how to link and run mysql database and tomcat server on kubernetes clusture?

问题

How to link my tomcat container having war file in webapps folder to another container having mysql database.currently if i start my war file in tomcat manager app i get error saying could not start application at contextpath /data-core-0.0.1-SNAPSHOT catalina lifecycle exception.

I think my tomcat container cant access the mysql database container!!

statefulset.yaml

serviceName: mysql
 template:
  metadata:
   labels:
    name: mysql
  spec:
   containers:
    - name: mysql
      image: suji165475/vignesh:latest
      ports:
       - containerPort: 3306
      volumeMounts:
       - name: mysql-initdb
         mountPath: /docker-entrypoint-initdb.d
   volumes:
    - name: mysql-initdb
      persistentVolumeClaim:
       claimName: mysql-initdb-pv-claim

persistantvolumeclaim.yaml

kind: PersistentVolume
apiVersion: v1
metadata:
  name: mysql-initdb-pv-volume
  labels:
    type: local
    app: mysql
spec:
  storageClassName: manual
  capacity:
    storage: 1Mi
  accessModes:
    - ReadOnlyMany
  hostPath:
    path: "/tmp/data"

---

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: mysql-initdb-pv-claim
  labels:
    app: mysql
spec:
  storageClassName: manual
  accessModes:
    - ReadOnlyMany
  resources:
    requests:
      storage: 1Mi

tomcatdeployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat-deployment
  labels:
    app: tomcat
spec:
  replicas: 1
  selector:
    matchLabels:
      app: tomcat
  template:
    metadata:
      labels:
        app: tomcat
    spec:
      containers:
      - name: tomcat
        image: suji165475/vignesh:tomcatserver
        ports:
        - containerPort: 8080

回答1:

You have to crate service for mysql and consume that service name in tomcat service so tomcat pod will be able to talk with mysql server.

apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  ports:
  - port: 3306
  selector:
    app: mysql
  clusterIP: None
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - image: mysql:5.6
        name: mysql
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: <value>
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pv-claim

Now deployment for tomcat :

apiVersion: v1
kind: Service
metadata:
  name: tomcat
  labels:
    app: tomcat
spec:
  ports:
  - name: http
    port: 80
    targetPort: 80
  - name: https
    port: 443
    targetPort: 443
  selector:
    app: tomcat
    tier: frontend
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat
  labels:
    app: tomcat
spec:
  selector:
    matchLabels:
      app: tomcat
      tier: frontend
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: tomcat
        tier: frontend
    spec:
      containers:
      - image: <image location>
        name: tomcat
        env:
        - name: DB_PORT_3306_TCP_ADDR
          value: mysql                  #service name of mysql
        - name: DB_ENV_MYSQL_PASSWORD
          value: <Mysql password>
        - name: DB_ENV_MYSQL_USER
          value: <mysql user>
        - name: DB_ENV_MYSQL_DATABASE
          value: <database name>
        - name: DB_ENV_MYSQL_PASSWORD
          value: <Mysql password>
        ports:
        - containerPort: 80
          name: http
        - containerPort: 443
          name: https
        volumeMounts:
        - name: tomcat-persistent-storage
          mountPath: /var/data
      volumes:
      - name: tomcat-persistent-storage
        persistentVolumeClaim:
          claimName: tomcat-pv-claim

来源：https://stackoverflow.com/questions/56032430/how-to-link-and-run-mysql-database-and-tomcat-server-on-kubernetes-clusture