---
title: Configure the task scheduler
description: You specify options under heartbeat.scheduler to control the behavior of the task scheduler. Example configuration: In the example, setting limit to 10...
url: https://www.elastic.co/elastic/docs-builder/docs/3016/reference/beats/heartbeat/monitors-scheduler
products:
  - Beats
  - Heartbeat
applies_to:
  - Elastic Cloud Serverless: Generally available
  - Elastic Stack: Generally available
---

# Configure the task scheduler
You specify options under `heartbeat.scheduler` to control the behavior of the task scheduler.
Example configuration:
```yaml
heartbeat.scheduler:
  limit: 10
  location: 'UTC-08:00'
```

In the example, setting `limit` to 10 guarantees that only 10 concurrent I/O tasks will be active. An I/O task can be the actual check or resolving an address via DNS.

## `limit`

The number of concurrent I/O tasks that Heartbeat is allowed to execute. If set to 0, there is no limit. The default is 0.
Most operating systems set a file descriptor limit of 1024. For Heartbeat to operate correctly and not accidentally block libbeat output, the value that you specify for `limit` should be below the configured ulimit.

## `location`

The time zone for the scheduler. By default the scheduler uses localtime.

## `job.limit`

On top of the scheduler level limit, Heartbeat allows limiting the number of concurrent tasks per monitor/job type.
Example configuration:
```yaml
heartbeat.jobs:
  http:
    limit: 10
```

In the example, at any given time Heartbeat guarantees that only 10 concurrent `http` tasks will be active.
These limits can also be set via the environment variables `SYNTHETICS_LIMIT_{{TYPE}}`, where `{{TYPE}}` is one of `HTTP`, `TCP`, and `ICMP`.