111 lines
4.3 KiB
Plaintext
111 lines
4.3 KiB
Plaintext
[role="xpack"]
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[testenv="basic"]
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[[ilm-index-lifecycle]]
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=== Index lifecycle
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++++
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<titleabbrev>Index lifecycle</titleabbrev>
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++++
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{ilm-init} defines five index lifecycle _phases_:
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* **Hot**: The index is actively being updated and queried.
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* **Warm**: The index is no longer being updated but is still being queried.
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* **Cold**: The index is no longer being updated and is seldom queried. The
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information still needs to be searchable, but it's okay if those queries are
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slower.
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* **Frozen**: The index is no longer being updated and is seldom queried. The
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queries are performing longer-term analyses for which a slower response is
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acceptable.
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* **Delete**: The index is no longer needed and can safely be removed.
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An index's _lifecycle policy_ specifies which phases
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are applicable, what actions are performed in each phase,
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and when it transitions between phases.
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You can manually apply a lifecycle policy when you create an index.
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For time series indices, you need to associate the lifecycle policy with
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the index template used to create new indices in the series.
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When an index rolls over, a manually-applied policy isn't automatically applied to the new index.
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[discrete]
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[[ilm-phase-transitions]]
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=== Phase transitions
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{ilm-init} moves indices through the lifecycle according to their age.
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To control the timing of these transitions, you set a _minimum age_ for each phase.
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For an index to move to the next phase, all actions in the current phase must be complete and
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the index must be older than the minimum age of the next phase.
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The minimum age defaults to zero, which causes {ilm-init} to move indices to the next phase
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as soon as all actions in the current phase complete.
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If an index has unallocated shards and the <<cluster-health,cluster health status>> is yellow,
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the index can still transition to the next phase according to its {ilm} policy.
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However, because {es} can only perform certain clean up tasks on a green
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cluster, there might be unexpected side effects.
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To avoid increased disk usage and reliability issues,
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address any cluster health problems in a timely fashion.
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[discrete]
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[[ilm-phase-execution]]
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=== Phase execution
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{ilm-init} controls the order in which the actions in a phase are executed and
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what _steps_ are executed to perform the necessary index operations for each action.
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When an index enters a phase, {ilm-init} caches the phase definition in the index metadata.
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This ensures that policy updates don't put the index into a state where it can never exit the phase.
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If changes can be safely applied, {ilm-init} updates the cached phase definition.
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If they cannot, phase execution continues using the cached definition.
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{ilm-init} runs periodically, checks to see if an index meets policy criteria,
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and executes whatever steps are needed.
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To avoid race conditions, {ilm-init} might need to run more than once to execute all of the steps
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required to complete an action.
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For example, if {ilm-init} determines that an index has met the rollover criteria,
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it begins executing the steps required to complete the rollover action.
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If it reaches a point where it is not safe to advance to the next step, execution stops.
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The next time {ilm-init} runs, {ilm-init} picks up execution where it left off.
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This means that even if `indices.lifecycle.poll_interval` is set to 10 minutes and an index meets
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the rollover criteria, it could be 20 minutes before the rollover is complete.
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[discrete]
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[[ilm-phase-actions]]
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=== Phase actions
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{ilm-init} supports the following actions in each phase.
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* Hot
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- <<ilm-set-priority,Set Priority>>
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- <<ilm-unfollow,Unfollow>>
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- <<ilm-rollover,Rollover>>
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* Warm
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- <<ilm-set-priority,Set Priority>>
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- <<ilm-unfollow,Unfollow>>
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- <<ilm-readonly,Read-Only>>
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- <<ilm-allocate,Allocate>>
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- <<ilm-shrink,Shrink>>
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- <<ilm-forcemerge,Force Merge>>
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* Cold
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- <<ilm-set-priority-action,Set Priority>>
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- <<ilm-unfollow-action,Unfollow>>
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- <<ilm-allocate,Allocate>>
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- <<ilm-freeze,Freeze>>
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ifdef::permanently-unreleased-branch[]
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- <<ilm-searchable-snapshot, Searchable Snapshot>>
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endif::[]
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* Frozen
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- <<ilm-set-priority-action,Set Priority>>
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- <<ilm-unfollow-action,Unfollow>>
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- <<ilm-allocate,Allocate>>
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- <<ilm-freeze,Freeze>>
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ifdef::permanently-unreleased-branch[]
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- <<ilm-searchable-snapshot, Searchable Snapshot>>
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endif::[]
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* Delete
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- <<ilm-wait-for-snapshot-action,Wait For Snapshot>>
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- <<ilm-delete,Delete>>
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