Lifecycle Policies

What is a Lifecycle Policy?

A lifecycle policy is a set of rules automating the management of objects within a specific bucket. It can help with storage efficiency or to ensure compliance. For example, a policy may be created to automatically delete objects based on criteria such as object name, age, size, creation date, etc.

Only one lifecycle policy can be configured on a bucket, but one lifecycle policy can contain multiple rules. A Lifecycle policy is independent of a bucket policy.

Lifecycle rules are executed asynchronously and typically run once per day. The exact timing is not user-configurable. It may take up to 24 hours for a rule to be applied to an object, depending on factors like object creation time and the rule's conditions.

Key Components of a Lifecycle Policy

• ID: A unique identifier for the lifecycle rule, used for tracking and management.
• Filter: Specifies which objects the rule applies to, based on prefixes or tags.
  • Example: Use a Prefix to target objects in a specific 'folder'.
• Status: Indicates whether the rule is Enabled or Disabled.
• Expiration: Defines when objects are automatically deleted. This can be specified in:
  • Days: Number of days from object creation.
  • Date: A specific date when the rule applies.

Example Lifecycle Policies

This policy automatically:

• deletes all objects that are older than 60 days.
• deletes objects under the logs/ prefix that are older than 30 days.
• deletes all objects in the bucket on 2024-12-31.

{
  "Rules": [
    {
      "ID": "DeleteOldObjects",
      "Filter": {
        "Prefix": ""
      },
      "Status": "Enabled",
      "Expiration": {
        "Days": 60
      }
    },
    {
      "ID": "DeleteOldLogs",
      "Filter": {
        "Prefix": "logs/"
      },
      "Status": "Enabled",
      "Expiration": {
        "Days": 30
      }
    },
    {
      "ID": "DeleteByDate",
      "Filter": {
        "Prefix": ""
      },
      "Status": "Enabled",
      "Expiration": {
        "Date": "2024-12-31T00:00:00.000Z"
      }
    }
  ]
}

This policy ensures that non-current versions of objects are automatically deleted after they have been non-current for 90 days. The rule has no effect if versioning is disabled on the bucket.

{
    "Rules": [
        {
            "ID": "ExpireOldVersions",
            "Status": "Enabled",
            "Filter": {
                "Prefix": ""
            },
            "NoncurrentVersionExpiration": {
                "NoncurrentDays": 90
            }
        }
    ]
}

Manage Lifecycle Policies

To apply a lifecycle policy use the following command (no output if successful):

aws s3api put-bucket-lifecycle-configuration --bucket <bucket-name> --lifecycle-configuration file://lifecycle-policy.json

To check the lifecycle policy currently applied to an S3 bucket, use the following command:

aws s3api get-bucket-lifecycle-configuration --bucket <bucket-name>

If no lifecycle policy applied to the bucket you should get:

NoSuchLifecycleConfiguration

However, in some cases you might get:

argument of type 'NoneType' is not iterable

This is a known issue and does not impact the fact that no lifecycle policy exists on the bucket.

To remove a bucket policy, use the following command (no output if successful):

aws s3api delete-bucket-lifecycle --bucket <bucket-name>

Best Practices for Lifecycle Policies

• Scope Policies Using Filters: Apply rules to specific 'folders' using prefixes.

• Manage Non-Current Versions: When versioning is enabled, set rules to expire non-current object versions after a defined period to reduce storage costs.

• Test Policies Before Deployment: Apply lifecycle rules to a non-critical test bucket first to validate their behavior. Confirm that objects are managed as expected before using the rules in production.

• Use Descriptive Rule IDs: Assign meaningful ID values to lifecycle rules for easy identification and management, especially in buckets with multiple rules.

• Avoid Unintended Deletions: Double-check lifecycle rules to ensure critical data is not inadvertently deleted. Limit rules to specific prefixes or tagged objects to reduce risks.

• Keep Policies Updated: Periodically review lifecycle policies to ensure they reflect current storage and business needs. Remove outdated or unused rules to maintain clarity.