Manual fix for missing priorityClass after helm upgrade

fix-helm-k8s-missing-priorityClass.md

Problem Statement

I've been hitting cases where kubernetes cluster actions are blocked due to priorityClass being absent after a helm install --upgrade.

For example:

  Type     Reason        Age                  From                    Message
  ----     ------        ----                 ----                    -------
  Warning  FailedCreate  3m (x1405 over 11h)  statefulset-controller  create Pod elasticsearch-data-2 in StatefulSet elasticsearch-data failed error: pods "elasticsearch-data-2" is forbidden: no PriorityClass with name elasticsearch-data was found```

```bash
$ helm version
Client: &version.Version{SemVer:"v2.13.1", GitCommit:"618447cbf203d147601b4b9bd7f8c37a5d39fbb4", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.13.1", GitCommit:"618447cbf203d147601b4b9bd7f8c37a5d39fbb4", GitTreeState:"clean"}```

```bash
$ kubectl version
Client Version: version.Info{Major:"1", Minor:"12+", GitVersion:"v1.12.7-3+1a4d39a9763d23", GitCommit:"1a4d39a9763d23548d16e262d6dbe0fb2198a8ce", GitTreeState:"clean", BuildDate:"2019-03-27T01:47:38Z", GoVersion:"go1.10.8", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"12+", GitVersion:"v1.12.7-3+1a4d39a9763d23", GitCommit:"1a4d39a9763d23548d16e262d6dbe0fb2198a8ce", GitTreeState:"clean", BuildDate:"2019-03-27T01:47:38Z", GoVersion:"go1.10.8", Compiler:"gc", Platform:"linux/amd64"}

Manual Solution

Manually create the missing PriorityClass.

echo 'apiVersion: scheduling.k8s.io/v1beta1
kind: PriorityClass
metadata:
  name: elasticsearch-data
value: 1000000
globalDefault: false
description: "Critical for elasticsearch-data workloads"' | kubectl apply -f -