The index.lifecycle.name setting in Elasticsearch is used to specify the name of the Index Lifecycle Management (ILM) policy to be applied to an index. This setting controls which lifecycle policy governs the various stages and actions an index will go through during its lifetime.
- Default value: No default value
- Possible values: Any valid ILM policy name
- Recommendations: Set this value when creating an index or updating an existing index to associate it with a specific ILM policy
The index.lifecycle.name setting is crucial for implementing automated index management strategies. By associating an index with an ILM policy, you can automate tasks such as rolling over to a new index, moving to different node types, or deleting old indices based on predefined rules.
Example
To set the ILM policy for a new index:
PUT my-index
{
"settings": {
"index.lifecycle.name": "my_policy"
}
}
In this example, we're creating a new index called my-index and associating it with an ILM policy named my_policy. This means that the index will follow the lifecycle rules defined in my_policy, which could include actions like rollover, shrink, or delete at specific points in the index's lifetime.
Changing this setting can be useful when you want to apply a different management strategy to an index, perhaps to optimize storage usage or to implement a new retention policy.
Common Issues and Misuses
- Applying a non-existent policy name
- Changing the policy on an index that has already progressed through some lifecycle phases
- Using incompatible policies for indices that are part of the same alias or data stream
Do's and Don'ts
Do's:
- Create and test ILM policies before applying them to production indices
- Use descriptive names for your ILM policies
- Regularly review and update your ILM policies as your data management needs evolve
Don'ts:
- Don't apply ILM policies to indices without understanding the implications
- Don't frequently change the ILM policy of an index, as it can lead to unexpected behavior
- Don't use the same policy for indices with vastly different purposes or retention requirements
Frequently Asked Questions
Q: Can I change the ILM policy of an existing index?
A: Yes, you can update the index.lifecycle.name setting on an existing index. However, be cautious as the new policy will take effect from the current state of the index, which may not align with the policy's phases.
Q: What happens if I delete an ILM policy that's being used by an index?
A: If you delete a policy that's in use, the indices using that policy will continue to follow the last known state of the policy. It's recommended to assign a new policy to these indices before deleting the old one.
Q: Can multiple indices use the same ILM policy?
A: Yes, multiple indices can use the same ILM policy. This is common for time-series data where you want consistent management across multiple indices.
Q: How does index.lifecycle.name interact with index templates?
A: You can specify the index.lifecycle.name in an index template. When new indices are created that match the template, they will automatically be associated with the specified ILM policy.
Q: Is it possible to disable ILM for an index after it's been enabled?
A: Yes, you can disable ILM for an index by removing the index.lifecycle.name setting. However, any actions that have already been taken by the policy will not be undone.
