----- Original Message -----
From: "Barak Azulay" <bazulay@redhat.com> To: "Martin Perina" <mperina@redhat.com> Cc: "Yair Zaslavsky" <yzaslavs@redhat.com>, engine-devel@ovirt.org, "Eli Mesika" <emesika@redhat.com> Sent: Sunday, June 30, 2013 7:35:22 PM Subject: Re: SSH Soft Fencing
----- Original Message -----
From: "Barak Azulay" <bazulay@redhat.com> To: "Martin Perina" <mperina@redhat.com> Cc: "Yair Zaslavsky" <yzaslavs@redhat.com>, engine-devel@ovirt.org, "Eli Mesika" <emesika@redhat.com> Sent: Thursday, June 27, 2013 8:31:35 PM Subject: Re: SSH Soft Fencing
----- Original Message -----
From: "Eli Mesika" <emesika@redhat.com> To: "Yair Zaslavsky" <yzaslavs@redhat.com> Cc: "Martin Perina" <mperina@redhat.com>, engine-devel@ovirt.org, "Barak Azulay" <bazulay@redhat.com> Sent: Thursday, June 27, 2013 5:55:29 PM Subject: Re: SSH Soft Fencing
----- Original Message -----
From: "Yair Zaslavsky" <yzaslavs@redhat.com> To: "Eli Mesika" <emesika@redhat.com> Cc: "Martin Perina" <mperina@redhat.com>, engine-devel@ovirt.org, "Barak Azulay" <bazulay@redhat.com> Sent: Thursday, June 27, 2013 5:43:17 PM Subject: Re: SSH Soft Fencing
----- Original Message -----
From: "Eli Mesika" <emesika@redhat.com> To: "Martin Perina" <mperina@redhat.com> Cc: engine-devel@ovirt.org, "Yair Zaslavsky" <yzaslavs@redhat.com>, "Barak Azulay" <bazulay@redhat.com> Sent: Thursday, June 27, 2013 3:48:39 PM Subject: Re: SSH Soft Fencing
----- Original Message -----
From: "Martin Perina" <mperina@redhat.com> To: engine-devel@ovirt.org Cc: "Yair Zaslavsky" <yzaslavs@redhat.com>, "Barak Azulay" <bazulay@redhat.com>, "Eli Mesika" <emesika@redhat.com> 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)
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 ?
Yes, I think we should limit that 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.
We can keep this internal and not expose it to the user, just implement explicitly in non responding treatment
Martin ? Eli? Yair?
Can you please refer to the issue above ?
Thoughts ?
Martin Perina