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🐛 Fix drain log for unreachable Nodes #11147

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Merged
merged 1 commit into from
Sep 9, 2024
Merged

🐛 Fix drain log for unreachable Nodes #11147

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10 changes: 9 additions & 1 deletion internal/controllers/machine/machine_controller.go
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Original file line number Diff line number Diff line change
Expand Up @@ -686,7 +686,15 @@ func (r *Reconciler) drainNode(ctx context.Context, cluster *clusterv1.Cluster,
// Override the grace period of pods to reduce the time needed to skip them.
drainer.GracePeriodSeconds = 1

log.V(3).Info("Node is unreachable, draining will use 1s GracePeriodSeconds and will ignore all Pods that have a deletionTimestamp > 1s old. PDBs are still honored.")
// Our drain code still respects PDBs when evicting Pods, but that does not mean they are respected
// in general by the entire system.
// When a Node becomes unreachable the following happens:
// * node.kubernetes.io/unreachable:NoExecute taint is set on the Node
// * taint manager will evict Pods immediately because of the NoExecute taint (without respecting PDBs)
// * https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/#concepts
// "NoExecute": "Pods that do not tolerate the taint are evicted immediately""
// * our drain code will now ignore the Pods (as they quickly have a deletionTimestamp older than 2 seconds)
log.V(3).Info("Node is unreachable, draining will use 1s GracePeriodSeconds and will ignore all Pods that have a deletionTimestamp > 1s old")
}

if err := drainer.CordonNode(ctx, node); err != nil {
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