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