[PVE-User] proxmox serverfarm - how?

[PVE-User] proxmox serverfarm - how?

[Roland privat]

hello, 

we want to build an experimental dynamic „datacenter“ in our makerspace (mostly for academic purpose), where the number of nodes online depends on energy availability, heat demand, processing demand, .... , but if i see this right a proxmox cluster needs half of the nodes +1 online to have quorum, i.e. for example we wont be able to start a vm if only two out of 10 nodes are online. 

what‘s the best way to solve this, i.e. what is the most secure/consistent way? 

eg for a cluster of 10 nodes, what about adding 10 virtual proxmox dummy nodes or qdevice instances in another location (so one single physical host online has quorum) instead of tuning node/quorum number in corosync configuration? 

what we want is a „farm“ but not a cluster. but we want centralized management and vm migration. 

regards
roland

Re: [PVE-User] proxmox serverfarm - how?

[aderumier]

Hi, if you have something central, knowning exactly how much nodes are
currently running, and stop/starting them dynamically

you could play with "pvecm expected X"  to tell how many vote you need
to have quorum.

(for example, you have 10 nodes builded in corosync,  you shutdown 5 of
them --> so no quorum,   just use "pvecm expected 5")


Le mercredi 03 mars 2021 à 08:25 +0100, Roland privat a écrit :
> hello, 
> 
> we want to build an experimental dynamic „datacenter“ in our
> makerspace (mostly for academic purpose), where the number of nodes
> online depends on energy availability, heat demand, processing
> demand, .... , but if i see this right a proxmox cluster needs half
> of the nodes +1 online to have quorum, i.e. for example we wont be
> able to start a vm if only two out of 10 nodes are online. 
> 
> what‘s the best way to solve this, i.e. what is the most
> secure/consistent way? 
> 
> eg for a cluster of 10 nodes, what about adding 10 virtual proxmox
> dummy nodes or qdevice instances in another location (so one single
> physical host online has quorum) instead of tuning node/quorum number
> in corosync configuration? 
> 
> what we want is a „farm“ but not a cluster. but we want centralized
> management and vm migration. 
> 
> regards
> roland
> 
> _______________________________________________
> pve-user mailing list
> pve-user@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user

Re: [PVE-User] proxmox serverfarm - how?

[Roland]

the question for me is, what can go wrong this way or in what way
clustering conflicts with the idea of running a "temporary server farm"
which is shutdown completely for long periods.

what happens for example if i set "pvecm expected 1"  and
startup/shutdown different individual servers or pairs of servers? i
think that won't fit...

when setting "pvecm expected 1" , wouldn't we need to know which
server(s) of the farm was being used last and shutdown last?

so, rethinking about this - doesn't it make sense to have something up
and running independently of that farm for maintaining cluster
state/node information?

what about adding one or two rasberry pi or two virtual maschines "on
some other, independent pve systems" as quorum/qdevice , setting "pvecm
expected 1 or 2" then and have proper backup for these ? can we
use/install virtual instances of proxmox for this ?

regards
roland


Am 03.03.21 um 09:28 schrieb aderumier@odiso.com:
> Hi, if you have something central, knowning exactly how much nodes are
> currently running, and stop/starting them dynamically
>
> you could play with "pvecm expected X"  to tell how many vote you need
> to have quorum.
>
> (for example, you have 10 nodes builded in corosync,  you shutdown 5 of
> them --> so no quorum,   just use "pvecm expected 5")
>
>
> Le mercredi 03 mars 2021 à 08:25 +0100, Roland privat a écrit :
>> hello,
>>
>> we want to build an experimental dynamic „datacenter“ in our
>> makerspace (mostly for academic purpose), where the number of nodes
>> online depends on energy availability, heat demand, processing
>> demand, .... , but if i see this right a proxmox cluster needs half
>> of the nodes +1 online to have quorum, i.e. for example we wont be
>> able to start a vm if only two out of 10 nodes are online.
>>
>> what‘s the best way to solve this, i.e. what is the most
>> secure/consistent way?
>>
>> eg for a cluster of 10 nodes, what about adding 10 virtual proxmox
>> dummy nodes or qdevice instances in another location (so one single
>> physical host online has quorum) instead of tuning node/quorum number
>> in corosync configuration?
>>
>> what we want is a „farm“ but not a cluster. but we want centralized
>> management and vm migration.
>>
>> regards
>> roland
>>
>> _______________________________________________
>> pve-user mailing list
>> pve-user@lists.proxmox.com
>> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user
> _______________________________________________
> pve-user mailing list
> pve-user@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user

Re: [PVE-User] proxmox serverfarm - how?

