How to install Podman on Ubuntu?. Podman (Pod Manager) is a tool used to create and maintain containers. It is part of the libpod library. The Red Hat team has been working on a set of tools for running containers without a daemon. Did you know you can’t run Docker containers without Docker Engine daemon?.

The following set of tools work together to power the use of Containers without an all-time running daemon process.

  • Buildah to facilitate building of OCI images
  • Skopeo for sharing/finding container images on Docker registries, the Atomic registry, private registries, local directories and local OCI-layout directories.
  • Podman for running containers without need for daemon.

Buildah’s commands replicate all of the commands that are found in a Dockerfile. Buildah containers are just created to allow content to be added back to the container image.

Podman gives you all the commands and functions required to maintain and modify OCI images, such as pulling and tagging. It also allows you to create, run, and maintain containers created from those images.

How to Install Podman on Ubuntu

The podman package is on a PPA repository which needs to be added prior to installation. Start a new terminal session on your Ubuntu machine and run commands below.

sudo apt update
sudo apt -y  install software-properties-common
sudo add-apt-repository -y ppa:projectatomic/ppa

Once the repository is added, proceed to install Podman.

sudo apt update
sudo apt -y install podman

After the installation, you can display information pertaining to the host, current storage stats, and build of podman.

# podman  info
host:
  BuildahVersion: 1.7-dev
  Conmon:
    package: 'cri-o-1.12: /usr/lib/crio/bin/conmon'
    path: /usr/lib/crio/bin/conmon
    version: 'conmon version 1.12.4-dev, commit: '
  Distribution:
    distribution: ubuntu
    version: "18.04"
  MemFree: 720404480
  MemTotal: 1033080832
  OCIRuntime:
    package: 'cri-o-runc: /usr/sbin/runc'
    path: /usr/sbin/runc
    version: 'runc version spec: 1.0.1-dev'
  SwapFree: 2047864832
  SwapTotal: 2047864832
  arch: amd64
  cpus: 2
  hostname: ubuntu-01
  kernel: 4.15.0-42-generic
  os: linux
  rootless: false
  uptime: 2m 5.03s
insecure registries:
  registries: []
registries:
  registries:
  - docker.io
  - registry.fedoraproject.org
  - quay.io
  - registry.access.redhat.com
  - registry.centos.org
store:
  ConfigFile: /etc/containers/storage.conf
  ContainerStore:
    number: 1
  GraphDriverName: overlay
  GraphOptions: null
  GraphRoot: /var/lib/containers/storage
  GraphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Using metacopy: "false"
  ImageStore:
    number: 2
  RunRoot: /var/run/containers/storage

Populate configuration files

We need to manually add configuration files such as ones for registry and policy.

sudo mkdir -p /etc/containers
sudo curl https://raw.githubusercontent.com/projectatomic/registries/master/registries.fedora -o /etc/containers/registries.conf
sudo curl https://raw.githubusercontent.com/containers/skopeo/master/default-policy.json -o /etc/containers/policy.json

Test Podman installation on Ubuntu

Pull Alpine docker image.

$ podman pull alpine
Trying to pull docker.io/library/alpine…Getting image source signatures
Copying blob 8e402f1a9c57: 2.63 MiB / 2.63 MiB [=======================] 5s
Copying config 5cb3aa00f899: 1.48 KiB / 1.48 KiB [=====================] 0s
Writing manifest to image destination
Storing signatures
5cb3aa00f89934411ffba5c063a9bc98ace875d8f92e77d0029543d9f2ef4ad0

List Downloaded images

$ podman  images
REPOSITORY                      TAG      IMAGE ID       CREATED        SIZE
docker.io/library/alpine        latest   5cb3aa00f899   3 days ago     5.79 MB
docker.io/library/hello-world   latest   fce289e99eb9   2 months ago   5.62 kB

Podman’s local repository is in /var/lib/containers

Run container with command – command options similar to docker.

$ podman  run -it  --rm docker.io/library/alpine /bin/sh
/ # apk update
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz
v3.9.2-1-g592d872fb8 [http://dl-cdn.alpinelinux.org/alpine/v3.9/main]
v3.9.2-2-ge7dc3349a9 [http://dl-cdn.alpinelinux.org/alpine/v3.9/community]
OK: 9754 distinct packages available

/ # apk add vim
 (1/5) Installing lua5.3-libs (5.3.5-r1)
 (2/5) Installing ncurses-terminfo-base (6.1_p20190105-r0)
 (3/5) Installing ncurses-terminfo (6.1_p20190105-r0)
 (4/5) Installing ncurses-libs (6.1_p20190105-r0)
 (5/5) Installing vim (8.1.0630-r0)
 Executing busybox-1.29.3-r10.trigger
 OK: 40 MiB in 19 packages
 / # exit

Show running containers.

$ podman ls
CONTAINER ID  IMAGE                            COMMAND  CREATED        STATUS            PORTS  NAMES
1eb35f1b7de8  docker.io/library/alpine:latest  /bin/sh  4 seconds ago  Up 4 seconds ago         pedantic_roentgen
ec9c5b12db46  docker.io/library/alpine:latest  /bin/sh  5 minutes ago  Up 5 minutes ago         ecstatic_wiles

Conclusion

Podman seems to be a replacement for Docker and other container management tools which require a daemon to work. It is still fresh and in early development stages to tell a lot. In RHEL 8, the officially supported tools for managing Docker containers are Podman and Buildah.

Related guides:

How To Install Podman on Debian

How To Install Podman on Arch Linux / Manjaro

How To Install Podman on CentOS & Fedora

How to Install and use Packer on Ubuntu

How to Setup Docker Private Registry on Ubuntu 

How to setup 3 node Kubernetes Cluster on Ubuntu 18.04 with Weave Net CNI

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