License Server Failover Mechanism is mandatory in the Ephesoft Version 4.x and above.
It was optional in the previous versions.
Ephesoft failover mechanism for license servers provides high-availability in case the active license server crashes. In the earlier multi-server environment, license server runs on single machine and other client machines communicate with that server for their license validation/verification. This model works fine until license server is up and running. As soon as the hosted license server fails, all clients encounter license validation/verification problems. In addition to this, all the activities that require license validation/verification comes to a halt.
With this new enhancement in the Ephesoft Version 220.127.116.11, the application will always have an available environment where even if one license server fails then one of the backup license servers will immediately come into play and will start fulfilling all the license client requests. This transition of license server will happen on the fly (dynamically) and smoothly that a user will never know that a license server has failed as one of backup license server will immediately start processing the license validation/verification requests. It will prevent batches from going into ERROR state and will avoid task failures like web service requests, login requests, etc. Thus, user experiences no disruption in services. There is no down time due to swapping of the license servers.
To configure Failover mechanism in multi-server environment, a user will need to install fresh license with equal potential on minimum of two servers available in the multi-server environment.
To start using this feature, user will need to install failover license on minimum of two servers. After installing the license, restart all the servers one by one.
Once all the servers have been successfully started, all license requests will be processed from single license server (server A) as depicted in the below illustration.
Once the server (server A) goes down Ephesoft failover mechanism will immediately start processing requests from another available active license server in the multi-server environment. This will happen on the fly and without any disruption of normal batch execution or of any other service that require license verification/validation.
In case the server A fails, the license server is automatically swapped as shown in the below illustration.
In this way the user need not to worry about batches going into error state when one of license server goes offline, as Ephesoft License server failover mechanism will automatically handle the situation by judiciously using potential of multiple license severs available in the multi-server environment. This feature is very useful when a user needs to stop a license server for maintenance purpose as when one license server goes offline all client depending on license server will continue to work by switching to another available active license server.
To get this feature working properly in multi-server environment, heartbeat module should be running on all the servers.
Following are few common error messages seen in log file due to improper configuration and execution:
|#||Error message||Possible root cause|
|1||CPU limit exhausted. Can’t allocate more CPUs.||The total count of CPU core available in all machine in multi-server environment is greater than count specified in license installed. Get a new license with correct CPU core amount.|
|2||Invalid license for multi-server environment setup.||Either mac id of server was not included or it was entered wrong while generating license. Please verify mac id while generating license.|