Running a shell script to initialize pods in kubernetes (initializing my db cluster)

I finally decided to take the approach of creating a config file with the script we want to run and then call this configmap from inside the volume.

this is a short explanation:

In my pod.yaml file there is a VolumeMount called "/pgcong" which is the directory that the docker image reads any SQL script that you put there and run it when the pod is starting. And inside Volumes I will put the configmap name (postgres-init-script-configmap) which is the name of the config defined inside the configmap.yaml file.

There is no need to create the configmap using kubernetes, The pod will take the configuration from the configmap file as long as you place it in the same directory as the pod.yaml .

my POD yaml file:

apiVersion: v1
kind: Pod
metadata:
  name: "{{.Values.container.name.primary}}"
  labels:
    name: "{{.Values.container.name.primary}}"
spec:
  securityContext:
    fsGroup: 26
  restartPolicy: {{default "Always" .Values.restartPolicy}}

  containers:
  - name: {{.Values.container.name.primary}}
    image: "{{.Values.image.repository}}/{{.Values.image.container}}:{{.Values.image.tag}}"
    ports:
    - containerPort: {{.Values.container.port}}
    env:
    - name: PGHOST
      value: /tmp
    - name: PG_PRIMARY_USER
      value: primaryuser
    - name: PG_MODE
      value: primary
    resources:
      requests:
        cpu: {{ .Values.resources.cpu }}
        memory: {{ .Values.resources.memory }}
    volumeMounts:
    - mountPath: /pgconf
      name: init-script
      readOnly: true
  volumes:
  - name: init-script
    configMap:
      name: postgres-init-script-configmap

my configmap.yaml (Which contains the SQL script that will initial the DB):

apiVersion: v1
kind: ConfigMap
metadata:
  name: postgres-init-script-configmap
data:
  setup.sql: |-
    CREATE USER david WITH PASSWORD 'david';