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Posted on Sep 26

Kubernetes - Day - 07 - Questions Docker ( 1 to 6 )

#kubernetes #devops #docker #tutorial

1 . Install Docker on your local machine. Verify the installation by running the hello-world container.

  docker pull hello-world
  docker run hello-world
  docker ps -a
  docker logs 030152e160a9

2. Pull the nginx image from Docker Hub and run it as a container. Map port 80 of the container to port 8080 of your host.

docker pull nginx
docker run -d -p 8080:80 --name nginx_test nginx

3. Create a Dockerfile for a simple Node.js application that serves “Hello World” on port 3000. Build the Docker image with tag my-node-app and run a container. Below is the sample index.js file.

const express = require('express');
const app = express();

app.get('/', (req, res) => {
res.send('Hello World');
});

app.listen(3000, () => {
console.log('Server is running on port 3000');
});

--> what is docker file ? - A Docker-file is a plain text file that contains a step-by-step set of instructions used to build a Docker image.
-- > It acts as the blueprint or recipe for your application.

Alpine is the OS (Operating System). It acts as the very thin, lightweight floorboards at the bottom of the container.
Node.js Engine sits on top of Alpine to read and execute your JavaScript files.
NPM (Node Package Manager) is the tool built into Node.js that goes out to the internet to download extra libraries (like express).

    docker build -t my-node-app .
    docker ps
    docker ps -a
    docker run -d -p 3000:3000 --name my-node-app my-node-app
    docker ps -a
    docker ps

4. Tag the Docker image my-node-app from Task 3 with a version tag v1.0.0.

docker tag my-node-app my-node-app:v1.0.0

5. Push the tagged image from Task 4 to your Docker Hub repository.

    docker login
    docker login -u sathishpy1808
    docker tag my-node-app my-node-app:v1.0.0
    docker images
    docker tag my-node-app:v1.0.0 sathishpy1808/my-node-app:v1.0.0
    docker push sathishpy1808/my-node-app:v1.0.0

6. Run a container from the ubuntu image and start an interactive shell session inside it. You can run commands like ls, pwd, etc.

docker pull ubuntu
docker run -it ubuntu bash

Notes

docker ps -a --> shows all containers which are also stopped
docker ps --> only running containers.

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