[ovirt-devel] Debug vdsm 4.0.0 report error: libvirt: XML-RPC error : Failed to connect socket to '/var/run/libvirt/libvirt-sock': Permission denied

Michal Skrivanek mskrivan at redhat.com
Tue Jul 26 03:37:54 EDT 2016


> On 26 Jul 2016, at 08:50, lifuqiong <lifuqiong at cncloudsec.com> wrote:
> 
>  
> On 26 Jul 2016, at 08:02, lifuqiong <lifuqiong at cncloudsec.com <mailto:lifuqiong at cncloudsec.com>> wrote:
>  
>  
> I do make a mistake because I just print os.getuid() show the user root; but os.geteuid() show the current user is still vdsm;
>  
> Anyway , I still don’t know how to debug vdsm, I cann’t log in to centos with user VDSM, because I don’t know the passwd of user vdsm and if I changed the password, the service vdsmd will cann’t start.
>  
> the vdsm account is intentionally disabled for interactive login
> 
> 
>  
> You told me “should follow the devel setup wiki” , what’s the true link of vdsm devel setup wiki ?  I can’t get useful information in ovirt.org <http://ovirt.org/> or google.
>  
> http://www.ovirt.org/develop/developer-guide/vdsm/developers/ <http://www.ovirt.org/develop/developer-guide/vdsm/developers/> has tips how to build from source and what packages are needed
> Anything specific you’re troubleshooting?
>  
>          I do build the source from this instruction , but I want to set breakpoint to view each step and variable value to understand the vdsm’s code using python IDE such as Pycharm , 
>  
> You know that we can implement this debug requirement in ovirt engine easily, but I can’t implement local debug in vdsm easily, because vdsm didn’t allow root to run or debug.
>  
> Is there any debug instruction ?

I don’t think it’s possible to debug it from PyCharm, or any IDE for that matter, easily. 
It’s a multithreaded application, you can’t really set a breakpoint without affecting other functionality since some of the threads need to keep running
Best advice is to add a debugging/logging code in places you need, printing variables you’re interested in.

Thanks,
michal

>  
> Thank you
> Mark
>  
> Thanks,
> michal
> 
> 
>  
>  
> Thank you
>  
> 发件人: Michal Skrivanek [mailto:mskrivan at redhat.com <mailto:mskrivan at redhat.com>] 
> 发送时间: 2016年7月26日 5:00
> 收件人: lifuqiong
> 抄送: users; devel
> 主题: Re: [ovirt-devel] Debug vdsm 4.0.0 report error: libvirt: XML-RPC error : Failed to connect socket to '/var/run/libvirt/libvirt-sock': Permission denied
>  
>  
> 
> On 25 Jul 2016, at 21:50, Sandro Bonazzola <sbonazzo at redhat.com <mailto:sbonazzo at redhat.com>> wrote:
> 
> Adding some people from virt team.
> Il 23/Lug/2016 11:44, "lifuqiong" <lifuqiong at cncloudsec.com <mailto:lifuqiong at cncloudsec.com>> ha scritto:
> >
> > I debugged vdsm with PyCharm, And I logged on my Centos 7.2 with root,  and get an error as follows:
> >
> >  
> >
> > Problem:
> >
> >  
> >
> > Traceback (most recent call last):
> >
> >   File "/usr/share/vdsm/vdsm", line 149, in run
> >
> >     serve_clients(log)
> >
> >   File "/usr/share/vdsm/vdsm", line 104, in serve_clients
> >
> >     cif = clientIF.getInstance(irs, log, scheduler)
> >
> >   File "/usr/share/vdsm/clientIF.py", line 204, in getInstance
> >
> >     cls._instance = clientIF(irs, log, scheduler)
> >
> >   File "/usr/share/vdsm/clientIF.py", line 106, in __init__
> >
> >     secret.clear()
> >
> >   File "/usr/lib/python2.7/site-packages/vdsm/virt/secret.py", line 92, in clear
> >
> >     con = libvirtconnection.get()
> >
> >   File "/usr/lib/python2.7/site-packages/vdsm/libvirtconnection.py", line 163, in get
> >
> >     password)
> >
> >   File "/usr/lib/python2.7/site-packages/vdsm/libvirtconnection.py", line 99, in open_connection
> >
> >     return utils.retry(libvirtOpen, timeout=10, sleep=0.2)
> >
> >   File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 546, in retry
> >
> >     return func()
> >
> >   File "/usr/lib64/python2.7/site-packages/libvirt.py", line 105, in openAuth
> >
> >     if ret is None:raise libvirtError('virConnectOpenAuth() failed')
> >
> > libvirtError: Failed to connect socket to '/var/run/libvirt/libvirt-sock': Permission denied
> >
> >  
> >
> > Investitate:
> >
> > According to the traceback above, the code in libvirt.py as below, and  os.geteuid() get ‘0’ which shows the current user is root;
>  
> vdsm is not supposed to be run under root user. For debugging you should follow the devel setup wiki and not change a regular host. 
> Depends what you modified, it's impossible to say from what you described....but a general advice is you simply don't do that:)
> 
> 
> >
> >  
> >
> > def openAuth(uri, auth, flags=0):
> >
> >          #print os.geteuid()
> >
> >     ret = libvirtmod.virConnectOpenAuth(uri, auth, flags)
> >
> >     if ret is None:raise libvirtError('virConnectOpenAuth() failed')
> >
> > return virConnect(_obj=ret)
> >
> >  
> >
> > [root at server117 libvirt]# ll /var/run/libvirt/libvirt-sock
> >
> > srwxrwx---. 1 root qemu 0 Jul 19 23:43 /var/run/libvirt/libvirt-sock
> >
> >  
> >
> > According that, root should not get an Permission denied error ? But why?
> >
> >  
> >
> > And I setenforce=0 , and still show Perssion denied error.
> >
> >  
> >
> > What’s the reason? And how to solve it?
> >
> >  
> >
> > Thank you.
> >
> >
> > _______________________________________________
> > Devel mailing list
> > Devel at ovirt.org <mailto:Devel at ovirt.org>
> > http://lists.ovirt.org/mailman/listinfo/devel <http://lists.ovirt.org/mailman/listinfo/devel>
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