8:07 p.m.
On 06/27/2013 05:43 PM, Yair Zaslavsky wrote:
----- Original Message -----
> From: "Eli Mesika" <emesika(a)redhat.com>
> To: "Martin Perina" <mperina(a)redhat.com>
> Cc: engine-devel(a)ovirt.org, "Yair Zaslavsky" <yzaslavs(a)redhat.com>,
"Barak Azulay" <bazulay(a)redhat.com>
> Sent: Thursday, June 27, 2013 3:48:39 PM
> Subject: Re: SSH Soft Fencing
>
>
>
> ----- Original Message -----
>> From: "Martin Perina" <mperina(a)redhat.com>
>> To: engine-devel(a)ovirt.org
>> Cc: "Yair Zaslavsky" <yzaslavs(a)redhat.com>, "Barak
Azulay"
>> <bazulay(a)redhat.com>, "Eli Mesika" <emesika(a)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?
I agree.
The purpose of this feature is to add escalation step when handling non
responsive host.
Power fencing is only a step in the escalation flow. so should be called
from within the main flow controller (the VdsNotRespodingTreatment).
Maybe we'd like this to be fine tuned by a custom policy in future versions.
>
>>
>> 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
+1
The VDSM restart is a step in the escalation flow, and it should not be
tightly coupled with the non-responsive treatment implementation.
>
>>
>>
>> Martin Perina
>>
>
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