* Update last agents during ms maintenance, and some code improvements
* Send 503 (Service Unavailable) response status when maintenance or shutdown is initiated
[Any load balancer in the clustered environment can avoid routing requests to this MS node]
* Migrate systemvm agents before routing host agents, and some code improvements
* Added events for ms maintenance and shutdown operations
* Added the following ms maintenance and shutdown improvements
- block new agent connections during prepare for maintenance of ms
- maintain avoids ms list
- propagate updated management servers list and lb algorithm in host and indirect.agent.lb.algorithm settings respectively, to systemvm (non-routing) agents
- updated setup ms list and migrate agent connections to executor service
- migrate agent connection through executor, and send the answer to the ms host that initiated the migration
- re-initialize ssl handshake executor if it is shutdown
- don't allow prepare for maintenance or shutdown when other management server nodes are in preparing states
- don't allow trigger shutdown when management server is up and other management server nodes are in preparing states
- stop agent connections monitor on ms maintenance
- update avoid ms list in ready command
- updated connected host from the client connection
- update last agents in ms metrics from the database
- updated some agent config descriptions
- update last management server in the hosts during shutdown
- added agents and lastagents in management server response
- updated management server maintenance & shutdown unit tests
- some code improvements
* refactored code / addressed comments
* removed shutdown testcase (maybe, calling System.exit)
* Revert "removed shutdown testcase (maybe, calling System.exit)"
This reverts commit e14b071715.
* avoid system.exit during shutdown test
* code improvements
* testcase fix
* Fix cutoff time in agent connections monitor thread
* Support for Management Server Maintenance
- New APIs: prepareForMaintenance and cancelMaintenance, with required parameter - managementserverid.
- New management server states for maintenance: PreparingForMaintenance, Maintenance.
- listHosts API with optional parameter – managementserverid, to list the hosts connected to the management server.
- Support management server maintenance when more than one active management servers available.
- Triggers transfer agents to other available management servers for maintenance, new agent command MigrateAgentConnectionCommand to initiate transfer of indirect agents.
- New global config 'management.server.maintenance.timeout', to set the timeout (in mins) for the management server maintenance window, default: 60 mins.
- UI changes: Prepare and Cancel Maintenance in Management Server section, Connected Agents tab, New fields for hosts and management servers.
* Updated pending jobs check timer task with ScheduledExecutorService
* keep maintenance state on trigger shutdown call when ms is in maintenance
* add pending jobs count to ms response
* during ms heartbeat, update state to up only when it's down
* allow vm work jobs of async job created before prepare for maintenance
* Revert "keep maintenance state on trigger shutdown call when ms is in maintenance"
This reverts commit 607e13364679eac897f4d146bb3325ea7a61ba17.
* skip maintenance test when multiple management servers are not available, and not configured in host setting for kvm
Suresh Kumar Anaparti