Steve Wray wrote:
Hi there,

Debian uses start-stop-daemon in the init scripts to, for one thing, stop services.

From the man page:

Note:  unless --pidfile is specified, start-stop-daemon behaves similar
to killall(1).  start-stop-daemon will scan the process  table  looking
for  any  processes  which  match the process name, uid, and/or gid (if
specified). Any matching process will prevent --start from starting the
daemon.  All  matching processes will be sent the KILL signal if --stop
is specified. For daemons which have long-lived children which need  to
live through a --stop you must specify a pidfile.

For example, nfs-kernel-server does not use --pidfile. It looks for nfsd processes to kill.

Suppose that the Openvz host and one of its guests were running NFS and, on the host, one were to run /etc/init.d/nfs-kernel-server stop

As I understand it this would have the side-effect of killing off the nfsd processes on the guest.

That is right, and this is just one of the reasons why we don't recommend to run anything (but the needed bare minimum like sshd) on the host system.

There is a solution and a workaround for the problem. The solution is, right, to fix bad initscripts. I mean, it's not OpenVZ-specific -- relying on process names is wrong, any user can run a process named nfsd and it should not be killed.

The workaround is to introduce a feature to hide guests' processes from the host system. This is implemented in OpenVZ kernels >= 2.6.24 as per bug #511 (http://bugzilla.openvz.org/511).
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