Support multiple operator replicas with leader election

eclipse-theia/theia-cloud#201

* allow to specify number of operator replicas
* allow operator to work with leases

charts/theia.cloud-base/Chart.yaml

@@ -15,7 +15,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.8.1-v001-MS1
+version: 0.8.1-v002
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to

charts/theia.cloud-base/templates/operator-role.yaml

@@ -12,6 +12,7 @@ rules:
       - theia.cloud
       - networking.k8s.io
       - apps
+      - coordination.k8s.io
     resources:
       - customresourcedefinitions
       - appdefinitions
@@ -23,6 +24,7 @@ rules:
       - services
       - configmaps
       - deployments
-    verbs: ["list", "create", "watch", "get", "patch", "delete"]
+      - leases
+    verbs: ["list", "create", "watch", "get", "patch", "delete", "update"]
 
 {{- end }}

charts/theia.cloud/Chart.yaml

@@ -15,7 +15,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.8.1-v002-MS1
+version: 0.8.1-v003
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to

charts/theia.cloud/templates/operator.yaml

@@ -6,7 +6,7 @@ metadata:
     app: operator
   namespace: {{ .Release.Namespace }}
 spec:
-  replicas: 1
+  replicas: {{ tpl (.Values.operator.replicas | toString) . }}
   selector:
     matchLabels:
       app: operator
@@ -71,6 +71,12 @@ spec:
           - "{{ tpl (.Values.monitor.activityTracker.interval | toString) . }}"
           {{- end }}
           {{- end }}
+          - "--leaderLeaseDuration"
+          - "{{ tpl (.Values.operator.leaderElection.leaseDuration | toString) . }}"
+          - "--leaderRenewDeadline"
+          - "{{ tpl (.Values.operator.leaderElection.renewDeadline | toString) . }}"
+          - "--leaderRetryPeriod"
+          - "{{ tpl (.Values.operator.leaderElection.retryPeriod | toString) . }}"
       {{- if .Values.operator.imagePullSecret }}
       imagePullSecrets:
         - name: {{ tpl (.Values.operator.imagePullSecret | toString) . }}

charts/theia.cloud/values.yaml

@@ -184,6 +184,15 @@ operator:
   # See https://kubernetes.io/docs/reference/kubernetes-api/common-definitions/quantity/
   requestedStorage: "250Mi"
 
+  # Number of operator instances to create
+  replicas: 2
+
+  # Options to influence the operator's leader election
+  leaderElection:
+    leaseDuration: 6
+    renewDeadline: 4
+    retryPeriod: 1
+
 # Values of the Theia.cloud REST service
 service:
   # The image to use