how to link tomcat with mysql db container in kubernetes - docker

Question

My tomcat and mysql containers are not connecting.so how can I link them so that my war file can run succesfully.
I built my tomcat image using docker file
FROM picoded/tomcat7
COPY data-core-0.0.1-SNAPSHOT.war /usr/local/tomcat/webapps/data-core-0.0.1-SNAPSHOT.war
mysql.yaml
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
imagePullPolicy: "IfNotPresent"
env:
- name: MYSQL_ROOT_PASSWORD
value: root
- name: MYSQL_DATABASE
value: data-core
ports:
- containerPort: 3306
name: mysql
volumeMounts:
- name: mysql-persistent-storage
mountPath: /docker-entrypoint-initdb.d
volumes:
- name: mysql-persistent-storage
persistentVolumeClaim:
claimName: mysql-initdb-pv-claim
mysqlpersistantvolume.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: "/home/vignesh/stackoverflow/tmp/data" //this is the path were my
sql init script is placed.
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: mysql-initdb-pv-claim
labels:
app: mysql
spec:
storageClassName: manual
accessModes:
- ReadOnlyMany
resources:
requests:
storage: 1Mi
tomcat.yaml
apiVersion: v1
kind: Service
metadata:
name: tomcat
labels:
app: tomcat
spec:
type: NodePort
ports:
- name: http
port: 8080
targetPort: 8080
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: suji165475/vignesh:tomcatserver
name: tomcat
env:
- name: DB_PORT_3306_TCP_ADDR
value: mysql #service name of mysql
- name: DB_ENV_MYSQL_DATABASE
value: data-core
- name: DB_ENV_MYSQL_ROOT_PASSWORD
value: root
ports:
- containerPort: 8080
name: http
volumeMounts:
- name: tomcat-persistent-storage
mountPath: /var/data
volumes:
- name: tomcat-persistent-storage
persistentVolumeClaim:
claimName: tomcat-pv-claim
tomcatpersistantvolume.yaml
kind: PersistentVolume
apiVersion: v1
metadata:
name: tomcat-pv
labels:
type: local
app: mysql
spec:
storageClassName: manual
capacity:
storage: 1Mi
accessModes:
- ReadOnlyMany
hostPath:
path: "/app"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: tomcat-pv-claim
labels:
app: mysql
spec:
storageClassName: manual
accessModes:
- ReadOnlyMany
resources:
requests:
storage: 1Mi
currently using type:Nodeport for tomcat service. Do I have to use Nodeport for mysql also?? If so then should i give the same nodeport or different??
Note: Iam running all of this on a server using putty terminal

Answer 1

When kubetnetes start service, it adds env variables for host, port etc. Try using environment variable MYSQL_SERVICE_HOST