High Availability

ADSS Server Core

In a high availability configuration two or more ADSS Core instances can be installed with shared database so that if an instance is crashed, the other instance may take place and routine operations are not disturbed. ADSS Server Core instance performs many processes like certificate expiry alerts, certificate renewal, auto archiving, file synchronization etc. Secondary core instances will watch the primary core instance. If primary ADSS Server Core instance crashes then these tasks will be performed by secondary core instance. All ADSS Server instances use the same database and use this to check what their status is. The first installed instance of ADSS Server console automatically becomes the Primary and all subsequent instances act as Secondary.

The fields are explained as following:

Items

Description

Core High Availability

These configurations are used when the ADSS Server core is installed on multiple machines in a load balanced configuration. The high availability of the ADSS Server core is explained below in more detail.

Secondary should check Primary active status every (sec):
Secondary ADSS instance will regularly check that the Primary ADSS instance is still active. This parameter defines how often the Secondary should check the status of the Primary.
Note: At times the two or more ADSS Server core instances running in the high availability configuration are unable to connect with each other. If such a situation is occurred then make sure firewall is not blocking the access.
Number of times Secondary should re-check before becoming Primary
In case the Secondary finds the Primary to be inactive, then this parameter defines how many times it should recheck the Primary’s online status before promoting itself to become the new Primary.
Core Host:
Use the up and down buttons to re-arrange the ordering of Primary and Secondary instances. Use the remove button to delete an ADSS Server Core Host from the High Availability configuration.

The instances order can also be changed manually using Up Down arrow buttons. Select any of the Secondary instance in Core Host list and move it to top of the list and Update the settings. Once the page is updated, new Primary Core instance will start working while other instances will put in watch-dog mode.

Click Save button to complete settings

Updating ADSS Server License

To update the license file of ADSS Server in a high availability set-up it is only necessary to perform the actions on the Primary instance. The screen shot above indicates clearly which is the Primary ADSS Server instance. To update the license follow the instructions supplied with the license file on the Primary instance only. Any Secondary instances will retrieve the new license file automatically upon restart. In short, to update ADSS Server license file stop all ADSS Server Windows Services or Linux daemons on all instances (Primary and Secondary) and replace the license file found under <ADSS_Server_Home>/core directory with the new one - on the Primary instance only. Remember to take a backup of the current one before replacing it. Once done, restart the Core service and wait for one minute before starting Service and Console services/daemons. When the services/daemons have successfully started on the Primary instance proceed to start them on all Secondary instances.