Changes:
To make sure migration does not attempt to pick a host that has running VMs more than the max guest VM's limit:
- Changed manual migration to call host allocators to return a list of hosts suitable for migration. Host allocators check for the max guest VM limit.
- Earlier we returned hosts with enough capacity but now Host Allocators make other checks along with capacity. So the list of hosts returned are hosts that have enough capacity AND satisfy all other conditions like host tags, max guests limit etc. Or in other words Allocators dont return the hosts that dont satisfy all conditions even if they have capacity.
-Therefore, now we mark the list of hosts returned for manual migration as 'suitable' hosts instead of 'hasenoughCapacity' in the HostResponse.
- HA migration already calls allocators, so no change is needed there.
Changes:
- Adding a new table 'hypervisor_capabilities' that will record capabilities for each hypervisor version. Added db schema changes for this.
- Currently a few capabilities have been added, namely, 'max_guests_limit' and 'security_group_enabled'
- Added a new column 'hypervisor_version' to host table. StartupRouting command now takes in this parameter. It should be set when a host connects.
- If a host's hypervisor version is not present, we find all the capabilities rows for that hypervisor type and use the first record.
- 'max_guests_limit' is the maximum number of running guest Vms that a host can have for the given hypervisor.
- Host Allocators use this limit and skip a host if the number of running VMs on that host exceeds this limit.
frank
prachi