9d85195361
* Fix links to ACL guides * Managing Nomad guide links; links in jsx pages * job updates guide URLS * node-drain guide URLS * outage recovery guide links * fix guide links - sentinel * fix guide links - namespaces * fix guide links - quotas * fix guide links - autopilot * more guide links. * more guide links - continued. * Updating redirects for learn * Getting Started * Load Balancing Guides * update redirects for ui guide * Consolidate spark redirects to point to GH repo * operating job update part 1 * finish operating job links; operations guides links. * finish guide redirects * coalesce EOL redirects for spark guides. * one last link * Checked links and found a few more stray links * Found more .htmls * Fixup links for new HC websites * Post-merge fixups * linkcheck caught missing ids
71 lines
2.2 KiB
Plaintext
71 lines
2.2 KiB
Plaintext
---
|
|
layout: docs
|
|
page_title: lifecycle Stanza - Job Specification
|
|
sidebar_title: lifecycle
|
|
description: |-
|
|
The "lifecycle" stanza configures when a task is run within the lifecycle of a
|
|
task group
|
|
---
|
|
|
|
# `lifecycle` Stanza
|
|
|
|
<Placement groups={['job', 'group', 'task', 'lifecycle']} />
|
|
|
|
The `lifecycle` stanza is used to express task dependencies in Nomad and
|
|
configures when a task is run within the lifecycle of a task group.
|
|
|
|
Main tasks are tasks that do not have a `lifecycle` stanza. Lifecycle task hooks
|
|
are run in relation to the main tasks. Tasks can be run as Prestart Hooks, which
|
|
ensures the prestart task is run before the main tasks are run.
|
|
|
|
Tasks can be run with an additional parameter to indicate that they are
|
|
sidecars, which ensures that they are running over the duration of the whole
|
|
task group. This will allow you to run a long-lived task in a task group for a
|
|
batch job. The absence of the sidecar flag indicates that the task is ephemeral
|
|
and the task will not be restarted if it completes successfully. This allows you
|
|
to run an ephemeral prestart task in a task group for a service job, which can
|
|
serve as initialization that occurs before the main services are started.
|
|
|
|
Learn more about Nomad's task dependencies on the [HashiCorp Learn website][learn-taskdeps].
|
|
|
|
|
|
```hcl
|
|
job "docs" {
|
|
group "example" {
|
|
|
|
task "init" {
|
|
lifecycle {
|
|
hook = "prestart"
|
|
}
|
|
...
|
|
}
|
|
|
|
task "logging" {
|
|
lifecycle {
|
|
hook = "prestart"
|
|
sidecar = true
|
|
}
|
|
...
|
|
}
|
|
|
|
task "main" {
|
|
...
|
|
}
|
|
|
|
}
|
|
}
|
|
```
|
|
|
|
## `lifecycle` Parameters
|
|
|
|
- `hook` `(string: "prestart")` - Specifies when a task should be run within
|
|
the lifecycle of a group. Currently only Prestart Hooks are supported.
|
|
|
|
- `sidecar` `(bool: false)` - Controls whether or not a task is ephemeral or
|
|
long-lived within the task group. If a lifecycle task is ephemeral (`sidecar =
|
|
false`), the task will not be restarted after it completes successfully. If a
|
|
lifecycle task is long-lived (`sidecar = true`) and it terminates, it will be
|
|
restarted as long as the task group is running in its allocation.
|
|
|
|
[learn-taskdeps]: https://learn.hashicorp.com/collections/nomad/task-deps
|