How to connect mysql kubernetes container internally with nodejs k8s container? - mysql

Question

I have created mysql k8s container and nodejs k8s container under same namespace.I can't able to connect mysql db.(sequalize)
I have tried to connect using '''http://mysql.e-commerce.svc.cluster.local:3306'''.But i got "SequelizeHostNotFoundError" error.
Here is my service and deployment yaml files.
kind: Service
metadata:
labels:
app: mysql
name: mysql
namespace: e-commerce
spec:
type: NodePort
ports:
- port: 3306
targetPort: 3306
nodePort: 30306
selector:
app: mysql
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: mysql
namespace: e-commerce
spec:
replicas: 1
template:
metadata:
labels:
app: mysql
spec:
containers:
- image: mysql:5.6
name: mysql-container
env:
- name: MYSQL_ROOT_PASSWORD
value: 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```

Answer 1

From the ClusterIP worked for me or better way to go with the host name of the local cluster service ex. db-mysql.default.svc.cluster.local. This way if you cluster restarts and your IP changes, then you got it covered.

Answer 2

You are trying to access database with http protocol, leave it or change with mysql://ip:3306. Some clients won't accept DNS name for databases so you can check ClusterIP of service and try that IP too.

Answer 3

As mentioned by community member FL3SH you can change your spec.type to clusterIP.
You can reproduce this task using stable helm chart wordpress/mysql.
For newly created pods:
mysql-mariadb-0
mysql-wordpress
and services:
mysql-mariadb
mysql-wordpress
After successfully deployment you can verify if your service is working from the mysql-wordpress pod by running:
kubectl exec -it mysql-wordpress-7cb4958654-tqxm6 -- /bin/bash
In addition, you can install additional tools like nslooukp, telnet:
apt-get update && apt-get install dnsutils telnet
Services and connectivity with db you can test by running f.e. those commands:
nslookup mysql-mariadb
telnet mysql-mariadb 3306
mysql -uroot -hmysql-mariadb -p<your_db_password>
example output:
nslookup mysql-mariadb
Server: 10.125.0.10
Address: 10.125.0.10#53
Non-authoritative answer:
Name: mysql-mariadb.default.svc.cluster.local
Address: 10.125.0.76
mysql -u root -hmysql-mariadb -p<your_db_password>
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 2068
Server version: 10.1.40-MariaDB Source distribution
You should be able to connect using service name or using ip address.
Inside this helm chart you can find also template for statefulset in order to create mysql pods.
Update
From the second pod f.e. ubuntu run this example - Node.js Mysql, install nodes.js and create connection to the database demo_db_connection.js
example:
var mysql = require('mysql');
var con = mysql.createConnection({
host: "mysql-mariadb",
user: "root",
password: "yourpassword"
});
con.connect(function(err) {
if (err) throw err;
console.log("Connected!");
});
run it:
root#ubuntu:~/test# node demo_db_connection.js
Connected!

Answer 4

Try with:
kind: Service
metadata:
labels:
app: mysql
name: mysql
namespace: e-commerce
spec:
clusterIP: None
type: ClusterIP
ports:
- port: 3306
targetPort: 3306
selector:
app: mysql
with the same connection string.