Scenario: Performing a rolling restart in a highly available system

The following steps depict a typical quiesce scenario, which includes performing a rolling restart of one or many Pega 7 Platform servers.

Using a load balancer, perform the following actions:

1. Identify the Pega 7 Platform servers to be quiesced.
2. Disable the identified Pega 7 Platform servers in the load balancer.
   • The load balancer should be set to not accept new user sessions, but still allow for existing sessions to continue to work for the selected Pega 7 Platform server to be quiesced.
   • Note: Quiescing a Pega 7 Platform server that has not been disabled in the load balancer results in error conditions for users of that Pega 7 Platform server, because new users are not be able to log in. The Pega 7 Platform server must be disabled in the load balancer so that new users are redirected to another active Pega 7 Platform server.
3. Quiesce the Pega 7 Platform servers using one of the following cluster management options (for details, see Cluster management):
   • In the AES Cluster Management tab, select the Pega 7 Platform servers to be quiesced and initiate the quiesce process.
   • Use the System Management Application (SMA) Quiesce button located on the HA Cluster Management page. SMA has a user interface that uses high availability MBeans for these capabilities.
   • Use high availability MBeans that were integrated into a Network Operations Center (NOC) console.
   • Use the functionality available on the HA Cluster Management page.
4. The Pega 7 Platform servers progress through the quiesce state machine. Users passivate after periods of inactivity on the quiescing Pega 7 Platform servers and activate on new Pega 7 Platform servers in the cluster as they are sent back to the load balancer during periods of inactivity.
5. The Pega 7 Platform servers are ready for shutdown or servicing when the system run state is "Quiesce Complete" and the active user count is 0.
   • The active user count is observable in the Cluster Management display or in the MBeans.
   • Users with the quiesce investigation role are not included in the active user count. For example, a user that performs administrative functions on a quiesced Pega 7 Platform server is not be included in the count if the user has the quiesce investigation role.
6. Perform maintenance.
7. Restart the Pega 7 Platform servers when complete.
8. Enable the Pega 7 Platform servers in the load balancer to start taking traffic.

If a quiesced Pega 7 Platform server is added back into the load balancer rotation, users directed to that Pega 7 Platform server receive the following error:

Note: Users do not see this message once the Pega 7 Platform server run state is "Running."

To perform a rolling restart, start again at Step 1 and repeat the process until all remaining Pega 7 Platform servers have been restarted.

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