On 02/05/2012 02:57 PM, Miki Kenneth wrote: ...
Isn't the VM version derived from the version of the cluster on which it was last edited? For example: you've created a VM on a cluster v3.0. When it is running on a v3.2 cluster, is there any reason to change its version? When it is edited, then perhaps yes - because it may have changed/added properties/features that are only applicable to v3.2. But until then - let it stay in the same version as it was created. (btw, how does this map, if at all, to the '-m' qemu command line switch?) Y.
Currently we do not persist the VM version at all, it is derived from the cluster version the VM belongs to (that's why I suggested to save it as part of the OVF so we can be aware of the VM version when exporting/importing a VM etc.).
The VM does not have to be edited to be influenced by the cluster version. For example if you start a VM on 3.1 cluster you get the stable device address feature with no manual editing.
Livnat
However, I do agree with Yaniv that changing the VM version "under the hood" is a bit problematic. Version is a parameter associated with create/update operation, and less with Run command.
but the engine currently has no logic to detect the need to increase the emulated machine to support feature X. the engine currently does not save this parameter at VM level. it will also need to compare it to the list of supported emulated machines at the cluster, and prevent running the VM if there isn't a match. it also increases the matrix of possible emulated machines being run on different versions of hypervisor to N*cluster_levels, instead of just the number of cluster levels. plus, if a cluster is increased to a new version of hosts which doesn't support an older emulated machine level - user will need to upgrade all VMs one by one? (or will engine block upgrading cluster level if the new cluster level doesn't have an emulated machine in use by one of the virtual machines) it also means engine needs to handle validation logic for this field when exporting/importing (point of this discussion), as well as just moving a VM between clusters. so before introducing all this logic - were issues observed where changing the cluster level (i.e., -M at host level) resulted in problematic changes at guest level worth all of these?