mirror of https://github.com/containers/podman.git
152 lines
8.5 KiB
Markdown
152 lines
8.5 KiB
Markdown
% podman-auto-update 1
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## NAME
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podman\-auto-update - Auto update containers according to their auto-update policy
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## SYNOPSIS
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**podman auto-update** [*options*]
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## DESCRIPTION
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**podman auto-update** looks up containers with a specified `io.containers.autoupdate` label (i.e., the auto-update policy).
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If the label is present and set to `registry`, Podman reaches out to the corresponding registry to check if the image has been updated. The label `image` is an alternative to `registry` maintained for backwards compatibility.
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An image is considered updated if the digest in the local storage is different than the one of the remote image.
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If an image must be updated, Podman pulls it down and restarts the systemd unit executing the container.
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The registry policy requires a fully-qualified image reference (e.g., quay.io/podman/stable:latest) to be used to create the container.
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This enforcement is necessary to know which image to actually check and pull.
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If an image ID was used, Podman would not know which image to check/pull anymore.
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Alternatively, if the autoupdate label is set to `local`, Podman will compare the image a container is using to the image with its raw name in local storage.
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If an image is updated locally, Podman simply restarts the systemd unit executing the container.
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If `io.containers.autoupdate.authfile` label is present, Podman reaches out to the corresponding authfile when pulling images.
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At container-creation time, Podman looks up the `PODMAN_SYSTEMD_UNIT` environment variable and stores it verbatim in the container's label.
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This variable is now set by all systemd units generated by **[podman-generate-systemd](podman-generate-systemd.1.md)** and is set to `%n` (i.e., the name of systemd unit starting the container).
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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.
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Note that **podman auto-update** relies on systemd. The systemd units are expected to be generated with **[podman-generate-systemd --new](podman-generate-systemd.1.md#--new)**, or similar units that create new containers in order to run the updated images.
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Systemd units that start and stop a container cannot run a new image.
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### Auto Updates and Kubernetes YAML
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Podman supports auto updates for Kubernetes workloads. As mentioned above, `podman auto-update` requires the containers to be running systemd. Podman ships with a systemd template that can be instantiated with a Kubernetes YAML file, see podman-generate-systemd(1).
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To enable auto updates for containers running in a Kubernetes workload, set the following Podman-specific annotations in the YAML:
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* `io.containers.autoupdate: "registry|local"` to apply the auto-update policy to all containers
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* `io.containers.autoupdate/$container: "registry|local"` to apply the auto-update policy to `$container` only
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* `io.containers.sdnotify: "conmon|container"` to apply the sdnotify policy to all containers
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* `io.containers.sdnotify/$container: "conmon|container"` to apply the sdnotify policy to `$container` only
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By default, the autoupdate policy is set to "disabled", the sdnotify policy is set to "conmon".
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### Systemd Unit and Timer
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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**.
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## OPTIONS
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@@option authfile
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#### **--dry-run**
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Check for the availability of new images but do not perform any pull operation or restart any service or container.
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The `UPDATED` field indicates the availability of a new image with "pending".
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#### **--format**=*format*
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Change the default output format. This can be of a supported type like 'json' or a Go template.
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Valid placeholders for the Go template are listed below:
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| **Placeholder** | **Description** |
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| --------------- | -------------------------------------- |
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| .Unit | Name of the systemd unit |
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| .ContainerName | Name of the container |
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| .ContainerID | ID of the container |
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| .Container | ID and name of the container |
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| .Image | Name of the image |
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| .Policy | Auto-update policy of the container |
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| .Updated | Update status: true,false,failed |
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#### **--rollback**
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If restarting a systemd unit after updating the image has failed, rollback to using the previous image and restart the unit another time. Default is true.
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Please note that detecting if a systemd unit has failed is best done by the container sending the READY message via SDNOTIFY. This way, restarting the unit will wait until having received the message or a timeout kicked in. Without that, restarting the systemd unit may succeed even if the container has failed shortly after.
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For a container to send the READY message via SDNOTIFY it must be created with the `--sdnotify=container` option (see podman-run(1)). The application running inside the container can then execute `systemd-notify --ready` when ready or use the sdnotify bindings of the specific programming language (e.g., sd_notify(3)).
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## EXAMPLES
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Autoupdate with registry policy
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```
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### Start a container
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$ podman run --label "io.containers.autoupdate=registry" \
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--label "io.containers.autoupdate.authfile=/some/authfile.json" \
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-d --name=test registry.fedoraproject.org/fedora:latest sleep infinity
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bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
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### Generate a systemd unit for this container
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$ podman generate systemd --new --files bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
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/home/user/container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service
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### Load the new systemd unit and start it
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$ mv ./container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service ~/.config/systemd/user/container-test.service
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$ systemctl --user daemon-reload
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### 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.
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$ podman stop bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
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$ podman rm bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
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$ systemctl --user start container-test.service
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### Check if a newer image is available
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$ podman auto-update --dry-run --format "{{.Image}} {{.Updated}}"
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registry.fedoraproject.org/fedora:latest pending
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### Autoupdate the services
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$ podman auto-update
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UNIT CONTAINER IMAGE POLICY UPDATED
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container-test.service 08fd34e533fd (test) registry.fedoraproject.org/fedora:latest registry false
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```
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Autoupdate with local policy
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```
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### Start a container
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$ podman run --label "io.containers.autoupdate=local" \
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-d busybox:latest top
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be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
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### Generate a systemd unit for this container
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$ podman generate systemd --new --files be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
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/home/user/container-be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338.service
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### Load the new systemd unit and start it
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$ mv ./container-be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338.service ~/.config/systemd/user
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$ systemctl --user daemon-reload
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### 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.
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$ podman stop be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
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$ podman rm be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
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$ systemctl --user start container-be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338.service
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### Get the name of the container
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$ podman ps
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CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
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01f5c8113e84 docker.io/library/busybox:latest top 2 seconds ago Up 3 seconds ago inspiring_galileo
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### Modify the image
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$ podman commit --change CMD=/bin/bash inspiring_galileo busybox:latest
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### Auto-update the container
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$ podman auto-update
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[...]
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```
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## SEE ALSO
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**[podman(1)](podman.1.md)**, **[podman-generate-systemd(1)](podman-generate-systemd.1.md)**, **[podman-run(1)](podman-run.1.md)**, **sd_notify(3)**, **[systemd.unit(5)](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)**
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