Zero downtime upgrades let you upgrade Unified Access Gateway with no downtime for the users. Before you upgrade a Unified Access Gateway appliance, the quiesce mode in the Unified Access Gateway system configuration pages is changed from NO to YES.

When the quiesce mode value is YES, the Unified Access Gateway appliance is shown as not available when the load balancer checks the health of the appliance. Requests that come to the load balancer are sent to the next Unified Access Gateway appliance that is behind the load balancer.


  • Two or more Unified Access Gateway appliances configured behind the load balancer
  • The Health Check URL setting configured with a URL that the load balancer connects to check the health of Unified Access Gateway appliance
  • Check the health of the appliance in the load balancer. Type the REST API command GET

    The response is HTTP/1.1 200 OK, if the Quiesce Mode is set to No, or HTTP/1.1 503, if the Quiesce Mode is set to Yes.

    Note: Do not use any other URL other than GET Doing so will lead to incorrect status response and resource leaks.


  1. In the admin UI Configure Manual section, click Select.
  2. In the Advanced Settings section, click the System Configuration gearbox icon.
  3. In the Quiesce Mode row, enable YES to pause the Unified Access Gateway appliance.
    When the appliance is stopped, existing sessions that the appliance is serving are honored for 10 hours, after which the sessions are closed.
  4. Click Save.


New requests that come to the load balancer are sent to next Unified Access Gateway appliance.

What to do next

Export the settings from the paused Unified Access Gateway appliance. Deploy a new version of Unified Access Gateway and import the settings. The new version of Unified Access Gateway appliance can be added to the load balancer.