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 Set capacity limits in the Max Parallel Tests tab of the Settings dialog in Device Management. The tab lists every host machine in the organization, so you can set limits for one machine, several machines, or all machines in one save. Sign in to Kobiton Portal using an account with the ADMIN predefined role. Select your profile picture, then choose Settings. Open Device Management. Select Settings at the top of Device Management. Select the Max Parallel Tests tab. Organizations without virtualUSB see only this tab. To find a host machine, enter its name or IP address in the search field. Set the limit for each host machine: Unlimited (default): no limit for the host machine. Custom limit: enter a limit between 1 and 999 in the field that appears. The recommended value is 26. To apply one limit to every host machine, use the All machines row at the top of the list: Select Unlimited to remove the limit from every host machine. Select Custom limit, then enter a value to apply it to every host machine. When host machines have different limits, the All machines row shows Mixed. If you change an individual host machine after setting All machines, the row returns to Mixed. Select Save. Save is blocked until every Custom limit has a value. A message appears next to each missing value. Save applies all changes made in the Settings dialog. If the save fails, an error message appears, the dialog stays open, and your changes are kept so you can try again. To close the dialog without saving, select Cancel or the close icon, then confirm You have unsaved changes. Leave anyway? A machine that is offline when you save is not updated. The dialog stays open and reports which machines were rejected. 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. When visible, the Launch button is disabled. In the Device Details, both the Launch and Retain buttons are disabled. Starting a session through Kobiton Portal, the API, automation, or virtualUSB while the host is at capacity returns the following error: Host has reached its configured capacity. Please try again later. In virtualUSB, the Connect button remains enabled for devices on a host at capacity. Selecting Connect returns the error above in both the virtualUSB desktop app and the virtualUSB CLI. Connect again after a session on the host ends. Capacity limits apply only to new sessions. Existing sessions are not interrupted if a lower limit is set after they have started. Recommended actions when capacity is reached 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.