After successfully completing the work in this module you will be able to:
Explain container concepts.
Run containers using Podman.
Explore remote container registeries.
Manage the lifecycle of a container.
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Introduction to Containers
a container is an encapsulated process that includes the required runtime dependencies for the program to run. In a container, application-specific libraries are independent of the host operating system libraries.
Describing Containers
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Comparing Containers to Virtual Machines
Hypervisors, such as KVM, Xen, VMware, and Hyper-V, are applications that provide the virtualization functionality for VMs. The container equivalent of a hypervisor is a container engine, such as Podman.
Container images are a stable target for developers. Software applications require specific versions of libraries to be available for deployment, which can result in dependency issues or specific OS requirements. Because libraries are included in the container image, a developer can be confident of no dependency issues in a deployment.
Quiz
Introduction to Containers
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Creating Containers with Podman
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An Introduction to Podman
Podman is an open source tool that you can use to manage your containers locally.
[user@host ~]$ podman images
REPOSITORY TAG IMAGE ID CREATED SIZE
registry.redhat.io/rhel9/rhel-guest-image 9.4 52617ef413bd 2 weeks ago 216 MB
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Running and Displaying Containers
[user@host ~]$ podman run registry.redhat.io/rhel9/rhel-guest-image:9.4 \
echo 'Red Hat'
Red Hat
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Guided Exercise
Creating Containers with Podman
Use Podman to pull container images from a registry and to use them to run containers.
Container Image Registries
A container image is a packaged version of your application, with all the dependencies that are necessary for the application to run. You can use image registries to store container images to later share them in a controlled manner.
Quay.io
you can use the Quay.io registry to store your custom images.
Guided Exercise
Container Image Registries
Use Podman to pull container images from a registry, and use the images to run containers.
Managing the Container Lifecycle
Podman provides a set of subcommands to create and manage containers. You can use those subcommands to manage the container and container image lifecycle.
Guided Exercise
Managing the Container Lifecycle
Use Podman to pull container images from a registry, and use the images to run containers.
A container is an encapsulated process that includes the required runtime dependencies for the program to run.
Registries are used to store container images to later share them in a controlled manner.
Containers are ephemeral by default, which means that the container engine removes the writable layer when you remove the container.
Hypervisors are applications that provide the virtualization functionality for virtual machines. The container equivalent of a hypervisor is a container engine, such as Podman.
Podman, which Red Hat Enterprise Linux provides, is a container engine that directly runs and manages container instances and container images on a single host.
With Podman, you can find, run, build, or deploy OCI (Open Container Initiative) containers and container images. By default, Podman is daemonless.
As a regular user, you can create systemd unit files to manage your rootless containers.
Graded Lab
Run Containers
Use podman to pull a container image from a registry, and use the image to run a detached container.
