[libvirt] Is DBus a hard dependency

[Guido Günther]

On Mon, Nov 26, 2012 at 10:33:15AM +0000, Daniel P. Berrange wrote:
> On Sat, Nov 24, 2012 at 06:34:35PM +0100, Guido Günther wrote:
> > Hi,
> > currently running libvirtd without DBus fails due to:
> > 
> > error : nwfilterDriverStartup:208 : DBus matches could not be installed. Disabling nwfilter driver
> > error : virDBusGetSystemBus:77 : internal error Unable to get DBus system bus connection: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory
> > error : virStateInitialize:810 : Initialization of NWFilter state driver failed
> > error : daemonRunStateInit:784 : Driver state initialization failed
> > 
> > because we fail driver initialization hard in nwfilter_driver.c:
> > 
> >     if (nwfilterDriverInstallDBusMatches(sysbus) < 0) {
> >         VIR_ERROR(_("DBus matches could not be installed. Disabling nwfilter "
> >                   "driver"));
> >         /*
> >          * unfortunately this is fatal since virNWFilterTechDriversInit
> >          * may have caused the ebiptables driver to use the firewall tool
> >          * but now that the watches don't work, we just disable the nwfilter
> >          * driver
> >          */
> >         goto error;
> >     }
> > 
> > I wonder if this on prupose or if we can just make this a soft error and
> > go on without DBus? At least in the !HAVE_FIREWALLD case it should be
> > o.k. to continue. Shouldn't it? See attached patch.
> 
> Generally, if DBus has been requested at compile time, it ought to
> be treated as compulsory, otherwise it should be non-fatal.

Thanks. Good to know.

> 
> 
> > >From 22571860568bfe8026e60dcede8f332ec6fd002f Mon Sep 17 00:00:00 2001
> > Message-Id: <22571860568bfe8026e60dcede8f332ec6fd002f.1353774807.git.agx at sigxcpu.org>
> > From: =?UTF-8?q?Guido=20G=C3=BCnther?= <agx at sigxcpu.org>
> > Date: Sat, 24 Nov 2012 17:32:59 +0100
> > Subject: [PATCH] nwfilter: Allow DBus initialization to fail
> > To: libvir-list at redhat.com
> > 
> > in case we don't use firewalld. This allows us to run without
> > DBus on servers.
> > ---
> >  src/nwfilter/nwfilter_driver.c |    2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/src/nwfilter/nwfilter_driver.c b/src/nwfilter/nwfilter_driver.c
> > index 12f47ef..e4f6ec9 100644
> > --- a/src/nwfilter/nwfilter_driver.c
> > +++ b/src/nwfilter/nwfilter_driver.c
> > @@ -204,6 +204,7 @@ nwfilterDriverStartup(int privileged)
> >       * initializing
> >       */
> >      if (nwfilterDriverInstallDBusMatches(sysbus) < 0) {
> > +#if HAVE_FIREWALLD
> >          VIR_ERROR(_("DBus matches could not be installed. Disabling nwfilter "
> >                    "driver"));
> >          /*
> > @@ -213,6 +214,7 @@ nwfilterDriverStartup(int privileged)
> >           * driver
> >           */
> >          goto error;
> > +#endif
> >      }
> 
> IMHO any conditional should be in the nwfilterDriverInstallDBusMatches method
> itself. ie that method should be a no-op hardcoded to return 0, if firewalld
> has been disabled at compile time.

It turns out that this is already the case - I missed it since I only
tested with this patch and --without-firewalld. 

So building --with-firewalld currently needs dbus and firewalld for
libvirtd to actually start.
Thanks,
 -- Guido

> 
> Daniel
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