Demo Image Creation Docker Commit Method

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1. Pull the CentOS 7 Base Image

docker image pull centos:7

7: Pulling from library/centos
75f829a71a1c: Pull complete
Digest: sha256:19a79828ca2505eae0ff38c2f39901f4826737295157cc5212b7a372cd2b
Status: Downloaded newer image for centos:7
docker.io/library/centos:7

docker image ls

REPOSITORY   TAG   IMAGE ID       CREATED        SIZE
centos       7     7e6257c9f8d8   2 months ago   203MB

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2. Create and Start a Container

1. Create a container named test from the CentOS 7 image:
   docker container create --name test centos:7
   
2. Start it:
   docker container start test
   
3. Attach an interactive shell:
   docker container exec -it test /bin/bash
   

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3. Install HTTPD and Customize the Web Page

yum -y update
yum install -y httpd
echo "<h1>Hello from KodeKloud</h1>" > /var/www/html/index.html

httpd -k start
curl http://localhost
httpd -k stop

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4. Commit the Container to a New Image

1. Exit and stop the container:
   exit
   docker container stop test
   
2. Review container status:
   docker container ls -l
   
3. Commit with metadata and a default CMD. Here’s an overview of common flags:

4. Run docker commit:
   docker container commit \
     -a "Yogesh Raheja" \
     -m "Add HTTPD and custom index" \
     -c 'CMD ["httpd", "-D", "FOREGROUND"]' \
     test webtest:v1
   

sha256:9cd11553a2e7...

docker image ls

REPOSITORY   TAG   IMAGE ID       CREATED         SIZE
webtest      v1    9cd11553a2e7   30 seconds ago  328MB
centos       7     7e6257c9f8d8   2 months ago    203MB

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5. Test Your Custom Image

docker container run -d --name webtesting -p 80:80 webtest:v1

docker container ls -l

Hello from KodeKloud

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6. Tag and Push to Docker Hub

1. Tag the image for your repository (replace <your-dockerhub-username>):
   docker image tag webtest:v1 <your-dockerhub-username>/codekloud-webtest:v1
   
2. Log in to Docker Hub:
   docker login
   
3. Push the tagged image:
   docker push <your-dockerhub-username>/codekloud-webtest:v1
   

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References

• Docker Commit Documentation
• Docker Image Best Practices
• CentOS on Docker Hub