open-nomad/website/source/docs/job-specification/restart.html.md
2019-05-06 14:52:44 -07:00

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---
layout: "docs"
page_title: "restart Stanza - Job Specification"
sidebar_current: "docs-job-specification-restart"
description: |-
The "restart" stanza configures a group's behavior on task failure.
---
# `restart` Stanza
<table class="table table-bordered table-striped">
<tr>
<th width="120">Placement</th>
<td>
<code>job -> group -> **restart**</code>
</td>
</tr>
</table>
The `restart` stanza configures a group's behavior on task failure. Restarts
happen on the client that is running the task.
```hcl
job "docs" {
group "example" {
restart {
attempts = 3
delay = "30s"
}
}
}
```
## `restart` Parameters
- `attempts` `(int: <varies>)` - Specifies the number of restarts allowed in the
configured interval. Defaults vary by job type, see below for more
information.
- `delay` `(string: "15s")` - Specifies the duration to wait before restarting a
task. This is specified using a label suffix like "30s" or "1h". A random
jitter of up to 25% is added to the delay.
- `interval` `(string: <varies>)` - Specifies the duration which begins when the
first task starts and ensures that only `attempts` number of restarts happens
within it. If more than `attempts` number of failures happen, behavior is
controlled by `mode`. This is specified using a label suffix like "30s" or
"1h". Defaults vary by job type, see below for more information.
- `mode` `(string: "fail")` - Controls the behavior when the task fails more
than `attempts` times in an interval. For a detailed explanation of these
values and their behavior, please see the [mode values section](#mode-values).
### `restart` Parameter Defaults
The values for many of the `restart` parameters vary by job type. Here are the
defaults by job type:
- The default batch restart policy is:
```hcl
restart {
attempts = 3
delay = "15s"
interval = "24h"
mode = "fail"
}
```
- The default service and system job restart policy is:
```hcl
restart {
interval = "30m"
attempts = 2
delay = "15s"
mode = "fail"
}
```
### `mode` Values
This section details the specific values for the "mode" parameter in the Nomad
job specification for constraints. The mode is always specified as a string
```hcl
restart {
mode = "..."
}
```
- `"delay"` - Instructs the scheduler to delay the next restart until the next
`interval` is reached.
- `"fail"` - Instructs the scheduler to not attempt to restart the task on
failure. This is the default behavior. This mode is useful for non-idempotent jobs which are unlikely to
succeed after a few failures. Failed jobs will be restarted according to
the [`reschedule`](/docs/job-specification/reschedule.html) stanza.