Maintaining client version affinity during a server cluster upgrade

A non-transitory computer-readable medium containing program instructions for maintaining client version affinity during a server cluster upgrade, the program instructions for:

• receiving, by a server in the server cluster, a request from a client and checking the request for a version cookie indicating a client software version currently running on the client;
• responsive to a determination that the server is running a server software version matching the client software version, serving the request;
• responsive to a determination that the server software version does not match the client software version, forwarding the request to one of the other servers in the server cluster that is running the server software version that matches the client software version;
• and
• responsive to a determination that the client software version matches a previous server software version run by the server, initiating a software upgrade on the client instead of servicing the request, wherein initiating a software upgrade on the client further comprises instructions for:
• the server sending to the client a Client Out Of Sync Exception (COOSE) response including a new client software version, wherein only one COOSE response is sent to the client during the server cluster upgrade.

A system, comprising:

• a processing system;
• and
• a memory device coupled to the processing system and including instructions stored thereon that, in response to execution by the processing system, are operable to:
• receive, by a server in a server cluster, a request from a client and checking the request for a version cookie indicating a software version that the client is running;
• responsive to a determination that the server is running a same software version as the client, serve the request;
• responsive to a determination that the server is not running a same software version as the client, forward the request to one of other servers in the server cluster that is running the same software version as the client;
• and
• responsive to a determination that the client is running a software version matching a previous software version of the server, initiate a software upgrade on the client instead of servicing the request, wherein initiating a software upgrade on the client further comprises instructions for:
• the server sending to the client a Client Out Of Sync Exception (COOSE) response including a new client software version, wherein only one COOSE response is sent to the client during a server cluster upgrade.

A computer-implemented method for maintaining client version affinity during a server cluster upgrade, the method comprising:

• receiving, by a server in the server cluster, a request from a client and checking the request for a version cookie indicating a client software version currently running on the client;
• responsive to a determination that a server software version does not match the client software version, forwarding the request to one of other servers in the server cluster that is running the server software version that matches the client software version;
• and
• responsive to a determination that the client software version matches a previous server software version run by the server, initiating a software upgrade on the client instead of servicing the request, wherein initiating a software upgrade on the client further comprises instructions for:
• the server sending to the client a Client Out Of Sync Exception (COOSE) response including a new client software version, wherein only one COOSE response is sent to the client during the server cluster upgrade.