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Container selection

By default, watchtower will watch all containers. However, sometimes only some containers should be updated.

There are two options:

  • Fully exclude: You can choose to exclude containers entirely from being watched by watchtower.
  • Monitor only: In this mode, watchtower checks for container updates, sends notifications and invokes the pre-check/post-check hooks on the containers but does not perform the update.

Full Exclude

If you need to exclude some containers, set the com.centurylinklabs.watchtower.enable label to false. For clarity this should be set on the container(s) you wish to be ignored, this is not set on watchtower.

LABEL com.centurylinklabs.watchtower.enable="false"

docker run -d --label=com.centurylinklabs.watchtower.enable=false someimage

version: "3"
services:
  someimage:
    container_name: someimage
    labels:
      - "com.centurylinklabs.watchtower.enable=false"

If instead you want to only include containers with the enable label, pass the --label-enable flag or the WATCHTOWER_LABEL_ENABLE environment variable on startup for watchtower and set the com.centurylinklabs.watchtower.enable label with a value of true on the containers you want to watch.

LABEL com.centurylinklabs.watchtower.enable="true"

docker run -d --label=com.centurylinklabs.watchtower.enable=true someimage

version: "3"
services:
  someimage:
    container_name: someimage
    labels:
      - "com.centurylinklabs.watchtower.enable=true"

If you wish to create a monitoring scope, you will need to run multiple instances and set a scope for each of them.

Watchtower filters running containers by testing them against each configured criteria. A container is monitored if all criteria are met. For example:

  • If a container's name is on the monitoring name list (not empty --name argument) but it is not enabled (centurylinklabs.watchtower.enable=false), it won't be monitored;
  • If a container's name is not on the monitoring name list (not empty --name argument), even if it is enabled (centurylinklabs.watchtower.enable=true and --label-enable flag is set), it won't be monitored;

Monitor Only

Individual containers can be marked to only be monitored (without being updated).

To do so, set the com.centurylinklabs.watchtower.monitor-only label to true on that container.

LABEL com.centurylinklabs.watchtower.monitor-only="true"

Or, it can be specified as part of the docker run command line:

docker run -d --label=com.centurylinklabs.watchtower.monitor-only=true someimage

When the label is specified on a container, watchtower treats that container exactly as if WATCHTOWER_MONITOR_ONLY was set, but the effect is limited to the individual container.