Symptoms

K2 blackpearl Server service keep stopping for unknown reason requiring manual intervention to start it again.
 

Diagnoses

This can be caused by variety of reasons but one of the possible causes is inability of K2 server to connect to K2 DB. In that scenario it will shutdown itself gracefully logging appropriate error in log.

You can verify/confirm this by analyzing K2 host server logs where it will be possible to see root cause of this issue, i.e. specific error messages in host server log indicating that K2 service has been stopped due to inability to connect to K2 DB:

"2006 Error Connecting to Database. Please restart Host Server when Database becomes available"

This means that it is necessary to check what's wrong with SQL server or connectivity between K2 server and SQL server involving infrastructure/SQL administrator(s). You may also try to look for any specific errors on SQL server hosting K2 DB logged at the time when K2 server logs "2006 Error Connecting to Database. Please restart Host Server when Database becomes available" error.
 

Resolution

Check K2 host server log for presence of error "2006 Error Connecting to Database. Please restart Host Server when Database becomes available" - see details above.