When a user tries to create VM, following sequence of events happen with current CloudStack implementation
(1) User / admin adds a template (which is stored on secondary storage) (2) Template gets downloaded from secondary storage to primary storage (3) New delta disk is created out of downloaded template (4) VM created will be booting from delta disk Requirement: If admin replaces (1) with a new updated template, CS doesn't have a mechanism to create a new mapping between delta disk(3) and updated template. We need to provide a way to create this mapping on restart of user VM. In order to implement the above mentioned requirement, I am planning to modify the API restoreVirtualMachine which creates a new volume for the vm in case its existing volume gets corrupted. Adding the logic to check for the updated template and create a new delta disk from the updated template. Comments/suggestions ? Thanks -Harikrishna
