How to run spring boot mysql application docker image on kubernetes? - spring-boot

Question

My DockerFile looks like :
FROM openjdk:8-jdk-alpine
ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]
and my yml file looks like :
apiVersion: apps/v1
kind: Deployment
metadata:
name: imagename
namespace: default
spec:
replicas: 3
selector:
matchLabels:
bb: web
template:
metadata:
labels:
bb: web
spec:
containers:
- name: imagename
image: imagename:1.1
imagePullPolicy: Never
env:
- name: MYSQL_USER
value: root
ports:
- containerPort: 3306
---
apiVersion: v1
kind: Service
metadata:
name: imagename
namespace: default
spec:
type: NodePort
selector:
bb: web
ports:
- port: 8080
targetPort: 8080
nodePort: 30001
i have build docker image using below command :
docker build -t dockerimage:1.1 .
and running the docker image like :
docker run -p 8080:8080 --network=host dockerimage:1.1
When i deploy this image in kubernetes environment i am getting error :
ERROR com.zaxxer.hikari.pool.HikariPool - HikariPool-1 - Exception during pool initialization.
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
Also i have done port forwarding :
Forwarding from 127.0.0.1:13306 -> 3306
Any suggestion what is wrong with the above configuration ?

Answer 1

you need to add a service type clusterIP to your database like that:
MySQL Service:
apiVersion: v1
kind: Service
metadata:
name: mysql-service
labels:
app: mysql
spec:
ports:
- port: 3306
selector:
app: mysql
tier: mysql
clusterIP: None
MySQL PVC:
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mysql-pv-claim
labels:
app: my-db-pv-claim
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
MySQL Deployment
apiVersion: apps/v1
kind: Deployment
metadata:
name: mysql-deployment
labels:
app: mysql-deployment
spec:
selector:
matchLabels:
app: mysql-deployment
tier: mysql
strategy:
type: Recreate
template:
metadata:
labels:
app: mysql-deployment
tier: mysql
spec:
containers:
- image: mysql:5.6
name: mysql
env:
- name: MYSQL_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-secret
key: MYSQL_ROOT_PASSWORD
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 on your Spring application what you need to access to the database is :
Spring Boot deployment
apiVersion: apps/v1 # API version
kind: Deployment # Type of kubernetes resource
metadata:
name: order-app-server # Name of the kubernetes resource
labels: # Labels that will be applied to this resource
app: order-app-server
spec:
replicas: 1 # No. of replicas/pods to run in this deployment
selector:
matchLabels: # The deployment applies to any pods mayching the specified labels
app: order-app-server
template: # Template for creating the pods in this deployment
metadata:
labels: # Labels that will be applied to each Pod in this deployment
app: order-app-server
spec: # Spec for the containers that will be run in the Pods
imagePullSecrets:
- name: testXxxxxsecret
containers:
- name: order-app-server
image: XXXXXX/order:latest
ports:
- containerPort: 8080 # The port that the container exposes
env: # Environment variables supplied to the Pod
- name: MYSQL_ROOT_USERNAME # Name of the environment variable
valueFrom: # Get the value of environment variable from kubernetes secrets
secretKeyRef:
name: mysql-secret
key: MYSQL_ROOT_USERNAME
- name: MYSQL_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-secret
key: MYSQL_ROOT_PASSWORD
- name: MYSQL_ROOT_URL
valueFrom:
secretKeyRef:
name: mysql-secret
key: MYSQL_ROOT_PASSWORD
Create your Secret :
apiVersion: v1
kind: Secret
data:
MYSQL_ROOT_USERNAME: <BASE64-ENCODED-PASSWORD>
MYSQL_ROOT_URL: <BASE64-ENCODED-DB-NAME>
MYSQL_ROOT_USERNAME: <BASE64-ENCODED-DB-USERNAME>
MYSQL_ROOT_PASSWORD: <BASE64-ENCODED-DB-PASSWORD>
metadata:
name: mysql-secret
Spring Boot Service:
apiVersion: v1 # API version
kind: Service # Type of the kubernetes resource
metadata:
name: order-app-server-service # Name of the kubernetes resource
labels: # Labels that will be applied to this resource
app: order-app-server
spec:
type: LoadBalancer # The service will be exposed by opening a Port on each node and proxying it.
selector:
app: order-app-server # The service exposes Pods with label `app=polling-app-server`
ports: # Forward incoming connections on port 8080 to the target port 8080
- name: http
port: 8080