On 06/15/2010 03:08 PM, Joe Orton wrote: > Any opinions on this? I've had a query. > > What should "service xxxx start" do for a daemon - or more specifically, > when should it return? There is inconsistency amongst different current > init scripts, two general approaches: > > 1) fire and forget: start the daemon, return immediately > which might give "false positives" as in "service started (I've seen the OK on screen!) but not running > 2) stop and wait: start the daemon, and wait, either: > a) a short fixed period of time, or > b) in a loop until the pidfile appears, with some maximum wait time > which might give "false positives" as in "service started (also known as "pidfile exists but the process is dead") but not running" > Notable implication of (1) is that running e.g. "service xxx status" (or > stop etc) may not immediately succeed after a "start", nor may the > service be immediately usable directly after a "start" returns. > > (2b) may have surprising failure cases of an init script waiting a long > time to return - dirsrv will wait up to ten minutes, which seems rather > extreme. > > (2a) may be unreliable, being dependant on timing/machine speed > > I found at least one init scripts which also has this stop-and-wait > behaviour for "stop" (mysqld). > > I'd instinctively prefer (1) from a "do one thing and do it well" > perspective; (2) starts down the road of a better/more complex form of > service-monitoring/management and ends up doing it really badly in messy > sh script in N places. > > (A logical extension of (2) would be to require not merely that the > pidfile exists, but that the service is accepting connections on TCP > port N, before returning from the init script "start" invocation) > > Thoughts? Well, I'd say it depends on how we define the "start" part. "fire and forget", "start and make sure it was started" or "start and make sure it is running". -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
