Telegraf helm charts PodDisruptionBudgets don't make sense

[cvalaas]

By default, the telegraf deployments have 1 replica and a PDB of MinAvailable: 1, this makes the pods unevictable and scaling down kubernetes nodes not possible. I would suggest changing pdb: create: to false as the default in helm-charts/charts/telegraf/values.yaml

See here:

If you set maxUnavailable to 0% or 0, or you set minAvailable to 100% or the number of replicas, you are requiring zero voluntary evictions. When you set zero voluntary evictions for a workload object such as ReplicaSet, then you cannot successfully drain a Node running one of those Pods. If you try to drain a Node where an unevictable Pod is running, the drain never completes. This is permitted as per the semantics of PodDisruptionBudget.

https://kubernetes.io/docs/tasks/run-application/configure-pdb/

[broomfn]

+1 This has just caused me issues upgrading my Kubernetes node pool version, it's preventing upgrades. Obviously this is a serious security issue if the nodes cannot be upgraded.

As a work around I've had to manually delete the PDB which also isn't great for uptime reliability

[dmity-st]

+1 sounds reasonable