Migrate
editMigrate
editPhases allowed: warm, cold.
Moves the index to the data tier that corresponds
to the current phase by updating the index.routing.allocation.include._tier_preference
index setting.
ILM automatically injects the migrate action in the warm and cold
phases if no allocation options are specified with the allocate action.
If you specify an allocate action that only modifies the number of index
replicas, ILM reduces the number of replicas before migrating the index.
To prevent automatic migration without specifying allocation options,
you can explicitly include the migrate action and set the enabled option to false.
In the warm phase, the migrate action sets index.routing.allocation.include._tier_preference
to data_warm,data_hot. This moves the index to nodes in the
warm tier. If there are no nodes in the warm tier, it falls back to the
hot tier.
In the cold phase, the migrate action sets
index.routing.allocation.include._tier_preference
to data_cold,data_warm,data_hot. This moves the index to nodes in the
cold tier. If there are no nodes in the cold tier, it falls back to the
warm tier, or the hot tier if there are no warm nodes available.
The migrate action is not allowed in the hot phase. The initial index allocation is performed automatically, and can be configured manually or via index templates.
Options
edit-
enabled -
(Optional, Boolean)
Controls whether ILM automatically migrates the index during this phase.
Defaults to
true.
Example
editIn the following policy, the allocate action is specified to reduce the number of replicas before ILM migrates the index to warm nodes.
Explicitly specifying the migrate action is not required—ILM automatically performs the migrate action unless you specify allocation options or disable migration.
PUT _ilm/policy/my_policy
{
"policy": {
"phases": {
"warm": {
"actions": {
"migrate" : {
},
"allocate": {
"number_of_replicas": 1
}
}
}
}
}
}
Disable automatic migration
editThe migrate action in the following policy is disabled and
the allocate action assigns the index to nodes that have a
rack_id of one or two.
Explicitly disabling the migrate action is not required—ILM does not inject the migrate action if you specify allocation options.
PUT _ilm/policy/my_policy
{
"policy": {
"phases": {
"warm": {
"actions": {
"migrate" : {
"enabled": false
},
"allocate": {
"include" : {
"rack_id": "one,two"
}
}
}
}
}
}
}