% podman-auto-update(1)

NAME

podman-auto-update - Auto update containers according to their auto-update policy

SYNOPSIS

podman auto-update [options]

DESCRIPTION

podman auto-update looks up containers with a specified “io.containers.autoupdate” label (i.e., the auto-update policy).

If the label is present and set to “image”, Podman reaches out to the corresponding registry to check if the image has been updated. An image is considered updated if the digest in the local storage is different than the one of the remote image. If an image must be updated, Podman pulls it down and restarts the systemd unit executing the container.

If “io.containers.autoupdate.authfile” label is present, Podman reaches out to corresponding authfile when pulling images.

At container-creation time, Podman looks up the “PODMAN_SYSTEMD_UNIT” environment variables and stores it verbatim in the container’s label. This variable is now set by all systemd units generated by podman-generate-systemd and is set to %n (i.e., the name of systemd unit starting the container). This data is then being used in the auto-update sequence to instruct systemd (via DBUS) to restart the unit and hence to restart the container.

Note that podman auto-update relies on systemd and requires a fully-qualified image reference (e.g., quay.io/podman/stable:latest) to be used to create the container. This enforcement is necessary to know which image to actually check and pull. If an image ID was used, Podman would not know which image to check/pull anymore.

Moreover, the systemd units are expected to be generated with podman-generate-systemd --new, or similar units that create new containers in order to run the updated images. Systemd units that start and stop a container cannot run a new image.

Systemd Unit and Timer

Podman ships with a podman-auto-update.service systemd unit. This unit is triggered daily at midnight by the podman-auto-update.timer systemd timer. The timer can be altered for custom time-based updates if desired. The unit can further be invoked by other systemd units (e.g., via the dependency tree) or manually via systemctl start podman-auto-update.service.

OPTIONS

–authfile=path

Path of the authentication file. Default is ${XDG_RUNTIME_DIR}/containers/auth.json, which is set using podman login. If the authorization state is not found there, $HOME/.docker/config.json is checked, which is set using docker login.

Note: You can also override the default path of the authentication file by setting the REGISTRY_AUTH_FILE environment variable. export REGISTRY_AUTH_FILE=path

EXAMPLES

# Start a container
$ podman run --label "io.containers.autoupdate=image" \
    --label "io.containers.autoupdate.authfile=/some/authfile.json" \
    -d busybox:latest top
bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d

# Generate a systemd unit for this container
$ podman generate systemd --new --files bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
/home/user/containers/libpod/container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service

# Load the new systemd unit and start it
$ mv ./container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service ~/.config/systemd/user
$ systemctl --user daemon-reload

# If the previously created containers or pods are using shared resources, such as ports, make sure to remove them before starting the generated systemd units.
$ podman stop bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
$ podman rm bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d

$ systemctl --user start container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service

# Auto-update the container
$ podman auto-update
container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service

SEE ALSO

podman(1), podman-generate-systemd(1), podman-run(1), systemd.unit(5)