From 8243251d9eae8459f3e418b42889947ca4731bed Mon Sep 17 00:00:00 2001 From: MMeent Date: Wed, 5 Feb 2020 23:31:56 +0100 Subject: [PATCH] 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 ` 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 --- content/en/docs/concepts/architecture/nodes.md | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/content/en/docs/concepts/architecture/nodes.md b/content/en/docs/concepts/architecture/nodes.md index 2288fdc1c48f5..cb5b78d55ec63 100644 --- a/content/en/docs/concepts/architecture/nodes.md +++ b/content/en/docs/concepts/architecture/nodes.md @@ -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.