client-side migration force strategy overrides
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| python-openstackclient (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
Bug Description
There are currently three types of migration force strategies that can be configured in nova: pause (default), post-copy, and auto-converge. They apply to *all* migrations, as the client cannot select its preferred one on a case-by-case basis.
I think it would be preferable to allow clients to override the strategy pre-selected by the cloud administrator, as the "best" strategy depends on the specific workload running on the instance.
Possible use cases:
As a cloud user, I manage various applications, spread over multiple instances. Some of these are highly fault tolerant, others are not highly available at all, some more are sensitive to latency, others to jitter. I therefore understand which force migration strategy works best for which individual instance. Unfortunately, I can only use one: the one the cloud admin has configured for the whole environment.
As a cloud admin, I have to support multiple tenants, with wildly different usage patterns. I want to set a good force migration strategy default to ensure most live migrations succeed and avoid extra support tickets, but while for some tenants auto-converge would be perfect, others would prefer post-copy. I can however only choose one of the three strategy for the whole cloud.
