Le 21/09/2018 à 05:35, dick balaska a écrit :
> On 09/08/2018 09:07 AM, dick balaska wrote:
> 
>>
>> Now if the vpn dies, the queued frames keep chugging, and if a machine
>> reboots he just restarts and goes. yay.
> 
> Ah, computers...
> 
> The bsacs service (renderfarm server) fails to launch povrayws on reboot.
> If I stop/start it by hand, it works.
> If I upgrade, the system stops, upgrades, and starts the service correctly.
> But on reboot, no.  wtf.
> 
violent shutdown for reboot have a trend to leave some files behind them 
which make the system believe the process is already running.

Typical wtf:
1. the start process write the psid in a file
2. on clean shutdown, file with psid is deleted
3. system upgrades cleanly stop all processes before restart (see 2)
4. on power-reboot, file with psid exist, so the system is happy and do 
nothing.

The basic solution is that the psid in the file should also be checked 
to see:
1. Is such psid currently in use (does the process exist)
2. Is such process matching the command that is associated with the file 
(collisions on psid can occurs, there is only 65535 id, and they get reused)

Especially after a power-reboot, in which more processes are forked at 
start to check the disks, so another service can now use the psid logged 
in the file in the previous session.

When you forget point 2, you get problem, randomly.

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