github.com/hanks177/podman/v4@v4.1.3-0.20220613032544-16d90015bc83/docs/source/markdown/podman-auto-update.1.md (about)

     1  % podman-auto-update(1)
     2  
     3  ## NAME
     4  podman\-auto-update - Auto update containers according to their auto-update policy
     5  
     6  ## SYNOPSIS
     7  **podman auto-update** [*options*]
     8  
     9  ## DESCRIPTION
    10  **podman auto-update** looks up containers with a specified `io.containers.autoupdate` label (i.e., the auto-update policy).
    11  
    12  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.
    13  An image is considered updated if the digest in the local storage is different than the one of the remote image.
    14  If an image must be updated, Podman pulls it down and restarts the systemd unit executing the container.
    15  
    16  The registry policy requires a fully-qualified image reference (e.g., quay.io/podman/stable:latest) to be used to create the container.
    17  This enforcement is necessary to know which image to actually check and pull.
    18  If an image ID was used, Podman would not know which image to check/pull anymore.
    19  
    20  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.
    21  If an image is updated locally, Podman simply restarts the systemd unit executing the container.
    22  
    23  If `io.containers.autoupdate.authfile` label is present, Podman reaches out to the corresponding authfile when pulling images.
    24  
    25  At container-creation time, Podman looks up the `PODMAN_SYSTEMD_UNIT` environment variable and stores it verbatim in the container's label.
    26  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).
    27  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.
    28  
    29  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.
    30  Systemd units that start and stop a container cannot run a new image.
    31  
    32  ### Systemd Unit and Timer
    33  
    34  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**.
    35  
    36  ## OPTIONS
    37  #### **--authfile**=*path*
    38  
    39  Path of the authentication file. Default is `${XDG_RUNTIME_DIR}/containers/auth.json`, which is set using **[podman login](podman-login.1.md)**.
    40  If the authorization state is not found there, `$HOME/.docker/config.json` is checked, which is set using **docker login**.
    41  
    42  Note: There is also the option to override the default path of the authentication file by setting the `REGISTRY_AUTH_FILE` environment variable. This can be done with **export REGISTRY_AUTH_FILE=_path_**.
    43  
    44  #### **--dry-run**
    45  
    46  Check for the availability of new images but do not perform any pull operation or restart any service or container.
    47  The `UPDATED` field indicates the availability of a new image with "pending".
    48  
    49  #### **--format**=*format*
    50  
    51  Change the default output format.  This can be of a supported type like 'json' or a Go template.
    52  Valid placeholders for the Go template are listed below:
    53  
    54  | **Placeholder** | **Description**                        |
    55  | --------------- | -------------------------------------- |
    56  | .Unit           | Name of the systemd unit               |
    57  | .ContainerName  | Name of the container                  |
    58  | .ContainerID    | ID of the container                    |
    59  | .Container      | ID and name of the container           |
    60  | .Image          | Name of the image                      |
    61  | .Policy         | Auto-update policy of the container    |
    62  | .Updated        | Update status: true,false,failed       |
    63  
    64  #### **--rollback**
    65  
    66  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.
    67  
    68  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.
    69  
    70  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)).
    71  
    72  
    73  ## EXAMPLES
    74  Autoupdate with registry policy
    75  
    76  ```
    77  ### Start a container
    78  $ podman run --label "io.containers.autoupdate=registry" \
    79      --label "io.containers.autoupdate.authfile=/some/authfile.json" \
    80      -d --name=test registry.fedoraproject.org/fedora:latest sleep infinity
    81  bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
    82  
    83  ### Generate a systemd unit for this container
    84  $ podman generate systemd --new --files bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
    85  /home/user/container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service
    86  
    87  ### Load the new systemd unit and start it
    88  $ mv ./container-bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d.service ~/.config/systemd/user/container-test.service
    89  $ systemctl --user daemon-reload
    90  
    91  ### 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.
    92  $ podman stop bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
    93  $ podman rm bc219740a210455fa27deacc96d50a9e20516492f1417507c13ce1533dbdcd9d
    94  
    95  $ systemctl --user start container-test.service
    96  
    97  ### Check if a newer image is available
    98  $ podman auto-update --dry-run --format "{{.Image}} {{.Updated}}"
    99  registry.fedoraproject.org/fedora:latest   pending
   100  
   101  ### Autoupdate the services
   102  $ podman auto-update
   103  UNIT                    CONTAINER            IMAGE                                     POLICY      UPDATED
   104  container-test.service  08fd34e533fd (test)  registry.fedoraproject.org/fedora:latest  registry    false
   105  ```
   106  
   107  Autoupdate with local policy
   108  
   109  ```
   110  ### Start a container
   111  $ podman run --label "io.containers.autoupdate=local" \
   112      -d busybox:latest top
   113  be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
   114  
   115  ### Generate a systemd unit for this container
   116  $ podman generate systemd --new --files be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
   117  /home/user/container-be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338.service
   118  
   119  ### Load the new systemd unit and start it
   120  $ mv ./container-be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338.service ~/.config/systemd/user
   121  $ systemctl --user daemon-reload
   122  
   123  ### 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.
   124  $ podman stop be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
   125  $ podman rm be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338
   126  
   127  $ systemctl --user start container-be0889fd06f252a2e5141b37072c6bada68563026cb2b2649f53394d87ccc338.service
   128  
   129  ### Get the name of the container
   130  $ podman ps
   131  CONTAINER ID  IMAGE                             COMMAND  CREATED        STATUS            PORTS   NAMES
   132  01f5c8113e84  docker.io/library/busybox:latest  top      2 seconds ago  Up 3 seconds ago          inspiring_galileo
   133  
   134  ### Modify the image
   135  $ podman commit --change CMD=/bin/bash inspiring_galileo busybox:latest
   136  
   137  ### Auto-update the container
   138  $ podman auto-update
   139  [...]
   140  ```
   141  
   142  ## SEE ALSO
   143  **[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)**