--- layout: "docs" page_title: "migrate Stanza - Job Specification" sidebar_current: "docs-job-specification-migrate" description: |- The "migrate" stanza specifies the group's migrate strategy. The migrate strategy is used to control the job's behavior when it is being migrated off of a draining node. --- # `migrate` Stanza
Placement job -> **migrate**
job -> group -> **migrate**
The `migrate` stanza specifies the group's strategy for migrating off of [draining][drain] nodes. If omitted, a default migration strategy is applied. If specified at the job level, the configuration will apply to all groups within the job. Only service jobs with a count greater than 1 support migrate stanzas. ```hcl job "docs" { migrate { max_parallel = 1 health_check = "checks" min_healthy_time = "10s" healthy_deadline = "5m" } } ``` When one or more nodes are draining, only `max_parallel` allocations will be stopped at a time. Node draining will not continue until replacement allocations have been healthy for their `min_healthy_time` or `healthy_deadline` is reached. Note that a node's drain [deadline][deadline] will override the `migrate` stanza for allocations on that node. The `migrate` stanza is for job authors to define how their services should be migrated, while the node drain deadline is for system operators to put hard limits on how long a drain may take. See the [Decommissioning Nodes guide](/guides/node-draining.html) for details on node draining. ## `migrate` Parameters - `max_parallel` `(int: 1)` - Specifies the number of allocations that can be migrated at the same time. This number must be less than the total [`count`][count] for the group as `count - max_parallel` will be left running during migrations. - `health_check` `(string: "checks")` - Specifies the mechanism in which allocations health is determined. The potential values are: - "checks" - Specifies that the allocation should be considered healthy when all of its tasks are running and their associated [checks][checks] are healthy, and unhealthy if any of the tasks fail or not all checks become healthy. This is a superset of "task_states" mode. - "task_states" - Specifies that the allocation should be considered healthy when all its tasks are running and unhealthy if tasks fail. - `min_healthy_time` `(string: "10s")` - Specifies the minimum time the allocation must be in the healthy state before it is marked as healthy and unblocks further allocations from being migrated. This is specified using a label suffix like "30s" or "15m". - `healthy_deadline` `(string: "5m")` - Specifies the deadline in which the allocation must be marked as healthy after which the allocation is automatically transitioned to unhealthy. This is specified using a label suffix like "2m" or "1h". [checks]: /docs/job-specification/service.html#check-parameters [count]: /docs/job-specification/group.html#count [drain]: /docs/commands/node/drain.html [deadline]: /docs/commands/node/drain.html#deadline