Configurator

Configurator is a sync service that keeps Kubernetes deployments in sync with the ConfigMap updates.

When used with kustomize,
- Resource postfix as way to version control ConfigMaps
- Automatically triggers a rolling update on deployments referring to a configMap version
- Periodically purges unused ConfigMap versions

Supported Versions

• K8s 1.16

Dependencies

Install kustomize in the Kuberentes client environment from where configMap creation needs to be triggered.
- kustomize

Building Configurator

Build the source code

dep ensure
go build main.go

How to use ?

Once configurator is compiled, start the service.

./main ~/.kube/config
curl -X POST -d '{"labels":[{"nameSpace":"default","configMap":"my-java"}]}' http://localhost:8050/api/watcher

Use kustomize to create or update configMaps. Say kustmization.yaml file must look like this. Note that the labels under option section must contain name=<configmapname></configmapname>

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
# These labels are added to all configmaps and secrets.
configMapGenerator:
- name: my-java
  behavior: create
  literals:
  - JAVA_TOOL_OPTIONS=-agentlib:hprof
  - JAVA_TEST=javatest
  - JAVA_HOME=/home/vino/addo
  options:
    disableNameSuffixHash: false
    labels:
      name: my-java

Build the configMap using the kustomization.yaml file.

kustomize build . | kubectl apply -f -

Create deployment with the newly created configMap along with the postfix. Please note the metadata label must contain the config name and the config postfix that was created initially. say <configname>=<postfix>. Under the VolumeMounts section use the complete name of the configMap along with the postfix.</postfix></configname>

apiVersion: apps/v1
kind: Deployment
metadata:
  name: busybox-deployment
  labels:
    my-java: d6f8m44fmg
    app: busybox
spec:
  replicas: 1
  revisionHistoryLimit: 1
  strategy: 
    type: RollingUpdate
  selector:
    matchLabels:
      app: busybox
  template:
    metadata:
      labels:
        app: busybox
    spec:
      containers:
      - name: busybox
        image: busybox
        imagePullPolicy: IfNotPresent
        command: ['sh', '-c', 'echo Container 1 is Running ; sleep 3600']
        volumeMounts:
        - mountPath: /test
          name: test-config
      volumes:
      - name: test-config
        configMap:
          name: my-java-d6f8m44fmg

Whenever a new configMap is created through kustomize, Configurator will automatically sync up the related deployments automatically.

Todos

• Sync Secretes with Deployments
• Handle Stateful Sets
• Move Configurator to Operator Framework

License

Apache License 2.0