Enable leader election for Cozystack (#23)

packages/core/installer/images/installer/Dockerfile

@@ -1,3 +1,15 @@
+FROM golang:alpine3.19 as k8s-await-election-builder
+
+ARG K8S_AWAIT_ELECTION_GITREPO=https://github.com/LINBIT/k8s-await-election
+ARG K8S_AWAIT_ELECTION_VERSION=0.4.1
+
+RUN apk add --no-cache git make
+RUN git clone ${K8S_AWAIT_ELECTION_GITREPO} /usr/local/go/k8s-await-election/ \
+ && cd /usr/local/go/k8s-await-election \
+ && git reset --hard v${K8S_AWAIT_ELECTION_VERSION} \
+ && make \
+ && mv ./out/k8s-await-election-amd64 /k8s-await-election
+
 FROM alpine:3.19 AS builder
 
 RUN apk add --no-cache make git
@@ -18,7 +30,8 @@ COPY scripts /cozystack/scripts
 COPY --from=builder /src/packages/core /cozystack/packages/core
 COPY --from=builder /src/packages/system /cozystack/packages/system
 COPY --from=builder /src/_out/repos /cozystack/assets/repos
+COPY --from=k8s-await-election-builder /k8s-await-election /usr/bin/k8s-await-election
 COPY dashboards /cozystack/assets/dashboards
 
 WORKDIR /cozystack
-ENTRYPOINT [ "/cozystack/scripts/installer.sh" ]
+ENTRYPOINT ["/usr/bin/k8s-await-election", "/cozystack/scripts/installer.sh" ]

packages/core/installer/templates/cozystack.yaml

@@ -41,8 +41,6 @@ spec:
   selector:
     matchLabels:
       app: cozystack
-  strategy:
-    type: Recreate
   template:
     metadata:
       labels:
@@ -58,6 +56,18 @@ spec:
           value: localhost
         - name: KUBERNETES_SERVICE_PORT
           value: "7445"
+        - name: K8S_AWAIT_ELECTION_ENABLED
+          value: "1"
+        - name: K8S_AWAIT_ELECTION_NAME
+          value: cozystack
+        - name: K8S_AWAIT_ELECTION_LOCK_NAME
+          value: cozystack
+        - name: K8S_AWAIT_ELECTION_LOCK_NAMESPACE
+          value: cozy-system
+        - name: K8S_AWAIT_ELECTION_IDENTITY
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.name
       - name: darkhttpd
         image: "{{ .Files.Get "images/installer.tag" | trim }}@{{ index (.Files.Get "images/installer.json" | fromJson) "containerimage.digest" }}"
         command: