This guide will discuss how to install Podman on CentOS 7 / Fedora 31/30/29. Podman is a daemonless container engine for developing, managing, and running OCI Containers on your Linux System. The major difference between Docker and Podman is that there is no daemon in Podman.
For Ubuntu, check: How to install podman on Ubuntu
Podman uses container runtimes as well for example runc but the launched containers are direct descendants of the podman process. This kind of architecture has its advantages such as the following:
- Applied Cgroups or security constraints still control the container: Whatever cgroup constraints you apply on the podman command, the containers launched will receive those same constraints directly.
- Advanced features of systemd can be utilized using this model: This can be done by placing podman into a systemd unit file and hence achieving more.
The following set of tools work together to power the use of Containers without an all-time running daemon process.
- Buildah to facilitate the 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 the need for a daemon.
Install Podman on CentOS 7 / Fedora 31/30/29
The podman package is available on Fedora & CentOS upstream repositories.
--------- CentOS -------------- $ sudo yum -y install podman ---------- Fedora -------------- $ sudo dnf install -y podman
To view installed package details, use rpm command.
$ rpm -qi podman Name : podman Version : 0.12.1.2 Release : 2.git9551f6b.el7.centos Architecture: x86_64 Install Date: Sat 15 Jun 2019 01:43:33 PM EAT Group : Unspecified Size : 33654116 License : ASL 2.0 Signature : RSA/SHA256, Wed 13 Feb 2019 11:56:49 PM EAT, Key ID 24c6a8a7f4a80eb5 Source RPM : podman-0.12.1.2-2.git9551f6b.el7.centos.src.rpm Build Date : Wed 13 Feb 2019 08:05:29 PM EAT Build Host : x86-02.bsys.centos.org Relocations : (not relocatable) Packager : CentOS BuildSystem http://bugs.centos.org Vendor : CentOS URL : https://github.com/containers/libpod Summary : Manage Pods, Containers and Container Images Description : Manage Pods, Containers and Container Images libpod provides a library for applications looking to use the Container Pod concept popularized by Kubernetes.
After the installation, you can display information pertaining to the host, current storage stats, and build of podman.
$ podman info
host:
BuildahVersion: 1.6-dev
Conmon:
package: podman-0.12.1.2-2.git9551f6b.el7.centos.x86_64
path: /usr/libexec/podman/conmon
version: 'conmon version 1.12.0-dev, commit: b909c9e1a3e8f14d5694a118fb9c0c0325a31d4f-dirty'
Distribution:
distribution: '"centos"'
version: "7"
MemFree: 461684736
MemTotal: 3872858112
OCIRuntime:
package: runc-1.0.0-59.dev.git2abd837.el7.centos.x86_64
path: /usr/bin/runc
version: 'runc version spec: 1.0.0'
SwapFree: 0
SwapTotal: 0
arch: amd64
cpus: 2
hostname: techwiz-app-server
kernel: 3.10.0-957.10.1.el7.x86_64
os: linux
rootless: false
uptime: 831h 27m 5.82s (Approximately 34.62 days)
insecure registries:
registries: []
registries:
registries:
- registry.access.redhat.com
- docker.io
- registry.fedoraproject.org
- quay.io
- registry.centos.org
store:
ContainerStore:
number: 0
GraphDriverName: overlay
GraphOptions:
- overlay.override_kernel_check=true
GraphRoot: /var/lib/containers/storage
GraphStatus:
Backing Filesystem: extfs
Native Overlay Diff: "true"
Supports d_type: "true"
ImageStore:
number: 0
RunRoot: /var/run/containers/storage
Try pull alpine Linux image.
$ podman pull alpine Trying to pull registry.access.redhat.com/alpine:latest...Failed Trying to pull docker.io/alpine:latest...Getting image source signatures Copying blob sha256:e7c96db7181be991f19a9fb6975cdbbd73c65f4a2681348e63a141a2192a5f10 2.63 MB / 2.63 MB [========================================================] 0s Copying config sha256:055936d3920576da37aa9bc460d70c5f212028bda1c08c0879aedf03d7a66ea1 1.48 KB / 1.48 KB [========================================================] 0s Writing manifest to image destination Storing signatures 055936d3920576da37aa9bc460d70c5f212028bda1c08c0879aedf03d7a66ea1
Check list of downloaded images.
$ podman images REPOSITORY TAG IMAGE ID CREATED SIZE docker.io/library/alpine latest 055936d39205 5 weeks ago 5.8 MB
Using Podman on CentOS 7 / Fedora 31/30/29
Now that you have installed podman on CentOS 7 & Fedora system, the next reading is on how to use it. We have a guide for this:
How To run Docker Containers using Podman and Libpod
Setup Docker Container Registry with Podman & Let’s Encrypt SSL
Conclusion
Podman shows a lot of promise in the future of Containerization. In fact, Red Hat did not just remove the Docker container engine from OpenShift. It also removed the Docker container engine, along with the docker command, from Red Hat Enterprise Linux 8 entirely. Thank you for reading through.
Also check:
How to Setup Docker Private Registry on Fedora / CentOS
Best Storage Solutions for Kubernetes & Docker Containers
How to Install Docker on CentOS / Fedora
How to run Local Openshift Cluster with Minishift
Deploy Lightweight Kubernetes with MicroK8s and Snap
