podman-generate-systemd(1)

NAME

podman-generate-systemd - Generate systemd unit file(s) for a container or pod. Not supported for the remote client

SYNOPSIS

podman generate systemd [options] container|pod

DESCRIPTION

podman generate systemd will create a systemd unit file that can be used to control a container or pod. By default, the command will print the content of the unit files to stdout.

Note: If you use this command with the remote client, you would still have to place the generated units on the remote system.

OPTIONS:

--files, -f

Generate files instead of printing to stdout. The generated files are named {container,pod}-{ID,name}.service and will be placed in the current working directory.

Note: On a system with SELinux enabled, the generated files will inherit contexts from the current working directory. Depending on the SELinux setup, changes to the generated files using restorecon, chcon, or semanage may be required to allow systemd to access these files. Alternatively, use the -Z option when running mv or cp.

--format=format

Print the created units in specified format (json). If --files is specified the paths to the created files will be printed instead of the unit content.

--name, -n

Use the name of the container for the start, stop, and description in the unit file

--new

Using this flag will yield unit files that do not expect containers and pods to exist. Instead, new containers and pods are created based on their configuration files. The unit files are created best effort and may need to be further edited; please review the generated files carefully before using them in production.

--time, -t=value

Override the default stop timeout for the container with the given value.

--restart-policy=policy

Set the systemd restart policy. The restart-policy must be one of: "no", "on-success", "on-failure", "on-abnormal", "on-watchdog", "on-abort", or "always". The default policy is on-failure.

--container-prefix=prefix

Set the systemd unit name prefix for containers. The default is container.

--pod-prefix=prefix

Set the systemd unit name prefix for pods. The default is pod.

--separator=separator

Set the systemd unit name separator between the name/id of a container/pod and the prefix. The default is -.

Examples

  Generate and print a systemd unit file for a container

Generate a systemd unit file for a container running nginx with an always restart policy and 1-second timeout to stdout.

    $ podman create --name nginx nginx:latest
    $ podman generate systemd --restart-policy=always -t 1 nginx
    # container-de1e3223b1b888bc02d0962dd6cb5855eb00734061013ffdd3479d225abacdc6.service
    # autogenerated by Podman 1.8.0
    # Wed Mar 09 09:46:45 CEST 2020
    [Unit]
    Description=Podman container-de1e3223b1b888bc02d0962dd6cb5855eb00734061013ffdd3479d225abacdc6.service
    Documentation=man:podman-generate-systemd(1)
    [Service]
    Restart=always
    ExecStart=/usr/bin/podman start de1e3223b1b888bc02d0962dd6cb5855eb00734061013ffdd3479d225abacdc6
    ExecStop=/usr/bin/podman stop -t 1 de1e3223b1b888bc02d0962dd6cb5855eb00734061013ffdd3479d225abacdc6
    KillMode=none
    Type=forking
    PIDFile=/run/user/1000/overlay-containers/de1e3223b1b888bc02d0962dd6cb5855eb00734061013ffdd3479d225abacdc6/userdata/conmon.pid
    [Install]
    WantedBy=multi-user.target default.target

  Generate systemd unit file for a container with --new flag

The --new flag generates systemd unit files that create and remove containers at service start and stop commands (see ExecStartPre and ExecStopPost service actions). Such unit files are not tied to a single machine and can easily be shared and used on other machines.

    $ sudo podman generate systemd --new --files --name bb310a0780ae
    # container-busy_moser.service
    # autogenerated by Podman 1.8.3
    # Fri Apr  3 09:40:47 EDT 2020
    [Unit]
    Description=Podman container-busy_moser.service
    Documentation=man:podman-generate-systemd(1)
    Wants=network.target
    After=network-online.target
    [Service]
    Environment=PODMAN_SYSTEMD_UNIT=%n
    Restart=on-failure
    ExecStartPre=/bin/rm -f %t/%n-pid %t/%n-cid
    ExecStart=/usr/local/bin/podman run --conmon-pidfile %t/%n-pid --cidfile %t/%n-cid --cgroups=no-conmon -d -dit alpine
    ExecStop=/usr/local/bin/podman stop --ignore --cidfile %t/%n-cid -t 10
    ExecStopPost=/usr/local/bin/podman rm --ignore -f --cidfile %t/%n-cid
    PIDFile=%t/%n-pid
    KillMode=none
    Type=forking
    [Install]
    WantedBy=multi-user.target default.target

  Generate systemd unit files for a pod with two simple alpine containers

Note systemctl should only be used on the pod unit and one should not start or stop containers individually via systemctl, as they are managed by the pod service along with the internal infra-container.

You can still use systemctl status or journalctl to examine container or pod unit files.

