Kubernetes - NodeJs MySQL pod does not connect with MySQL pod - mysql

Question

I have a MySQL pod up and running. I opened a terminal for this pod and created a database and a user.
create database demodb;
create user demo identified by 'Passw0rd';
grant all on demodb.* to 'demo';
I have this Deployment to launch a NodeJs client for the MySQL pod. This is on my local minikube installation.
apiVersion: apps/v1
kind: Deployment
metadata:
name: demos
spec:
selector:
matchLabels:
app: demos
template:
metadata:
labels:
app: demos
spec:
containers:
- name: demo-db
image: 172.30.1.1:5000/demo/db-demos:0.1.0
resources:
limits:
memory: "128Mi"
cpu: "200m"
ports:
- containerPort: 4000
name: probe-port
---
apiVersion: v1
kind: Service
metadata:
name: demos
spec:
selector:
app: demos
ports:
- name: probe-port
port: 4001
targetPort: probe-port
The Dockerfile for the image passes the environment variables for the NodeJs client to use.
FROM node:alpine
ADD . .
RUN npm i
WORKDIR /app
ENV PROBE_PORT 4001
ENV MYSQL_HOST "mysql.demo.svc"
ENV MYSQL_PORT "3306"
ENV MYSQL_USER "demo"
ENV MYSQL_PASSWORD "Passw0rd"
ENV MYSQL_DATABASE "demodb"
CMD ["node", "index.js"]
And, the NodeJs client connects as follows.
const mysql = require('mysql')
const connection = mysql.createConnection({
host: process.env.MYSQL_HOST,
port: process.env.MYSQL_PORT,
user: process.env.MYSQL_USER,
password: process.env.MYSQL_PASSWORD,
database: process.env.MYSQL_DATABASE
});
connection.connect((err) => {
if (err) {
console.log('Database connection failed. ' + err.message)
} else {
console.log('Database connected.')
}
});
The database connection keeps failing with a message as Database connection failed. connect ENOENT tcp://172.30.88.64:3306. The TCP/IP address shown in this message is correct i.e. it matches with the service mysql.demo.svc of the running MySQL pod.
In the MySQL configuration files, I don't see bind-address. This should mean that, MySQL should accept connections from 'every where'. I am creating the user without the location qualifier i.e. the user is 'demo'#'%'. The connection is, obviously, not through sockets as I am passing the host and port values for connection.
What am I missing?

Answer 1

I got it working as follows.
const mysql = require('mysql')
const connection = mysql.createConnection({
host: process.env.MYSQL_HOST,
// port: process.env.MYSQL_PORT,
user: process.env.MYSQL_USER,
password: process.env.MYSQL_PASSWORD,
database: process.env.MYSQL_DATABASE
});
connection.connect((err) => {
if (err) {
console.log('Database connection failed. ' + err.message)
} else {
console.log('Database connected.')
}
});
That's right; I removed the port number from the option. :rolleyes: This example from RedHat is closest I have seen.
Also, I created the user with mysql_native_password as that is the only plugin mechanism that is supported by NodeJs client. See here.