---
layout: docs
page_title: schedule block in the job specification
description: |-
  Time based task execution is enabled by using the `schedule` task block.
---

# `schedule` block in the job specification

<Placement groups={['job', 'group', 'task', 'periodic']} />

Time based task execution is enabled by using the `schedule` block. The
`schedule` block controls when a task is allowed to be running.

<EnterpriseAlert product="nomad"/>

~> **Note:** Time based task execution is an experimental feature and subject
to change. This feature is supported for select customers. Please refer to the
[Upgrade Guide][upgrade] to find breaking changes.

Unlike [`periodic`][periodic] jobs, the `schedule` block applies to individual
tasks. The Nomad Client starts and stops tasks at the specified time without
interaction with the Nomad Servers. This means time based task execution works
even when a Client is disconnected from Servers. The task's resources remain
allocated even outside the `schedule` when the task itself is stopped.

```hcl
job "docs" {
  group "tbte" {
    task "scheduled" {
      schedule {
        cron {
          start    = "30 9 * * MON-FRI *"
          end      = "0 16"
          timezone = "America/New_York"
        }
      }
    }
  }
}
```

## Parameters

The `schedule` block must have a `cron` block containing:

- `start` `(string: <required>)` - When the task should be started. Specified in 6 field
  [cron format][cron] (no seconds) without `,` or `/` characters.

- `end` `(string: <required>)` - When the task should be stopped
  ([`kill_signal`][kill_signal] and [`kill_timeout`][kill_timeout] apply).
  Specified in 2 field [cron format][cron] (minute and hour) without `,` or `/`
  characters.

- `timezone` `(string: "Local")` - What time zone the `start` and `end` times
  are specified in. Defaults to the local time zone of the Nomad Client the job
  is scheduled onto.

## Limitations

- Job deployments outside of the specified `schedule` will be unable to
  succeed. To update a job using time based task execution outside of its
  schedule, do a [force
  update](/nomad/docs/job-specification/update#max_parallel-0).

- Overnight schedules are currently not supported. Adjusting the `timezone`
  should allow converting overnight schedules to times within a single day.

[periodic]: /nomad/docs/job-specification/periodic
[kill_signal]: /nomad/docs/job-specification/task#kill_signal
[kill_timeout]: /nomad/docs/job-specification/task#kill_timeout
[cron]: https://github.com/hashicorp/cronexpr#implementation 'List of cron expressions'
[upgrade]: /nomad/docs/upgrade/upgrade-specific
