How to use the command 'podman image' (with examples)
This article provides examples and explanations for using the ‘podman image’ command to manage Docker images.
Command Description
The ‘podman image’ command is used to manage Docker images. It provides functionalities to list, delete, and view the history of local Docker images. This command is part of the Podman project, an open-source container engine that allows users to run and manage containers without requiring a daemon.
Use case 1: List local Docker images
Code:
podman image ls
Motivation: Listing the local Docker images can be useful to get an overview of the images available on a system. It allows users to quickly identify the images they have and their associated tags.
Explanation:
podman image ls- This command lists all the local Docker images.
Example output:
REPOSITORY TAG IMAGE ID CREATED SIZE
openshift/hello-openshift latest 0ba141a5e625 2 months ago 49.4MB
nginx latest 1c5fd32f9f69 2 months ago 133MB
alpine latest 6dbb9cc54074 3 months ago 5.6MB
Use case 2: Delete unused local Docker images
Code:
podman image prune
Motivation: Over time, local Docker images can accumulate and take up significant disk space. Removing unused images can free up disk space and improve system performance.
Explanation:
podman image prune- This command deletes unused local Docker images, removing any images that have no associated containers.
Example output:
Deleted Images:
deleted: sha256:c50ff23254d597f79619b4aaf9efdd83c6c39e838a3aaf2b6e82a140097dxx37
deleted: sha256:5waf34062341d6fdd90e89e1cd9baf6e6522f4fca276132075b64e09c3a55e27
Total reclaimed space: 2.6 MB
Use case 3: Delete all unused images (not just those without a tag)
Code:
podman image prune --all
Motivation: Sometimes, unused local Docker images can include both tagged and untagged images. The ‘–all’ option allows users to delete all unused images, regardless of whether they have tags.
Explanation:
--all- This option, when used with ‘podman image prune’, deletes all unused images, including both tagged and untagged images.
Example output:
Deleted Images:
deleted: sha256:2d5be105b65301341d6fdd90e89e1cd9baf6e6522f4fca276132075b64e09c3
Total reclaimed space: 2.5 MB
Use case 4: Show the history of a local Docker image
Code:
podman image history <image>
Motivation: Understanding the history of a Docker image can provide valuable insights into its creation and maintenance. It allows users to see the individual layers that make up the image and the commands used to build it.
Explanation:
<image>- This argument specifies the local Docker image for which the history is to be displayed.
Example output:
IMAGE ID CREATED CREATED BY SIZE COMMENT
c50ff23254d5 2 months ago /bin/sh -c #(nop) CMD ["/hello-openshift"] 0B
4d5b0875f808 2 months ago /bin/sh -c #(nop) EXPOSE 8080 0B
d96b1618eaff 2 months ago /bin/sh -c #(nop) ENTRYPOINT ["/hello-opens… 0B
2bb37f77f14c 2 months ago /bin/sh -c #(nop) COPY file:6308000e101fdc1… 49.4MB transferred 49.4MB in 0.5 seconds…
8c2e06607696 2 months ago /bin/sh -c #(nop) COPY --chown=1001:0 "hel… 48.6MB transferred 48.6MB in 1.0 seconds
884f47f13266 2 months ago /bin/sh -c #(nop) WORKDIR /tmp 0B
d28157f28828 2 months ago /bin/sh -c #(nop) LABEL io.openshift.non-sca… 0B
b04784f55149 2 months ago /bin/sh -c #(nop) COPY file:072c5caec6afc5c… 2.17MB transferred 2.17MB in 0.3 seconds…
50efb7ee0f92 2 months ago /bin/sh -c #(nop) COPY file:304a29b0c6b290d… 9.41MB transferred 9.41MB in 1.6 seconds…
b999774f38e1 2 months ago /bin/sh -c #(nop) COPY file:63422725d137b99… 39.5MB transferred 39.5MB in 1.0 seconds…
20be13e8d7b6 2 months ago /bin/sh -c #(nop) COPY dir:4be3cf28279911d2d… 0B copied 28 files and directories
475002e2df48 3 months ago /bin/sh -c #(nop) CMD ["/bin/sh"] 0B
Conclusion:
The ‘podman image’ command provides a variety of useful functionalities for managing Docker images. It allows users to list images, delete unused images, and view the history of images. By leveraging the power of this command, users can efficiently manage their Docker images and optimize system performance.
