如何在kubernetes上运行docker-compose.yaml？

Question

My docker-compose file consisting of tomcat7 server and mysql database

version: '3'
services:
      mysql:
        image: suji165475/vignesh:latest
        ports:
          - "3066:3066"

      tomcat:
        image: suji165475/vignesh:tomcatserver
        container_name: tomcat7hope
        ports:
          - "8080:8080"

I built the images using docker files

FROM mysql
ENV MYSQL_ROOT_PASSWORD=root
ADD init.sql /docker-entrypoint-initdb.d

FROM picoded/tomcat7
COPY data-core-0.0.1-SNAPSHOT.war /usr/local/tomcat/webapps/data-core-0.0.1-SNAPSHOT.war

how to run this on kubernetes clusture?? I already tried kompose convert and my war file wont start in tomcats application manager.But the war file starts succesfully using docker-compose up.

Why am I facing this issue only in kubernetes and not when directly running docker-compose up.Please help me by letting me know what changes I should make to the kubernetes yaml files.

mysql-deployment.yaml

 apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  annotations:
    kompose.cmd: kompose convert
    kompose.version: 1.18.0 (06a2e56)
  creationTimestamp: null
  labels:
    io.kompose.service: mysql
  name: mysql
spec:
  replicas: 1
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        io.kompose.service: mysql
    spec:
      containers:
      - image: suji165475/vignesh:latest
        name: mysql
        ports:
        - containerPort: 3066
        resources: {}
      restartPolicy: Always
status: {}

tomcat-deployment.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  annotations:
    kompose.cmd: kompose convert
    kompose.version: 1.18.0 (06a2e56)
  creationTimestamp: null
  labels:
    io.kompose.service: tomcat
  name: tomcat
spec:
  replicas: 1
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        io.kompose.service: tomcat
    spec:
      containers:
      - image: suji165475/vignesh:tomcatserver
        name: tomcat7hope
        ports:
        - containerPort: 8080
        resources: {}
      restartPolicy: Always
status: {}

mysql-service.yaml

apiVersion: v1
kind: Service
metadata:
  annotations:
    kompose.cmd: kompose convert
    kompose.version: 1.18.0 (06a2e56)
  creationTimestamp: null
  labels:
    io.kompose.service: mysql
  name: mysql
spec:
  ports:
  - name: "3066"
    port: 3066
    targetPort: 3066
  selector:
    io.kompose.service: mysql
status:
  loadBalancer: {}

tomcat-service.yaml

apiVersion: v1
kind: Service
metadata:
  annotations:
    kompose.cmd: kompose convert
    kompose.version: 1.18.0 (06a2e56)
  creationTimestamp: null
  labels:
    io.kompose.service: tomcat
  name: tomcat
spec:
  ports:
  - name: "8080"
    port: 8080
    targetPort: 8080
  selector:
    io.kompose.service: tomcat
status:
  loadBalancer: {}

Answer 1

Let me make it clear, you can't "run docker-compose" on Kubernetes. If you wanted to do that, you should not be using Kubernetes.

With that said, using kompose is not such a great idea. Docker compose yaml files are all different and kompose simply makes a guess as to what the associated Kubernetes manifests would look like. If your application is very simple and you are lucky, kompose might give you your manifests ready to be deployed, but that is not usually the case.

There could be a few reasons why this is not working for you:

• your tomcat application is not correctly referencing your mysql service
• your mysql deployment is missing some variables or mounted volumes/files

Your tomcat app can refer to your mysql db through mysql:3066 and you might need to add some environment variables in your tomcat deployment such as db name, db username and db password for authentication. Here are your edited tomcat manifests:

deployment.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: tomcat
  namespace: default
  labels:
    app: tomcat
spec:
  replicas: 1
  selector:
    matchLabels:
      app: tomcat
  template:
    metadata:
      labels:
        app: tomcat
    spec:
      containers:
      - image: suji165475/vignesh:tomcatserver
        name: tomcat7hope
        ports:
        - containerPort: 8080

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: tomcat
  namespace: default
  labels:
    app: tomcat
spec:
  ports:
  - name: "8080"
    port: 8080
    targetPort: 8080
  selector:
    app: tomcat

Your mysql deployment might require a PersistentVolumeClaim or emptyDir in order to keep your data. Take a look at attached volumes and confirm that you are not missing any volume mounts or environment variables that are needed. Here are your edited mysql manifests:

deployment.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: mysql
  namespace: default
  labels:
    app: mysql
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - image: suji165475/vignesh:latest
        name: mysql
        ports:
        - containerPort: 3066
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: root

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: mysql
  namespace: default
  labels:
    app: mysql
spec:
  ports:
  - name: "3066"
    port: 3066
    targetPort: 3066
  selector:
    app: mysql