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https://bugzilla.redhat.com/show_bug.cgi?id=1200149 Even though we have a mutex mechanism so that two clients don't spawn two daemons, it's not strong enough. It can happen that while one client is spawning the daemon, the other one fails to connect. Basically two possible errors can happen: error: Failed to connect socket to '/home/mprivozn/.cache/libvirt/libvirt-sock': Connection refused or: error: Failed to connect socket to '/home/mprivozn/.cache/libvirt/libvirt-sock': No such file or directory The problem in both cases is, the daemon is only starting up, while we are trying to connect (and fail). We should postpone the connecting phase until the daemon is started (by the other thread that is spawning it). In order to do that, create a file lock 'libvirt-lock' in the directory where session daemon would create its socket. So even when called from multiple processes, spawning a daemon will serialize on the file lock. So only the first to come will spawn the daemon. Tested-by: Richard W. M. Jones <rjones@redhat.com> Signed-off-by: Michal Privoznik <mprivozn@redhat.com> (cherry picked from commit be78814ae07f092d9c4e71fd82dd1947aba2f029)
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>