[Roland]

yes, that's what i would expect to happen and i'd like to avoid.

Am 03.03.21 um 12:42 schrieb Humberto Jose de Sousa via pve-user:
>
> Re: [PVE-User] proxmox serverfarm - how?.eml
>
> Betreff:
> Re: [PVE-User] proxmox serverfarm - how?
> Von:
> Humberto Jose de Sousa <humbertos@ifsc.edu.br>
> Datum:
> 03.03.21, 12:42
>
> An:
> Proxmox VE user list <pve-user@lists.proxmox.com>
>
>
> The worst thing that may happen is a split brain cluster if you set "pvecm
> expected 1"
>
> Em qua., 3 de mar. de 2021 às 08:26, Roland<devzero@web.de>  escreveu:
>
>> the question for me is, what can go wrong this way or in what way
>> clustering conflicts with the idea of running a "temporary server farm"
>> which is shutdown completely for long periods.
>>
>> what happens for example if i set "pvecm expected 1"  and
>> startup/shutdown different individual servers or pairs of servers? i
>> think that won't fit...
>>
>> when setting "pvecm expected 1" , wouldn't we need to know which
>> server(s) of the farm was being used last and shutdown last?
>>
>> so, rethinking about this - doesn't it make sense to have something up
>> and running independently of that farm for maintaining cluster
>> state/node information?
>>
>> what about adding one or two rasberry pi or two virtual maschines "on
>> some other, independent pve systems" as quorum/qdevice , setting "pvecm
>> expected 1 or 2" then and have proper backup for these ? can we
>> use/install virtual instances of proxmox for this ?
>>
>> regards
>> roland
>>
>>
>> Am 03.03.21 um 09:28 schriebaderumier@odiso.com:
>>> Hi, if you have something central, knowning exactly how much nodes are
>>> currently running, and stop/starting them dynamically
>>>
>>> you could play with "pvecm expected X"  to tell how many vote you need
>>> to have quorum.
>>>
>>> (for example, you have 10 nodes builded in corosync,  you shutdown 5 of
>>> them --> so no quorum,   just use "pvecm expected 5")
>>>
>>>
>>> Le mercredi 03 mars 2021 à 08:25 +0100, Roland privat a écrit :
>>>> hello,
>>>>
>>>> we want to build an experimental dynamic „datacenter“ in our
>>>> makerspace (mostly for academic purpose), where the number of nodes
>>>> online depends on energy availability, heat demand, processing
>>>> demand, .... , but if i see this right a proxmox cluster needs half
>>>> of the nodes +1 online to have quorum, i.e. for example we wont be
>>>> able to start a vm if only two out of 10 nodes are online.
>>>>
>>>> what‘s the best way to solve this, i.e. what is the most
>>>> secure/consistent way?
>>>>
>>>> eg for a cluster of 10 nodes, what about adding 10 virtual proxmox
>>>> dummy nodes or qdevice instances in another location (so one single
>>>> physical host online has quorum) instead of tuning node/quorum number
>>>> in corosync configuration?
>>>>
>>>> what we want is a „farm“ but not a cluster. but we want centralized
>>>> management and vm migration.
>>>>
>>>> regards
>>>> roland
>>>>
>>>> _______________________________________________
>>>> pve-user mailing list
>>>> pve-user@lists.proxmox.com
>>>> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user
>>> _______________________________________________
>>> pve-user mailing list
>>> pve-user@lists.proxmox.com
>>> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user
>> _______________________________________________
>> pve-user mailing list
>> pve-user@lists.proxmox.com
>> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user
>>
>
> _______________________________________________
> pve-user mailing list
> pve-user@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user