    $ podman pod create --name systemd-pod
    $ podman create --pod systemd-pod alpine top
    $ podman create --pod systemd-pod alpine top
    $ podman generate systemd --files --name systemd-pod
    /home/user/pod-systemd-pod.service
    /home/user/container-amazing_chandrasekhar.service
    /home/user/container-jolly_shtern.service
    $ cat pod-systemd-pod.service
    # pod-systemd-pod.service
    # autogenerated by Podman 1.8.0
    # Wed Mar 09 09:52:37 CEST 2020
    [Unit]
    Description=Podman pod-systemd-pod.service
    Documentation=man:podman-generate-systemd(1)
    Requires=container-amazing_chandrasekhar.service container-jolly_shtern.service
    Before=container-amazing_chandrasekhar.service container-jolly_shtern.service
    [Service]
    Restart=on-failure
    ExecStart=/usr/bin/podman start 77a818221650-infra
    ExecStop=/usr/bin/podman stop -t 10 77a818221650-infra
    KillMode=none
    Type=forking
    PIDFile=/run/user/1000/overlay-containers/ccfd5c71a088768774ca7bd05888d55cc287698dde06f475c8b02f696a25adcd/userdata/conmon.pid
    [Install]
    WantedBy=multi-user.target default.target

  Installation of generated systemd unit files.

Podman-generated unit files include an [Install] section, which carries installation information for the unit. It is used by the enable and disable commands of systemctl(1) during installation.

Once you have generated the systemd unit file, you can copy the generated systemd file to /etc/systemd/system for installing as a root user and to $HOME/.config/systemd/user for installing it as a non-root user. Enable the copied unit file or files using systemctl enable.

Note: Coping unit files to /etc/systemd/system and enabling it marks the unit file to be automatically started at boot. And smillarly, coping a unit file to $HOME/.config/systemd/user and enabling it marks the unit file to be automatically started on user login.

    # Generated systemd files.
    $ podman pod create --name systemd-pod
    $ podman create --pod systemd-pod alpine top
    $ podman generate systemd --files --name systemd-pod
    # Copy all the generated files.
    $ sudo cp pod-systemd-pod.service container-great_payne.service /etc/systemd/system
    $ systemctl enable pod-systemd-pod.service
    Created symlink /etc/systemd/system/multi-user.target.wants/pod-systemd-pod.service → /etc/systemd/system/pod-systemd-pod.service.
    Created symlink /etc/systemd/system/default.target.wants/pod-systemd-pod.service → /etc/systemd/system/pod-systemd-pod.service.
    $ systemctl is-enabled pod-systemd-pod.service
    enabled

To run the user services placed in $HOME/.config/systemd/user on first login of that user, enable the service with --user flag.

    $ systemctl --user enable <.service>

The systemd user instance is killed after the last session for the user is closed. The systemd user instance can be kept running ever after the user logs out by enabling lingering using

    $ loginctl enable-linger <username>

  Use systemctl to perform operations on generated installed unit files.

Create and enable systemd unit files for a pod using the above examples as reference and use systemctl to perform operations.

Since systemctl defaults to using the root user, all the changes using the systemctl can be seen by appending sudo to the podman cli commands. To perform systemctl actions as a non-root user use the --user flag when interacting with systemctl.

    $ systemctl --user start pod-systemd-pod.service
    $ podman pod ps
    POD ID         NAME          STATUS    CREATED          # OF CONTAINERS   INFRA ID
    0815c7b8e7f5   systemd-pod   Running   29 minutes ago   2                 6c5d116f4bbe
    $ sudo podman ps # 0 Number of pods on root.
    CONTAINER ID  IMAGE  COMMAND  CREATED  STATUS  PORTS  NAMES
    $ systemctl stop pod-systemd-pod.service
    $ podman pod ps
    POD ID         NAME          STATUS   CREATED          # OF CONTAINERS   INFRA ID
    272d2813c798   systemd-pod   Exited   29 minutes ago   2                 6c5d116f4bbe

Create a simple alpine container and generate the systemd unit file with --new flag. Enable the service and control operations using the systemctl commands.

Note: When starting the container using systemctl start rather than altering the already running container it spins up a "new" container with similar configuration.

    # Enable the service.
    $ sudo podman ps -a
    CONTAINER ID  IMAGE                            COMMAND  CREATED        STATUS     PORTS  NAMES
    bb310a0780ae  docker.io/library/alpine:latest  /bin/sh  2 minutes ago  Created           busy_moser
    $ sudo systemctl start container-busy_moser.service
    $ sudo podman ps -a
    CONTAINER ID  IMAGE                            COMMAND  CREATED        STATUS            PORTS      NAMES
    772df2f8cf3b  docker.io/library/alpine:latest  /bin/sh  1 second ago   Up 1 second ago              distracted_albattani
    bb310a0780ae  docker.io/library/alpine:latest  /bin/sh  3 minutes ago  Created                      busy_moser

SEE ALSO

podman(1), systemctl(1), systemd.unit(5), systemd.service(5)

HISTORY

April 2020, Updated details and added usecase to use generated .service files as root and non-root, by Sujil Shah (sushah at redhat dot com)

August 2019, Updated with pod support by Valentin Rothberg (rothberg at redhat dot com)

April 2019, Originally compiled by Brent Baude (bbaude at redhat dot com)