Docker image lifecycle policies

A Docker image lifecycle policy lets you set rules for deleting Docker images automatically.

You can configure a lifecycle policy using the Yandex Cloud CLI.

Lifecycle policy statusesLifecycle policy statuses

A lifecycle policy can have the following statuses:

• ACTIVE: The policy is active and regularly deletes Docker images according to the rules you set.
• DISABLED: The policy is disabled and doesn't delete Docker images from a repository. You can use policies in this status to create and test rules.

A repository can only have one active policy and several disabled ones. You can disable the active policy at any time.

You can perform dry runs to check which Docker images will be deleted according to the rules of the current policy.

Lifecycle policy rulesLifecycle policy rules

Prior to deletion, Docker images are first filtered by tag and then checked against lifecycle policy rules. If an image matches several rules at the same time, the rule conflict is automatically resolved.

When creating a lifecycle policy, you can place rules in a separate JSON file. Use the parameters below to configure lifecycle policy rules:

1. Filtering Docker images by tag:

   • tag_regexp: Tag to specify a filter as a regular expression.

     Usage examples for tag_regexp:

     • .*: All images with tags.
     • prefix.*: Images with tags that start with the prefix.

   • untagged: Tag to have rules applied to untagged Docker images.

2. Conditions for deleting Docker images:
   • expire_period: The period of time that must pass after creating a Docker image for it to suit the automatic deletion criteria. It must be a multiple of 24 hours.
   • retained_top: The number of Docker images (meeting the specified tag-based filter conditions) to be retained even if the expire_period already expired.

Sample JSON file with rulesSample JSON file with rules

The Test rule deletes all images that meet the following conditions:

• Tag starts with test.
• Older than 80 days.

This rule will keep 20 images.

The Untagged rule deletes all images that meet the following conditions:

• No tags.
• Older than 48 hours.

[
  {
    "description": "Test",
    "tag_regexp": "test.*",
    "expire_period": "80d",
    "retained_top": 20
  },
  {
    "description": "Untagged",
    "untagged": true,
    "expire_period": "48h"
  }
]

Where:

• description: Description of the policy rule.
• tag_regexp: Docker image tag for filtering. A test.* regular expression for tag_regexp lets you get all images with tags starting with test.
• untagged: Flag indicating that the rule applies to Docker images without tags.
• expire_period: Time after which the lifecycle policy may apply to the Docker image. This parameter is formatted as a number and a unit of measure, such as s, m, h, or d (seconds, minutes, hours, or days). expire_period must be a multiple of 24 hours.
• retained_top: Number of Docker images that are not deleted even if they match the rule.

Resolving rule conflictsResolving rule conflicts

• If a Docker image filtered by tag only falls under a single delete rule, it's deleted according to the settings of this rule.
• If a Docker image filtered by tag falls under several conflicting rules, it's deleted only if all the rules require it. If there is at least one rule saying that a Docker image shouldn't be deleted, the image is retained.