Control the capacity of a host machine

Overview

Configure and manage the maximum number of parallel test sessions that can run on a host machine. This setting acts as a governor to control overall test execution capacity.

This guide goes over:

  • What a host machine capacity limit is and when it should be set

  • How to configure the capacity limit

  • How device availability changes when the limit is reached

  • Recommended actions when capacity is exceeded

Host machine capacity limits

Each host machine has a finite capacity for running parallel test sessions. Capacity is determined by hardware resources and runtime conditions, and may be lower than the total number of devices connected to the host.

If a host machine meets Kobiton’s hardware requirements, it can typically support up to 26 parallel sessions.

For this reason, capacity limits are generally required only when more than 26 devices are connected to a single host.

Set the Max Parallel Tests

To configure a capacity limit for a host machine:

  1. Sign in to the Kobiton Portal using an account with the ADMIN predefined role.

  2. Select your profile picture, then choose Settings.

  3. Open Device Management.

  4. Select Settings for the target host machine.

    The Settings option of a host machine in Device Management

  5. In the pop-up, choose one of the following options:

    • Unlimited (default): no limit for the host machine.

    • Set custom limit: set a limit between 1 and 999.

      The recommended value is 26.

      The available options for setting capacity limit of a host machine

  6. Select Save.

How the capacity limit affects sessions

Once a capacity limit is set, the total number of parallel sessions on the host is restricted to the configured value.

The following session types count toward the capacity limit:

  • Scriptless (Revisit)

  • Manual

  • Appium Automation

  • Native Espresso/UiAutomator Automation

  • Native XCUITest Automation

  • Gaming (Turbo Test GameDriver)

  • Turbo Test Appium

  • Mixed

  • CLI

  • API

  • Clean-up

  • Retained

When the capacity limit is reached, devices hosted on the machine remain online but are not immediately available for launch. By default, these devices are hidden in the Devices list.

To view them, clear the Hide unavailable devices filter.

The Hide unavailable devices option in the Devices list filter

When visible, the Launch button is disabled.

An available device with the Launch button disabled

In the Device Details, both the Launch and Retain buttons are disabled.

The disabled Launch and Retain button in Device Details

If a session is initiated through the Portal, API, or automation while the host is at capacity, the following error is returned:

Host has reached its configured capacity. Please try again later.

Capacity limits apply only to new sessions.

Existing sessions are not interrupted if a lower limit is set after they have started.

If a host machine reaches its capacity limit:

  • Wait for active sessions to complete before launching new ones.

  • Launch a similar device hosted on a different machine with available capacity.

  • Release retained devices when possible to free capacity for additional sessions.