Added nodeSelector for celery deployment and migrate job (#1085)

# What this PR does
Adds nodeSelector for celery deployment and migrate job

## Which issue(s) this PR fixes
Fixes errors while deploying resources in a cluster with Gatekeeper
policy ( that restricts deployments without nodeSelector).

## Checklist

- [x] Tests updated
- [x] Documentation added
- [x] `CHANGELOG.md` updated

---------

Co-authored-by: Joey Orlando <joseph.t.orlando@gmail.com>
Co-authored-by: Joey Orlando <joey.orlando@grafana.com>

helm/oncall/templates/celery/_deployment.tpl

@@ -34,6 +34,10 @@ spec:
         {{- if eq .Values.database.type "postgresql" }}
         {{- include "oncall.postgresql.wait-for-db" . | indent 8 }}
         {{- end }}
+      {{- with .Values.celery.nodeSelector }}
+      nodeSelector:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
       containers:
         - name: {{ .Chart.Name }}
           securityContext:

helm/oncall/templates/engine/job-migrate.yaml

@@ -35,6 +35,10 @@ spec:
       serviceAccountName: {{ include "oncall.serviceAccountName" . }}
       securityContext:
         {{- toYaml .Values.podSecurityContext | nindent 8 }}
+      {{- with .Values.migrate.nodeSelector }}
+      nodeSelector:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
       containers:
       - name: {{ .Chart.Name }}-migrate
         securityContext:

helm/oncall/values.yaml

@@ -67,6 +67,9 @@ celery:
     initialDelaySeconds: 30
     periodSeconds: 300
     timeoutSeconds: 10
+  ## Node labels for pod assignment
+  ## ref: https://kubernetes.io/docs/user-guide/node-selection/
+  nodeSelector: {}
   resources: {}
     # limits:
     #   cpu: 100m
@@ -161,6 +164,9 @@ oncall:
 # Whether to run django database migrations automatically
 migrate:
   enabled: true
+  ## Node labels for pod assignment
+  ## ref: https://kubernetes.io/docs/user-guide/node-selection/
+  nodeSelector: {}
   # TTL can be unset by setting ttlSecondsAfterFinished: ""
   ttlSecondsAfterFinished: 20
   # use a helm hook to manage the migration job