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

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```

please share with your results - did try the solution below? — Mark
– Mark, Commented Aug 16, 2019 at 11:57
Hi Mithun, It would be nice to upvote/accept the most useful answer in the thread. stackoverflow.com/help/someone-answers — Black_Bacardi
– Black_Bacardi, Commented Aug 20, 2019 at 10:47

Gajen Sunthara · Accepted Answer · 2019-11-26 18:45:12Z

2

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.

edited Nov 26, 2019 at 18:45

answered Nov 22, 2019 at 21:22

Gajen Sunthara

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1 Comment

nyoto arif Over a year ago

can you please point to a doc explaining about this db-mysql.default.svc.cluster.local more in detail?

Akin Ozer · Accepted Answer · 2019-08-12 19:58:12Z

1

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.

answered Aug 12, 2019 at 19:58

Akin Ozer

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Comments

Mark · Accepted Answer · 2019-08-13 15:26:54Z

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!

FL3SH · Accepted Answer · 2019-08-12 18:34:48Z

0

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.

answered Aug 12, 2019 at 18:34

FL3SH

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7 Comments

FL3SH Over a year ago

Are you sure that connection url is correct - I mean the syntax? Try with just service name so url will be `mysql:3306'

Mithun Over a year ago

Curl command inside nodejs container also not helps.Its in KIND(kubernetes in Docker)

Mithun Over a year ago

when I tried the wget command inside nodejs container.--> Connecting to mysql:3306 (10.244.0.4:3306) wget: bad header line: 5.6.45

FL3SH Over a year ago

Now try to install mysql client in nodejs container and connect to the database.

Mithun Over a year ago

Before I used node:10-alpine image as base image of my node cont..Now I changed to node:10.14.2..I got 5.6.45o%cHzQf/??Q.1Kf>Aju.!Zmysql_native_password!??#08S01Got packets out of order when i put curl sql string.

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