on 20/08/2011 13:02 Andriy Gapon said the following: > on 18/08/2011 02:15 Steven Hartland said the following: >> In a nutshell the jail manager we're using will attempt to resurrect the jail >> from a dieing state in a few specific scenarios. >> >> Here's an exmaple:- >> 1. jail restart requested >> 2. jail is stopped, so the java processes is killed off, but active tcp >> sessions >> may prevent the timely full shutdown of the jail. >> 3. if an existing jail is detected, i.e. a dieing jail from #2, instead of >> starting a new jail we attach to the old one and exec the new java process. >> 4. if an existing jail isnt detected, i.e. where there where not hanging tcp >> sessions and #2 cleanly shutdown the jail, a new jail is created, attached to >> and the java exec'ed. >> >> The system uses static jailid's so its possible to determine if an existing >> jail for this "service" exists or not. This prevents duplicate services as >> well as making services easy to identify by their jailid. >> >> So what we could be seeing is a race between the jail shutdown and the attach >> of the new process? > > Not a jail expert at all, but a few suggestions... > > First, wouldn't the 'persist' jail option simplify your life a little bit? > > Second, you may want to try to monitor value of prison0.pr_uref variable (e.g. > via kgdb) while executing various scenarios of what you do now. If after > finishing a certain scenario you end up with a value lower than at the start > of > scenario, then this is the troublesome one. > Please note that prison0.pr_uref is composed from a number of non-jailed > processes plus a number of top-level jails. So take this into account when > comparing prison0.pr_uref values - it's better to record the initial value > when > no jails are started and it's important to keep the number of non-jailed > processes the same (or to account for its changes).
BTW, I suspect the following scenario, but I am not able to verify it either via testing or in the code: - last process in a dying jail exits - pr_uref of the jail reaches zero - pr_uref of prison0 gets decremented - you attach to the jail and resurrect it - but pr_uref of prison0 stays decremented Repeat this enough times and prison0.pr_uref reaches zero. To reach zero even sooner just kill enough of non-jailed processes. -- Andriy Gapon _______________________________________________ freebsd-jail@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-jail To unsubscribe, send any mail to "freebsd-jail-unsubscr...@freebsd.org"
