How to initialize mysql container when created on Kubernetes?

According to the MySQL Docker image README, the part that is relevant to data initialization on container start-up is to ensure all your initialization files are mount to the container's /docker-entrypoint-initdb.d folder.

You can define your initial data in a ConfigMap, and mount the corresponding volume in your pod like this:

apiVersion: v1kind: Podmetadata:  name: mysqlspec:  containers:  - name: mysql    image: mysql            ports:      - containerPort: 3306    volumeMounts:      - name: mysql-initdb        mountPath: /docker-entrypoint-initdb.d  volumes:    - name: mysql-initdb      configMap:        name: mysql-initdb-config---apiVersion: v1kind: ConfigMapmetadata:  name: mysql-initdb-configdata:  initdb.sql: |    CREATE TABLE friends (id INT, name VARCHAR(256), age INT, gender VARCHAR(3));    INSERT INTO friends VALUES (1, 'John Smith', 32, 'm');    INSERT INTO friends VALUES (2, 'Lilian Worksmith', 29, 'f');    INSERT INTO friends VALUES (3, 'Michael Rupert', 27, 'm');

First: create persistent volume that contains your SQL scripts

kind: PersistentVolumeapiVersion: v1metadata:  name: mysql-initdb-pv-volume  labels:    type: local    app: mysqlspec:  storageClassName: manual  capacity:    storage: 1Mi  accessModes:    - ReadOnlyMany  hostPath:    path: "/path/to/initdb/sql/scripts"---kind: PersistentVolumeClaimapiVersion: v1metadata:  name: mysql-initdb-pv-claim  labels:    app: mysqlspec:  storageClassName: manual  accessModes:    - ReadOnlyMany  resources:    requests:      storage: 1Mi

Note: assume that you have your SQL scripts in /path/to/initdb/sql/scripts

Second: mount the volume to /docker-entrypoint-initdb.d

apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: mysqlspec:  replicas: 1  template:    metadata:      labels:        app: mysql    spec:      containers:        - name: mysql          image: mysql          imagePullPolicy: "IfNotPresent"          ports:            - containerPort: 3306          volumeMounts:            - mountPath: /docker-entrypoint-initdb.d              name: mysql-initdb      volumes:        - name: mysql-initdb          persistentVolumeClaim:            claimName: mysql-initdb-pv-claim

That's it.

Note: this applies to PostgreSQL too.

you need to create pv and pvclaim like this then deploy the mysql database

kind: PersistentVolumeapiVersion: v1metadata:  name: sfg-dev-mysql-pv-volume  labels:    type: localspec:  storageClassName: manual  capacity:    storage: 1Gi  accessModes:    - ReadWriteOnce  hostPath:    path: "/tmp/data"---kind: PersistentVolumeClaimapiVersion: v1metadata:  name: sfg-dev-mysql-pv-claimspec:  storageClassName: manual  accessModes:    - ReadWriteOnce  resources:    requests:      storage: 1Gi

create secret:

kubectl create secret generic mysql-secret --from-literal=mysql-root-password=kube1234 --from-literal=mysql-user=testadm --from-literal=mysql-password=kube1234kubectl create configmap db --from-literal=mysql-database: database

mysql deployment:

apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: sfg-dev-mysql-db  labels:    app: sfg-dev-mysqlspec:  strategy:    type: Recreate  template:    metadata:      labels:        app: sfg-dev-mysql        tier: db    spec:      containers:      - image: mysql:8.0.2        name: mysql        env:        - name: MYSQL_DATABASE          valueFrom:            configMapKeyRef:              name: db              key: mysql-database                - name: MYSQL_ROOT_PASSWORD          valueFrom:            secretKeyRef:              name: mysql-secret              key: mysql-root-password        - name: MYSQL_USER          valueFrom:            secretKeyRef:              name: mysql-secret              key: mysql-user        - name: MYSQL_PASSWORD          valueFrom:            secretKeyRef:              name: mysql-secret              key: mysql-password        ports:        - containerPort: 3306          name: mysql        volumeMounts:        - name: mysql-persistent-storage          mountPath: /var/lib/mysql      volumes:      - name: mysql-persistent-storage        persistentVolumeClaim:          claimName: sfg-dev-mysql-pv-claim