Re: [Engine-devel] [node-devel] Support for stateless nodes

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?