Step1:finish installing etcd and kubernetes with YUM in CentOS7 and shutdown firewall
Step2:modify related configuration item in /etc/sysconfig/docker
OPTIONS='--selinux-enabled=false --insecure-registry gcr.io'
Step3:modify related configuration item in /etc/kubernetes/apiserver
remove
ServiceAccount
in KUBE_ADMISSION_CONTROL configuration item
Step4:start all the related services of etcd and kubernetes
Step5:start ReplicationController for mysql db
kubectl create -f mysql-rc.yaml
apiVersion: v1
kind: ReplicationController
metadata:
name: mysql
spec:
replicas: 1
selector:
app: mysql
template:
metadata:
labels:
app: mysql
spec:
containers:
- name: mysql
image: hub.c.163.com/library/mysql
ports:
- containerPort: 3306
env:
- name: MYSQL_ROOT_PASSWORD
value: "123456"
Step6:start related mysql db service
kubectl create -f mysql-svc.yaml
kind: Service
metadata:
name: mysql
spec:
ports:
- port: 3306
selector:
app: mysql
Step7:start ReplicationController for myweb
kubectl create -f myweb-rc.yaml
apiVersion: v1
kind: ReplicationController
metadata:
name: myweb
spec:
replicas: 3
selector:
app: myweb
template:
metadata:
labels:
app: myweb
spec:
containers:
- name: myweb
image: docker.io/kubeguide/tomcat-app:v1
ports:
- containerPort: 8080
env:
- name: MYSQL_SERVICE_HOST
value: "mysql"
- name: MYSQL_SERVICE_PORT
value: "3306"
Step8:start related tomcat service
kubectl create -f myweb-svc.yaml
apiVersion: v1
kind: Service
metadata:
name: myweb
spec:
type: NodePort
ports:
- port: 8080
nodePort: 30001
selector:
app: myweb
When I visit from browser with nodeport(30001),I get the following Exception:
Error:com.mysql.jdbc.exceptions.jdbc4.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.
kubectl get ep
NAME ENDPOINTS AGE
kubernetes 192.168.57.129:6443 1d
mysql 172.17.0.2:3306 1d
myweb 172.17.0.3:8080,172.17.0.4:8080,172.17.0.5:8080 1d
kubectl get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes 10.254.0.1 <none> 443/TCP 1d
mysql 10.254.0.5 <none> 3306/TCP 1d
myweb 10.254.220.2 <nodes> 8080:30001/TCP 1d
From the interior of any tomcat container I can see the mysql env and the related mysql link code in JSP is as below:
Class.forName("com.mysql.jdbc.Driver");
String ip=System.getenv("MYSQL_SERVICE_HOST");
String port=System.getenv("MYSQL_SERVICE_PORT");
ip=(ip==null)?"localhost":ip;
port=(port==null)?"3306":port;
System.out.println("Connecting to database...");
conn = java.sql.DriverManager.getConnection("jdbc:mysql://"+ip+":"+port+"?useUnicode=true&characterEncoding=UTF-8", "root","123456");
[root@promote ~]# docker exec -it 1470cfaa1b1c /bin/bash
root@myweb-xswfb:/usr/local/tomcat# env |grep MYSQL_SERVICE
MYSQL_SERVICE_PORT=3306
MYSQL_SERVICE_HOST=mysql
root@myweb-xswfb:/usr/local/tomcat# ping mysql
ping: unknown host
Can someone tell me why I could not ping mysqldb hostname from inner tomcat server?Or how to locate the problem further?
