how to access to a remote MySQL database from a nodejs app inside a kubernetes pod?

Question

I have created a POD that contains a nodejs app from which I'm trying to connect to a remote database in another server. My POD configuration goes like this:

apiVersion : "v1"
kind : "Service"
metadata :
  name : "mysql"
spec :
  ports :
    -
      name : "mysql"
      protocol : "TCP"
      port : 3306
      targetPort : 3306
      nodePort : 0
---
kind: "Endpoints"
apiVersion: "v1"
metadata:
  name: "mysql"
subsets:
  -
    addresses:
      -
        ip: "xxx.xxx.xxx.xxx" #The IP Address of the external web server
    ports:
      -
        port: 3306
        name: "mysql"
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: productos
  labels:
    app: productos
spec:
  replicas: 3
  selector:
    matchLabels:
      app: productos
      tier: backend
  strategy:
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: productos
        tier: backend
    spec:
      restartPolicy: Always
      containers:
      - image: sospinah/tutorial:lopido-ms-productos6
        name: productos
        env:
        - name: MYSQL_HOST
          value: "mysql.default.svc.cluster.local"
        - name: MYSQL_USER
          value: "<username>"
        - name: MYSQL_DATABASE
          value: "<dbname>"
        - name: MYSQL_PASSWORD
          value: "<password>"
        ports:
        - containerPort: 4000

In my nodejs application I have defined my database connection as follows:

const connection = mysql.createConnection({
        host: process.env.MYSQL_HOST,
        user: process.env.MYSQL_USER,
        password: process.env.MYSQL_PASSWORD,
        database: process.env.MYSQL_DATABASE,
});

And I'm getting a timeout error on app startup

> [email protected] start /usr/src/app
> node index.js

server listening at port 0.0.0.0:4000
error connecting mysql:  { Error: connect ETIMEDOUT
    at Connection._handleConnectTimeout (/usr/src/app/node_modules/mysql/lib/Connection.js:419:13)
    at Object.onceWrapper (events.js:313:30)
    at emitNone (events.js:106:13)
    at Socket.emit (events.js:208:7)
    at Socket._onTimeout (net.js:422:8)
    at ontimeout (timers.js:498:11)
    at tryOnTimeout (timers.js:323:5)
    at Timer.listOnTimeout (timers.js:290:5)
    --------------------
    at Protocol._enqueue (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:145:48)
    at Protocol.handshake (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:52:23)
    at Connection.connect (/usr/src/app/node_modules/mysql/lib/Connection.js:130:18)
    at Object.bdConfig.testConection (/usr/src/app/database/config.js:16:23)
    at Object.<anonymous> (/usr/src/app/index.js:18:14)
    at Module._compile (module.js:653:30)
    at Object.Module._extensions..js (module.js:664:10)
    at Module.load (module.js:566:32)
    at tryModuleLoad (module.js:506:12)
    at Function.Module._load (module.js:498:3)
  errorno: 'ETIMEDOUT',
  code: 'ETIMEDOUT',
  syscall: 'connect',
  fatal: true }

I would like to know what am I missing in my POD configuration and/or application configuration.

I'm guessing you found a solution to this problem. I have the exact issue. Can you share your solution? — Ralph
– Ralph, Commented Oct 23, 2021 at 23:18

P Ekambaram · Accepted Answer · 2019-06-26 06:19:59Z

1

you have defined mysql host as mysql.default.svc.cluster.local

This would work if both nodejs and mysql run in same kubernetes cluster.

answered Jun 26, 2019 at 6:19

P Ekambaram

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3 Comments

Sebastian Ospina Over a year ago

Thank you very much for the answer, but I still can not connect my pod with a database hosted on another server.

P Ekambaram Over a year ago

where is the database running? on vm or in a pod?

Sebastian Ospina Over a year ago

the database is in a MV

Harsh Manvar · Accepted Answer · 2019-06-26 09:06:31Z

1

You can use service name to connect pods internally. you can use 'mysql' service name if your webserver is running inside same kubernetes cluster.

If you want to run your mysql inside kubernetes cluster and want to make connection outside of kubenetes cluster then probably you can expose your mysql service to internet and you can to your mysql database from anywhere. If your all application running inside same cluster then use a service name to resolve the address.

answered Jun 26, 2019 at 9:06

Harsh Manvar

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17 Comments

Sebastian Ospina Over a year ago

Can you please explain how to connect the pod to a database that is on external server. Thank you so much

Sebastian Ospina Over a year ago

Yes of course I'm passing the credentials of the database but I still rejects the connection. the database and the kubernetes cluster is located on a private LAN I believe that the conflict is generated because the host ip with which nodejs rises is removed from the LAN?

Sebastian Ospina Over a year ago

Database runs on? do you mean the engine or the server (MV)?

Sebastian Ospina Over a year ago

the database is in an MV

Sebastian Ospina Over a year ago

sorry, it's virtual machine

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