Podman is an alternative to Docker, providing a similar interface. It supports rootless containers and a shim service for docker-compose.
For container networking, install.
If you want to replace Docker, one can install to mimic the docker binary along with man pages.
By default it is only possible to run Podman containers as root. See #Rootless Podman to set up running containers as a non-root user.
Configuration files for configuring how containers behave are located at
/usr/share/containers/. You must copy necessary files to
/etc/containers before edit. To configure the network bridge interface used by Podman see
CONFIG_USER_NS_UNPRIVILEGED) which has some serious security implications, see Security#Sandboxing applications for details.
By default only
root is allowed to run containers (or namespaces in kernelspeak). Running rootless Podman improves security as an attacker will not have root privileges over your system, and also allows multiple unprivileged users to run containers on the same machine. See also .
The following packages are required to run Podman in a rootless environment:
First, check the value of
kernel.unprivileged_userns_clone by running:
$ sysctl kernel.unprivileged_userns_clone
Set subuid and subgid
In order for users to run rootless Podman, a
/etc/subgid which lists the UIDs for their user namespace.
/etc/subgid do not exist by default; see FS#68741. The usermod command does not create the files, so they need to be created manually first:
# touch /etc/subuid /etc/subgid # chmod 644 /etc/subuid /etc/subgid
The following command enables the
username user and group to run Podman containers (or other types of containers in that case). It allocates a given range of UIDs and GIDs to the given user and group.
# usermod --add-subuids 100000-165535 --add-subgids 100000-165535 username
Now, you should have the following content (replacing
username with the given username):
- Many images require 65536 uids / gids for mapping (notably the base busybox and alpine images). It is recommended that you allocate at least that many uids / gids for each user to maximize compatibility with docker.
- If you are using systemd-homed, the minimum UID and GID for containers must be at least 524288 (check the "begin container users" value in the output of
Propagate changes to subuid and subgid
Rootless Podman uses a pause process to keep the unprivileged namespaces alive. This prevents any change to the
/etc/subgid files from being propagated to the rootless containers while the pause process is running. For these changes to be propagated it is necessary to run:
$ podman system migrate
After this, the user/group specified in the above files is able to start and run Podman containers.
The configuration for how and where container images and instances are stored takes place in
$XDG_CONFIG_HOME/containers/storage.confon a per-user basis.
driver according to the filesystem in use for the storage location (see ).
Podman is able to run images built for different CPU architecture than host using Wikipedia:binfmt_misc system.
To enable it, install.
systemd comes with
systemd-binfmt.service service which should enable new rules.
Verify that binfmt rules have been added:
$ ls /proc/sys/fs/binfmt_misc
DOSWin qemu-cris qemu-ppc qemu-sh4eb status qemu-aarch64 qemu-m68k qemu-ppc64 qemu-sparc qemu-alpha qemu-microblaze qemu-riscv64 qemu-sparc32plus qemu-arm qemu-mips qemu-s390x qemu-sparc64 qemu-armeb qemu-mipsel qemu-sh4 register
Podman should now be able to run foreign architecture images. Most commands use the foreign architecture when
--arch option is passed.
# podman run --arch arm64 'docker.io/alpine:latest' arch
Podman 3.0.0 introduces docker-compose support. This requires enabling a Podman socket which pretends to be docker; start the
podman.service unit. For rootless containers, this requires you to start the
podman.service user unit instead and set the
$ export DOCKER_HOST="unix://$XDG_RUNTIME_DIR/podman/podman.sock"
To get hostname resolution between containers running install.
$ export DOCKER_BUILDKIT=0
unqualified-search-registriesin the defined order. The following images will always contain the prefix, to allow for configurations without
docker.ioin the configuration.
# podman pull docker.io/archlinux
See also README.md.
For a full Arch base, clone the repository from above and build your own image.
Make sure that thepackage is installed.
packages file so it only contains 'base'. Then run:
# make rootfs # podman build -t archlinux .
# podman pull docker.io/alpine
Alpine Linux uses the musl libc implementation instead of the glibc libc implementation used by most Linux distributions. Because Arch Linux uses glibc, there are a number of functional differences between an Arch Linux host and an Alpine Linux container that can impact the performance and correctness of software. A list of these differences is documented in https://wiki.musl-libc.org/functional-differences-from-glibc.html.
Note that dynamically linked software built on Arch Linux (or any other system using glibc) may have bugs and performance problems when run on Alpine Linux (or any other system using a different libc). See ,  and  for examples.
# podman pull docker.io/centos
See the Docker Hub page for a full list of available tags for each CentOS release.
# podman pull docker.io/debian
See the Docker Hub page for a full list of available tags, including both standard and slim versions for each Debian release.
