Customizing Container Images Using Podman and Buildah on RHEL

We're going to use the following criteria to build a custom container image, using Buildah and a Dockerfile:

• Based on the fedora:latest container image
• Maintainer=“[email protected]”
• Install httpd in the container
  • Clean up after install
• Create five test text files in /var/www/html
  • Contents should be "Test File (1-5)"
  • Filenames should be "test(1-5).txt"
• Expose port 80
• Run our httpd service using "/usr/sbin/httpd -D FOREGROUND"
• Name our image my-fedora-httpd:latest

Instructions:

First create a Dockerfile based on the above criteria, then use buildah bud to build a container image from the Dockerfile. Next, launch five containers `my-fedora-httpd-(1-5) and test with curl. Make sure you can retrieve any of the test files (test(1-5).txt) from any of the containers.

When testing is successful, clean up all your containers and images.

We're going to use the following criteria to build a custom container image, using Buildah Native Commands:

• Based on the fedora:latest container image.
• Maintainer=[email protected]”
• Install httpd in the container.
  • Clean up after install.
• Create five test text files in /var/www/html.
  • Contents should be Test File (1-5).
  • Filenames should be test(1-5).txt.
• Expose port 80.
• Run our httpd service using "/usr/sbin/httpd -D FOREGROUND".
• Name our image my-fedora-httpd:latest.

Instructions:

Build a container image using the above description using buildah native commnads. Next, launch five containers `my-fedora-httpd-(1-5) and test with curl. Make sure you can retrieve any of the test files (test(1-5).txt) from any of the containers.

A local container image registry has been pre-configured on your server. Before we can use it, we need to start it. A script (registry.sh) has been provided in the cloud_user home directory. You will need to run this script with sudo, as it requires root privilages.

Let's explore the ways we can manage containers and images using buildah!

General Buildah Commands:

Perform the following:

• View the help information for the buildah command.
  • View the help information for the buildah help command.
• View the man page for the buildah command.
• Display information for the buildah system.
• Diplay information about the localhost/my-fedora-httpd container image.
• Check the version of buildah.

Content Management Using Buildah:

Perform the following:

• Create a directory ~/testfiles and add some test files to it using the for i inseq 1 5; do echo "Add Test File "$i > ~/testfiles/add$i.txt ; echo "Copy Test File "$i > ~/testfiles/copy$i.txt ; done command.
  • View the contents of the files to verify them.
• View the help information for the buildah add and buildah copy commands.
• Create a new intermediate container using the fedora:latest container image.
• Use buildah to list its containers.
• Transfer the files you created into the /var/www/html/ directory of the intermediate container you created.
  • Transfer the add(1-5).txt files using buildah add command.
  • Transfer the copy(1-5).txt files using the buildah copy command.

Filesystem Management Using Buildah:

Perform the following:

• Run your commands using a modified user namespace.
• Mount the intermediate container's filesystem.
• Check for our newly transferred files.
  • Use ls.
  • View the contents of the files.
• Unmount the intermediate container's filesystem.
• Exit the modified user namespace.

Image Management Using Buildah:

Perform the following:

• List our container images using buildah.
• Use buildah to log in to our local container registry at https://localhost:5000.
  • Username: cloud_user
  • Password: Enter the password provided by the lab credentials.
• Push our localhost/my-fedora-httpd:latest container image to the local container registry.
• Check our work using curl -u cloud_user:registry https://localhost:5000/v2/_catalog.
• List our local container images using buildah.
• Remove the localhost/my-fedora-httpd:latest container image from our local storage (not the local container registry!).
• List our local container images using buildah again.
• Pull the localhost/my-fedora-httpd:latest container image from the local container registry.
• List our local container images using buildah again.
• Add a tag for our my-fedora-httpd:latest image.
  • Make the tag ourcustomwebserver:latest.
• List our local container images using buildah again.
• Log out of our local container image registry.

Container Management Using Buildah:

Perform the following:

• Diplay a list of containers using buildah.
• Use buildah to rename the intermediate working container to my-container.
• Diplay a list of containers using buildah again.
• Remove the my-container container using buildah.
• Diplay a list of containers using buildah again.

Great work, Cloud Gurus!