OpenVZ and the Ubuntu Upstart init daemon

[Kir Kolyshkin]

Scott James Remnant wrote:
> On Mon, 2007-04-09 at 15:33 +0400, Kir Kolyshkin wrote:
>
>   
>> From the other side, I do not understand why mountall.sh script sends
>> a
>> (USR1) signal to upstart which upstart can not receive (as there's no 
>> handler).
>>
>>     
> Because it was written for sysvinit.
>
> USR1 is a strange signal that tells it to close /dev/initctl and open it
> again; upstart has no fifo in /dev, so doesn't need to implement this
> signal.
>
> The default init signal semantics mean it's ignored.
>   
We will definitely fix signal handing in our kernels; still I suggest 
you to workaround this "init vs. upstart compatibility" feature by 
providing a dummy handler for USR1. This might help in other situations 
(init in chroot, Linux-VServer, FreeVPS, etc.).

BTW AFAIK "classic" init in chroot works just fine when run with some 
non-documented flag telling it to ignore the fact its getpid() != 1 (I 
forgot the flag as it was a few years ago). That _probably_ means init 
is not relying on kernel's special semantics for PID #1.