[PVE-User] Question about Proxmox HA

[athompso at athompso.net]

Short answer: because some of us just want the flexibility of taking a node down for maintenance and have enough safety built into the system that we don't care if one node goes haywire.
I'll probably retract that statement the first time a node goes haywire in a way that damages data.
My quorum connection is over the same network (bond0) as storage and client VM I/O, so I'm trusting that if a node fails in a way that results in split-brain, it'll be self-isolating anyway.
I could be wrong, but downtime is only an inconvenience for me right now, not critical.
(Having said all that, I do use IPMI fencing because it's available.)
-Adam

On Dec 6, 2013 6:58 PM, David Thompson <david at digitaltransitions.ca> wrote:
>
> I can’t understand why one would build a HA cluster without fencing. I’ve just finished building a HA cluster myself with IPMI fencing and I see the fencing section as being the pivotal point for the whole setup to work properly.
>
> I can only assume that if your node(s) go down, then they stay down and you have to manually interject and power them up. Correct?
>
> Perhaps for a testing environment it might do, but if you’re testing a system to deploy in production, wouldn’t one want to have the base (perhaps not production hardware), but at a minimum the type of same software you’d want to use? In this case IPMI enabled fencing, NFS backend storage, and proxmox servers clustered? —> Or something of similar abilities.
>
> the fence_ipmilan section with the “power_wait” option seems to be the crux that holds this all together efficiently, at least for those who are using ipmi for fencing.
>
> Sorry, not trying to sound sarcastic and I apologize if I do, just trying to figure out why one would build a system without the security that fencing provides to HA for failover with the added ability to bring servers back online automatically… Perhaps you or someone else here can explain this more to me as to why one would do this. Just trying to get a good solid grasp on HA clusters and different configurations that can be done with them.
>
> Thanks,
>
> David
>
> On Dec 6, 2013, at 3:23 PM, Gilberto Nunes <gilberto.nunes32 at gmail.com> wrote:
>
>> I meant: I get it!!!
>>
>> That's work pretty awsome!!!
>>
>>
>> 2013/11/10 Gilberto Nunes <gilberto.nunes32 at gmail.com>
>>>
>>> That's cool ahmad...
>>>
>>> I will try it as soon as I can...
>>>
>>> Thanks 
>>>
>>>
>>> 2013/11/10 ahmad imanudin <ahmadiman1126 at gmail.com>
>>>>>
>>>>>
>>>>> ----------------------------------------------------------------------
>>>>>
>>>>> Message: 1
>>>>> Date: Fri, 8 Nov 2013 11:40:58 -0200
>>>>> From: Gilberto Nunes <gilberto.nunes32 at gmail.com>
>>>>> To: pve-user at pve.proxmox.com
>>>>> Subject: [PVE-User] Question about Proxmox HA
>>>>> Message-ID:
>>>>>         <CAOKSTBt9Qr05nRKnYpEX2ksQjLL0D_JabRoDYy4N3NUEgs3i6Q at mail.gmail.com>
>>>>> Content-Type: text/plain; charset=ISO-8859-1
>>>>>
>>>>>
>>>>> Hello
>>>>>
>>>>> We have here a cluster created with 3 nodes and a simple storage...
>>>>> It's just to test porposes...
>>>>> There is no fence devices, for now.
>>>>> After setting up all Proxmox Hosts and VM's, when I turn off a VM on
>>>>> node1, for example, the VM is started on node2.
>>>>> But when I plugged off the network cable, the some doesn't happen!
>>>>>
>>>>> Why? Because the cluster is without fence device??
>>>>>
>>>>> Thanks...
>>>>
>>>>
>>>> Hi Gilberto,
>>>>
>>>> I Have been testing Proxmox HA without fencing device and works. I test with 2 nodes Proxmox but have not tried with 3 nodes. I also posting in my blog about howto : http://ahmad.imanudin.com/2013/08/18/tips-proxmox-configure-proxmox-high-availability-without-fencing-device/ with indonesian language :D
>>>>
>>>> This is my Cluster configuration
>>>> *************************************
>>>> cp /etc/pve/cluster.conf /etc/pve/cluster.conf.new
>>>> nano /etc/pve/cluster.conf.new
>>>>
>>>> <?xml version="1.0"?>
>>>> <cluster config_version="5" name="excellent">
>>>> <cman expected_votes="1" keyfile="/var/lib/pve-cluster/corosync.authkey" two_node="1"/>
>>>> <fencedevices>
>>>> <fencedevice agent="fence_manual" name="human"/>
>>>> </fencedevices>
>>>> <clusternodes>
>>>> <clusternode name="pve1" nodeid="1" votes="1">
>>>> <fence>
>>>> <method name="single">
>>>> <device name="human" nodename="pve1"/>
>>>> </method>
>>>> </fence>
>>>> </clusternode>
>>>> <clusternode name="pve2" nodeid="2" votes="1">
>>>> <fence>
>>>> <method name="single">
>>>> <device name="human" nodename="pve2"/>
>>>> </method>
>>>> </fence>
>>>> </clusternode>
>>>> </clusternodes>
>>>> </cluster>
>>>>
>>>> Note : 
>>>> excellent = My Cluster name
>>>> pve1 = Hostname for Proxmox 1 (node 1)
>>>> pve2 = Hostname for Proxmox 2 (node 2)
>>>>
>>>> Importan : You must edit config_version every change cluster configuration.
>>>>
>>>> Next you can configure VM with clue from here : http://pve.proxmox.com/wiki/High_Availability_Cluster and try to power off host Proxmox.
>>>> Example :
>>>>
>>>> I have VM running on Proxmox 1 (node1) and have been configured HA. Forced off node 1 and run this command from node 2 to take over VM
>>>>
>>>> fence_ack_manual pve1 (pve1 is hostname node 1)
>>>>
>>>> after that, you must confirm with answer absolutely
>>>>
>>>> Thanks
>>>>
>>>> -- 
>>>>
>>>>
>>>> **
>>>> Best Regards,
>>>>
>>>>
>>>> Ahmad Imanudin -  Sharing is Beautiful !
>>>> Web : http://ahmad.imanudin.com, YM : ahmad_imanudin
>>>> FB : http://facebook.com/imanudin11 Twitter : @ahmad_9111 
>>>>
>>>> _______________________________________________
>>>> pve-user mailing list
>>>> pve-user at pve.proxmox.com
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>>>>
>>>
>>>
>>>
>>> -- 
>>> Gilberto Ferreira
>>
>>
>>
>>
>> -- 
>> Gilberto Ferreira
>> _______________________________________________
>> pve-user mailing list
>> pve-user at pve.proxmox.com
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