Add pause to process
WARN Failed to add pause process to systemd sandbox cgroup: Process org.freedesktop.systemd1 exited with status 1
Can be solved using: https://github.com/containers/crun/issues/704
# echo +cpu +cpuset +io +memory +pids > /sys/fs/cgroup/cgroup.subtree_control
Container dns will not be enabled
WARN binary not found, container dns will not be enabled
If you installedas podman network backend you need to install
Containers terminate on shell logout
It may happen that after logging out from machine, Podman containers are stopped. To prevent that, user lingering should be enabled for user running containers:
$ loginctl enable-linger
You can also create user systemd unit as described: https://docs.podman.io/en/latest/markdown/podman-auto-update.1.html#examples
Failed to move rootless netns
$ docker-compose up
ERRO failed to move the rootless netns slirp4netns process to the systemd user.slice: Process org.freedesktop.systemd1 exited with status 1
Can be solved by starting/enabling
Error building pause image after Podman upgrade 3.x to 4.0
Error: building local pause image: finding pause binary: exec: "catatonit": executable file not found in $PATH
Install the package to fix the error.
For details on upgrading from 3.x to 4.0, see the official blog article
Error on commit in rootless mode
Error committing the finished image: error adding layer with blob "sha256:02823fca9b5444c196f1f406aa235213254af9909fca270f462e32793e2260d8": Error processing tar file(exit status 1) permitted operation
Check that the storage driver is overlay in the #Storage configuration.
Error when creating a container with bridge network in rootless mode
If you are using AppArmor you might end up with problems when creating container using a bridge network with the
dnsname plugin enabled:
$ podman network create foo
$ podman run --rm -it --network=foo docker.io/library/alpine:latest ip addr
Error: command rootless-cni-infra [alloc 89398a9315256cb1938075c377275d29c2b6ebdd75a96b5c26051a89541eb928 foo festive_hofstadter ] in container 1f4344bbd1087c892a18bacc35f4fdafbb61106c146952426488bc940a751efe failed with status 1, stdout="", stderr="exit status 3\n"
This can be solved by adding the following lines to
owner /run/user/[0-9]*/containers/cni/dnsname/*/dnsmasq.conf r, owner /run/user/[0-9]*/containers/cni/dnsname/*/addnhosts r, owner /run/user/[0-9]*/containers/cni/dnsname/*/pidfile rw,
And then reloading the AppArmor profile:
# apparmor_parser -R /etc/apparmor.d/usr.sbin.dnsmasq # apparmor_parser /etc/apparmor.d/usr.sbin.dnsmasq
No image found
By default the registry list is not populated as the files in the package come from upstream. This means that by default, trying to pull any image without specifying the registry will result in an error similar to the following:
Error: short-name "archlinux" did not resolve to an alias and no unqualified-search registries are defined in "/etc/containers/registries.conf"
A starting configuration could be the following:
unqualified-search-registries = ["docker.io"]
[[registry]] location = "docker.io"
This is equivalent to the default docker configuration.
A less convenient alternative, but having a higher compatibility with systems without configured shortnames, use the full registry path in the
Permission denied: OCI permission denied
$ podman exec openvas_openvas_1 bash
Error: crun: writing file `/email@example.com/user.slice/libpod-b3e8048a9b91e43c214b4d850ac7132155a684d6502e12e22ceb6f73848d117a.scope/container/cgroup.procs`: Permission denied: OCI permission denied
Can be solved: https://bbs.archlinux.org/viewtopic.php?id=253966
$ env DBUS_SESSION_BUS_ADDRESS= podman ... $ env DBUS_SESSION_BUS_ADDRESS= podman-compose ...
Pushing images to Docker Hub: access denied/authentication required
podman push to push container images to Docker Hub, the following errors could occur:
Requested access to the resource is denied or
Authentication required. The following hints can help to fix potential issues
- Tag the local image, e.g.,
# podman tag <localImage> docker.io/<dockerHubUsername>/<dockerHubRepository>:<Tag>
- Push the tagged image, e.g.,
# podman push docker.io/<dockerHubUsername>/<dockerHubRepository>:<Tag> docker://docker.io/<dockerHubUsername>/<dockerHubRepository>:<Tag>
- Login to docker.io, the Docker Hub repository and Docker Hub Registry server, e.g.,
# podman login -u <DockerHubUsername> -p <DockerHubPassword> registry-1.docker.io # podman login -u <DockerHubUsername> -p <DockerHubPassword> docker.io/<dockerHubUsername>/<dockerHubRepository> # podman login -u <DockerHubUsername> -p <DockerHubPassword> docker.io
- Logout from all registries before the login, e.g.,
# podman logout --all
- Add <dockerHubUsername> as collaborator in the Docker Hub Collaborators tab of the reporsitory
Buildah/Podman running as rootless expects the bind mount to be shared, check if it is set to private:
$ findmnt -o PROPAGATION / PROPAGATION private
In this case seeand set temporarily the mount as shared with:
# mount --make-shared /
To set it permanently edit /etc/fstab and add the shared option to the desired mount and reboot. It will result in a entry like:
# <device> <dir> <type> <options> <dump> <fsck> UUID=0a3407de-014b-458b-b5c1-848e92a327a3 / ext4 defaults,shared 0 1