[ovs-dev] [PATCH] bond: Warn of imminent default bond_mode change.

[Ethan Jackson]

Post version 1.4.*, we are planning to change the default bond_mode
from balance-slb to active-backup.  This commit warns users of the
change so that they can prepare.
---
 NEWS              |    7 +++++++
 vswitchd/bridge.c |   20 +++++++++++++++-----
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/NEWS b/NEWS
index 61b74dd..e0cbfc8 100644
--- a/NEWS
+++ b/NEWS
@@ -29,6 +29,13 @@ v1.4.0 - xx xxx xxxx
         and connectivity issues. This tool currently is not included in RH or
         Xen packages.
     - RHEL packaging now supports integration with Red Hat network scripts.
+    - bonding:
+      - Post 1.4.*, OVS will be changing the default bond mode from balance-slb
+        to active-backup.  SLB bonds carry significant risks with them
+        (documented vswitchd/INTERNALS) which we want to prevent unsuspecting
+        users from running into.  Users are advised to update any scripts or
+        configuration which may be negatively impacted by explicitly setting
+        the bond mode which they want to use.
 
 
 v1.3.0 - xx xxx xxxx
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index de773f6..e89855e 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -2740,11 +2740,21 @@ port_configure_bond(struct port *port, struct bond_settings *s,
 
     s->name = port->name;
     s->balance = BM_SLB;
-    if (port->cfg->bond_mode
-        && !bond_mode_from_string(&s->balance, port->cfg->bond_mode)) {
-        VLOG_WARN("port %s: unknown bond_mode %s, defaulting to %s",
-                  port->name, port->cfg->bond_mode,
-                  bond_mode_to_string(s->balance));
+    if (port->cfg->bond_mode) {
+        if (!bond_mode_from_string(&s->balance, port->cfg->bond_mode)) {
+            VLOG_WARN("port %s: unknown bond_mode %s, defaulting to %s",
+                      port->name, port->cfg->bond_mode,
+                      bond_mode_to_string(s->balance));
+        }
+    } else {
+        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
+
+        /* XXX: Post version 1.4.*, change the default bond_mode to
+         * active-backup.  Until then, warn that the change is imminent. */
+        VLOG_WARN_RL(&rl, "port %s: Using the default bond_mode %s. Note that"
+                     " in future versions, the default bond_mode is expected"
+                     " to change to active-backup", port->name,
+                     bond_mode_to_string(s->balance));
     }
     if (s->balance == BM_SLB && port->bridge->cfg->n_flood_vlans) {
         VLOG_WARN("port %s: SLB bonds are incompatible with flood_vlans, "
-- 
1.7.7.1