Add note for LB behaviour for cordoned nodes. (#18784)

* Add note for LB behaviour for cordoned nodes. See also https://github.com/kubernetes/kubernetes/issues/65013 This is a reasonably common pitfall: `kubectl cordon <all nodes>` will also drop all LB traffic to the cluster, but this is not documented anywhere but in issues, when found it is usually already too late. * Update with feedback
2020-02-05 23:31:56 +01:00
parent 0179d4afaf
commit 37ec720fa8
1 changed files with 6 additions and 0 deletions
@@ -275,6 +275,12 @@ and do not respect the unschedulable attribute on a node. This assumes that daem
 the machine even if it is being drained of applications while it prepares for a reboot.
 {{< /note >}}

+{{< caution >}}
+`kubectl cordon` marks a node as 'unschedulable', which has the side effect of the service
+controller removing the node from any LoadBalancer node target lists it was previously 
+eligible for, effectively removing incoming load balancer traffic from the cordoned node(s).
+{{< /caution >}}
+
 ### Node capacity

 The capacity of the node (number of cpus and amount of memory) is part of the node object.