Re: [Engine-devel] SSH Soft Fencing

----- Original Message ----- > From: "Barak Azulay" <bazulay(a)redhat.com&gt; > To: "Martin Perina" <mperina(a)redhat.com&gt; > Cc: "Yair Zaslavsky" <yzaslavs(a)redhat.com&gt;, engine-devel(a)ovirt.org, "Eli Mesika" <emesika(a)redhat.com&gt; > Sent: Thursday, June 27, 2013 8:31:35 PM > Subject: Re: SSH Soft Fencing > > > > ----- Original Message ----- >> From: "Eli Mesika" <emesika(a)redhat.com&gt; >> To: "Yair Zaslavsky" <yzaslavs(a)redhat.com&gt; >> Cc: "Martin Perina" <mperina(a)redhat.com&gt;, engine-devel(a)ovirt.org, "Barak >> Azulay" <bazulay(a)redhat.com&gt; >> Sent: Thursday, June 27, 2013 5:55:29 PM >> Subject: Re: SSH Soft Fencing >> >> >> >> ----- Original Message ----- >>> From: "Yair Zaslavsky" <yzaslavs(a)redhat.com&gt; >>> To: "Eli Mesika" <emesika(a)redhat.com&gt; >>> Cc: "Martin Perina" <mperina(a)redhat.com&gt;, engine-devel(a)ovirt.org, "Barak >>> Azulay" <bazulay(a)redhat.com&gt; >>> Sent: Thursday, June 27, 2013 5:43:17 PM >>> Subject: Re: SSH Soft Fencing >>> >>> >>> >>> ----- Original Message ----- >>>> From: "Eli Mesika" <emesika(a)redhat.com&gt; >>>> To: "Martin Perina" <mperina(a)redhat.com&gt; >>>> Cc: engine-devel(a)ovirt.org, "Yair Zaslavsky" <yzaslavs(a)redhat.com&gt;, >>>> "Barak >>>> Azulay" <bazulay(a)redhat.com&gt; >>>> Sent: Thursday, June 27, 2013 3:48:39 PM >>>> Subject: Re: SSH Soft Fencing >>>> >>>> >>>> >>>> ----- Original Message ----- >>>>> From: "Martin Perina" <mperina(a)redhat.com&gt; >>>>> To: engine-devel(a)ovirt.org >>>>> Cc: "Yair Zaslavsky" <yzaslavs(a)redhat.com&gt;, "Barak Azulay" >>>>> <bazulay(a)redhat.com&gt;, "Eli Mesika" <emesika(a)redhat.com&gt; >>>>> Sent: Thursday, June 27, 2013 1:51:06 PM >>>>> Subject: SSH Soft Fencing >>>>> >>>>> Hi, >>>>> >>>>> SSH Soft Fencing is a new feature for 3.3 and it tries to restart >>>>> VDSM >>>>> using SSH connection on non responsive hosts prior to real fencing. >>>>> More info can be found at >>>>> >>>>> http://www.ovirt.org/Automatic_Fencing#Automatic_Fencing_in_oVirt_3.3 >>>>> >>>>> In current SSH Soft Fencing implementation the restart VDSM using SSH >>>>> command is part of standard fencing implementation in >>>>> VdsNotRespondingTreatmentCommand. But this command is executed only >>>>> if a host has a valid PM configuration. If host doesn't have a valid >>>>> PM configuration, the execution of the command is disabled and host >>>>> state is change to Non Responsive. >>>>> >>>>> So my question are: >>>>> >>>>> 1) Should SSH Soft Fencing be executed on hosts without valid PM >>>>> configuration? >>>> >>>> I think that the answer should be yes. The vdsm restart will solve most >>>> of >>>> problems , so why not using it whether a PM agent is defined or not. >>> I agree. >>> I would like to say that I also don't like the fact that >>> VdsNotRespondingTreatment extends RestartVdsCommand. >>> One should ask if "non responding treatment is a restart vds operation" >>> or >>> maybe RestartVdsCommand is just a step in the non responding treatment >>> (inheritance vs containment/delegation). >>> I think that VdsNotRespodingTreatment should delegate the call to >>> RestartVdsCommand as the 2nd step after issuing the Soft Fencing command. >>> Thoughts anyone? >> >> That would be a nice and needed re-factoring > > I would say yes - but would add it only with appropriate configuration > (enableAutoSoftVdsmRestartWhenNoPMAvailable .... I hate the name) +1 on configuration. Configuration must reside at host-related entities (i.e - VdsStatic). Yair

> > > >> >>> >>>> >>>>> >>>>> 2) Should VDSM restart using SSH command be reimplemented >>>>> as standalone command to be usable also in other parts of engine? >>>>> If 1) is true, I think it will have to be done anyway. >>> >>> I agree here. >>>> >>>> +1 > > On one hand it makes sense, but I have several questions on the above: > - Who do we think may want to use such a command ? > - Should (or even can) we limit the use of such command to > noneResponsiveTreatment ? > > Having general commands available to all code when there is only one specific > case we are using it might be a bit riskey, > Especially when we talk about restarting something. > > Thoughts ? > > > >>>> >>>>> >>>>> >>>>> Martin Perina >>>>> >>>> >>> >> > _______________________________________________ Engine-devel mailing list Engine-devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel