[PVE-User] DRS proxmox

[Thomas Lamprecht]

Hi,

On 04/05/2016 12:03 PM, Mohamed Sadok Ben Jazia wrote:
> Thank you Thomas
> I'm going to describe my thoughts about the DRS based on the project i'm
> working on, and i was stuck in this step.
> Starting from many clusters in different sub nets and locations, i want
> create a large number of LXC containers for my clients.
> So for one cluster with many nodes and shared storage, it's a greedy
> algorithm with best matches, and by considering the LXC live migration is
> not yet available, this is what i'm doing:
>
> For each new container, or re-sizing an old one, i loop all available nodes
> in the cluster and see the one that uses more ressources without reaching
> the max possible hardware resources, in order to make nodes full.
> Optimization of this method is doing a silent migration when a container is
> rebooted or restarted based on the same logic.

Ah okay, now I understand. This would be and "CT deployment tool" and
should be definitively more stable as the problems I mentioned in my email.
It does not really change dynamically the cluster but rather on the
checkpoints (create, stop CT), sounds quite cool.

>
> What do you think of my logic (if it's clear until now).

The summarize from above seems good to me, if you really plan to
create/start/stop a lot of containers in the cluster try to keep the
evaluation algorithm rather simple so that it runs in O(n) time, else
you could run into performance problems.

> Also, this point is not clear for me (* wait for the cluster to become
> stable (e.g. a few minutes no cluster action), can you explain the reason.

I thought here of (live) migrations, they give the network, and the
nodes some load, whille besides your algorithm there may also run other
- user triggered - actions which also need resources.
Further I want to wait a bit of time to let the cluster stabilize, else
it could trigger unnecessary migrations or an out of control feedback
loop, but this affects you less as you use static resource values (CPU
cores, max ram), as far as I've understood.

best regards,
Thomas

> On 5 April 2016 at 10:42, Thomas Lamprecht <t.lamprecht at proxmox.com> wrote:
>
>> Hi,
>>
>> this idea was proposed quite some time ago and we planned to implement
>> it in the pve-ha-manager stack,
>> as it provides a lot of functionality needed for that.
>>
>> The general idea from our side is:
>> * wait for the cluster to become stable (e.g. a few minutes no cluster
>> action),
>> * evaluate the load
>> * see if there is a configuration which makes the load more equal, here
>> migrate "lighter" VMs first else we may get to big system time delays
>> which are bad for such systems and can cause instability.
>> * if there is any such configuration try to achieve it (migrating one VM
>> at a time).
>> * start at the beginning.
>>
>> There are a few question open, e.g. how to determine load _correctly_ as
>> there are various setups and indicators from memory, cpu, network and
>> IO, which may have different effects on different setups.
>> What happens in edge cases (fencing, ...)
>>
>> Also a static value which can be assigned to VMs would be nice, as just
>> because a VM is lightweight
>>
>> Thus we want to start simple, i.e. use static load balance, then a
>> simple dynamic on (e.g. CPU only) and at best with a simulation which
>> can evaluate how often migration happened and so on (wishlist).
>> And AFAIK, we want to "limit" it to HA Groups, meaning this group should
>> be balanced over the group assigned nodes.
>>
>> The point of this message is to summarize our (or better my) thoughts to
>> that topic and to notify you that there is already something planned and
>> also that there is a Project by us which someone who wants to implement
>> that could make use of, namely the Proxmox VE HA Manager.
>>
>> I appreciate the fact that you want to make something for PVE and wish
>> you the best,
>>  it could be a though worth for you to use some of the HA manager stack
>> using perl would help here, this way it could also land upstream.
>>
>> best regards,
>> Thomas
>>
>>
>> On 04/05/2016 11:04 AM, Mohamed Sadok Ben Jazia wrote:
>>> Hi list,
>>> For my proxmox infrastructure, i set a number of nodes of a cluster.
>>> I'm looking for a load-balancer, to make those tasks:
>>> -Choose the best node for a just created or resized CT/VM.
>>> -Live migration to gain ressources on nodes, or for optimisation.
>>> My idea is to create a dynamic resources scheduler that is integrated
>>> to my server side script to perform this function.
>>>
>>> Here is the ling to the project
>>>
>>> https://github.com/BenJaziaSadok/proxmox-DRS
>>>
>>> Any help with the algorithm or in the development is welcome
>>>
>>> Thank you
>>> _______________________________________________
>>> pve-user mailing list
>>> pve-user at pve.proxmox.com
>>> http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user
>>>
>>
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