[node-devel] Support for stateless nodes

[Doron Fediuck]

On 22/02/12 17:33, Doron Fediuck wrote:
> On 22/02/12 16:57, Mike Burns wrote:
>> There has been a lot of interest in being able to run stateless Nodes
>> with ovirt-engine.  ovirt-node has designed a way [1] to achieve this on
>> the node side, but we need input from the engine and vdsm teams to see
>> if we're missing some requirement or if there needs to be changes on the
>> engine/vdsm side to achieve this.
>>
>> As it currently stands, every time you reboot an ovirt-node that is
>> stateless, it would require manually removing the host in engine, then
>> re-registering/approving it again in engine.  
>>
>> Any thoughts, concerns, input on how to solve this?
>>
>> Thanks
>>
>> Mike
>>
>> [1] http://ovirt.org/wiki/Node_Stateless
>>
> 
> Some points need to be considered;
> 
> - Installation issues
> 
> * Just stating the obvious, which is users need
> to remove-add the host on every reboot. This will
> not make this feature a lovable one from user's point of view.
> 
> * During initial boot, vdsm-reg configures the networking
> and creates a management network bridge. This is a very
> delicate process which may fail due to networking issues
> such as resolution, routing, etc. So re-doing this on
> every boot increases the chances of loosing a node due
> to network problems.
> 
> * CA pollution; generating a certificate on each reboot
> for each node will create a huge number of certificates
> in the engine side, which eventually may damage the CA.
> (Unsure if there's a limitation to certificates number,
> but having hundreds of junk cert's can't be good).
> 
> * Today there's a supported flow that for nodes with
> password, the user is allowed to use the "add host"
> scenario. For stateless, it means re-configuring a password
> on every boot...
> 
> - Other issues
> 
> * Local storage; so far we were able to define a local
> storage in ovirt node. Stateless will block this ability.
> 
> * Node upgrade; currently it's possible to upgrade a node
> from the engine. In stateless it will error, since no where
> to d/l the iso file to.
> 
> * Collecting information; core dumps and logging may not
> be available due to lack of space? Or will it cause kernel
> panic if all space is consumed?
> 

One more question / thing to consider;
Currently when you manually install a node,
you need to configure the management-server's address.
Will I need to re-do it on every boot of a stateless node?
-- 

/d

"Air conditioned environment - Do NOT open Windows!"