE_MAC], [0], [dnl
+---- bond0 ----
+bond_mode: active-backup
+bond may use recirculation: no, <del>
+bond-hash-basis: 0
+updelay: 0 ms
+downdelay: 0 ms
+lacp_status: off
+lacp_fallback_ab: false
+active-backup primary: <none>
+<active slave mac del>
+
+slave p1: enabled
+  active slave
+  may_enable: true
+
+slave p2: enabled
+  may_enable: true
+
+slave p3: enabled
+  may_enable: true
+
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
+
+AT_SETUP([ofproto-dpif - active-backup bonding (without primary)])
+dnl Create br0 with interfaces p1, p2 and p7, creating bond0 with p1 and p2
+dnl    and br1 with interfaces p3, p4 and p8.
+dnl toggle p1,p2 of bond0 up and down to test bonding in active-backup mode.
+OVS_VSWITCHD_START(
+  [add-bond br0 bond0 p1 p2 bond_mode=active-backup --\
+   set interface p1 type=dummy options:pstream=punix:$OVS_RUNDIR/p1.sock ofport_request=1 -- \
+   set interface p2 type=dummy options:pstream=punix:$OVS_RUNDIR/p2.sock ofport_request=2 -- \
+   add-port br0 p7 -- set interface p7 ofport_request=7 type=dummy -- \
+   add-br br1 -- \
+   set bridge br1 other-config:hwaddr=aa:66:aa:66:00:00 -- \
+   set bridge br1 datapath-type=dummy other-config:datapath-id=1234 \
+                  fail-mode=secure -- \
+   add-port br1 p3 -- set interface p3 type=dummy options:stream=unix:$OVS_RUNDIR/p1.sock ofport_request=3 -- \
+   add-port br1 p4 -- set interface p4 type=dummy options:stream=unix:$OVS_RUNDIR/p2.sock ofport_request=4 -- \
+   add-port br1 p8 -- set interface p8 ofport_request=8 type=dummy --])
+AT_CHECK([ovs-appctl vlog/set dpif:dbg dpif_netdev:dbg])
+WAIT_FOR_DUMMY_PORTS([p3], [p4])
+OVS_WAIT_UNTIL([test -n "`ovs-appctl bond/show | grep 'active-backup primary: <none>'`"])
+
 AT_CHECK([ovs-ofctl add-flow br0 action=normal])
 AT_CHECK([ovs-ofctl add-flow br1 action=normal])
 ovs-appctl netdev-dummy/set-admin-state up
@@ -63,15 +260,14 @@  ovs-appctl netdev-dummy/set-admin-state p1 down
 ovs-appctl time/warp 100
 AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(src=10.0.0.5,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
 AT_CHECK([ovs-appctl netdev-dummy/receive p7 'in_port(7),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(src=10.0.0.6,dst=10.0.0.1,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
-ovs-appctl time/warp 200 100
-sleep 1
-AT_CHECK([grep 'in_port([[348]])' ovs-vswitchd.log | filter_flow_install | strip_xout], [0], [dnl
-recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), actions: <del>
-recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), actions: <del>
+ovs-appctl time/warp 2000 100
+AT_CHECK([ovs-appctl dpctl/dump-flows | grep 'in_port([[348]])' | strip_xout], [0], [dnl
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(3),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=50:54:00:00:00:0c),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0d),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0e),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
+recirc_id(0),in_port(4),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:0b,dst=ff:ff:ff:ff:ff:ff),eth_type(0x8035), packets:0, bytes:0, used:never, actions: <del>
 ])
 OVS_VSWITCHD_STOP
 AT_CLEANUP
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index f312efd8e..7111fbac3 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -4563,6 +4563,11 @@  port_configure_bond(struct port *port, struct bond_settings *s)
                   port->name);
     }
 
+    s->primary = NULL;
+    if (s->balance == BM_AB || s->lacp_fallback_ab_cfg) {
+        s->primary = smap_get(&port->cfg->other_config, "bond-primary");
+    }
+
     miimon_interval = smap_get_int(&port->cfg->other_config,
                                    "bond-miimon-interval", 0);
     if (miimon_interval <= 0) {
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index b6acb34ca..944708ed6 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -2003,6 +2003,14 @@ 
         This knob does not affect other balancing modes.
       </column>
 
+      <column name="other_config" key="bond-primary"
+              type='{"type": "string"}'>
+        If a slave interface with this name exists in the bond and
+        is up, it will be made active.  Relevant only when <ref
+        column="other_config" key="bond-mode"/> is
+        <code>active-backup</code>.
+      </column>
+
       <group title="Link Failure Detection">
         <p>
           An important part of link bonding is detecting that links are down so