2014-04-04 12:46 GMT+08:00 Jay Pipes <[email protected]>: > On Fri, 2014-04-04 at 11:08 +0800, Jay Lau wrote: > > Thanks Jay and Chris for the comments! > > > > @Jay Pipes, I think that we still need to enable "one nova compute > > live migration" as one nova compute can manage multiple clusters and > > VMs can be migrated between those clusters managed by one nova > > compute. > > Why, though? That is what I am asking... seems to me like this is an > anti-feature. What benefit does the user get from moving an instance > from one VCenter cluster to another VCenter cluster if the two clusters > are on the same physical machine? > @Jay Pipes, for VMWare, one physical machine (ESX server) can only belong to one VCenter cluster, so we may have following scenarios. DC | |---Cluster1 | | | |---host1 | |---Cluser2 | |---host2
Then when using VCDriver, I can use one nova compute manage both Cluster1 and Cluster2, this caused me cannot migrate VM from host2 to host1 ;-( The bp was introduced by https://blueprints.launchpad.net/nova/+spec/multiple-clusters-managed-by-one-service > > Secondly, why is it that a single nova-compute manages multiple VCenter > clusters? This seems like a hack to me... perhaps someone who wrote the > code for this or knows the decision behind it could chime in here? > > > For cell, IMHO, each "cell" can be treated as a small "cloud" but not > > a "compute", each "cell cloud" should be able to handle VM operations > > in the small cloud itself. Please correct me if I am wrong. > > Yes, I agree with you that a cell is not a compute. Not sure if I said > otherwise in my previous response. Sorry if it was confusing! :) > > Best, > -jay > > > @Chris, "OS-EXT-SRV-ATTR:host" is the host where nova compute is > > running and "OS-EXT-SRV-ATTR:hypervisor_hostname" is the hypervisor > > host where the VM is running. Live migration is now using "host" for > > live migration. What I want to do is enable migration with one "host" > > and the "host" managing multiple "hyperviosrs". > > > > > > I'm planning to draft a bp for review which depend on > > https://blueprints.launchpad.net/nova/+spec/vmware-auto-inventory > > > > > > Thanks! > > > > > > > > 2014-04-04 8:03 GMT+08:00 Chris Friesen <[email protected]>: > > On 04/03/2014 05:48 PM, Jay Pipes wrote: > > On Mon, 2014-03-31 at 17:11 +0800, Jay Lau wrote: > > Hi, > > > > Currently with VMWare VCDriver, one nova > > compute can manage multiple > > clusters/RPs, this caused cluster admin cannot > > do live migration > > between clusters/PRs if those clusters/PRs > > managed by one nova compute > > as the current live migration logic request at > > least two nova > > computes. > > > > > > A bug [1] was also filed to trace VMWare live > > migration issue. > > > > I'm now trying the following solution to see > > if it is acceptable for a > > fix, the fix wants enable live migration with > > one nova compute: > > 1) When live migration check if host are same, > > check both host and > > node for the VM instance. > > 2) When nova scheduler select destination for > > live migration, the live > > migration task should put (host, node) to > > attempted hosts. > > 3) Nova scheduler needs to be enhanced to > > support ignored_nodes. > > 4) nova compute need to be enhanced to check > > host and node when doing > > live migration. > > > > What precisely is the point of "live migrating" an > > instance to the exact > > same host as it is already on? The failure domain is > > the host, so moving > > the instance from one "cluster" to another, but on the > > same host is kind > > of a silly use case IMO. > > > > > > Here is where precise definitions of "compute node", > > "OS-EXT-SRV-ATTR:host", and > > "OS-EXT-SRV-ATTR:hypervisor_hostname", and "host" as > > understood by novaclient would be nice. > > > > Currently the "nova live-migration" command takes a "host" > > argument. It's not clear which of the above this corresponds > > to. > > > > My understanding is that one nova-compute process can manage > > multiple VMWare physical hosts. So it could make sense to > > support live migration between separate VMWare hosts even if > > they're managed by a single nova-compute process. > > > > Chris > > > > > > _______________________________________________ > > OpenStack-dev mailing list > > [email protected] > > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > > > > > > > -- > > Thanks, > > > > > > Jay > > > > _______________________________________________ > > OpenStack-dev mailing list > > [email protected] > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > _______________________________________________ > OpenStack-dev mailing list > [email protected] > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > -- Thanks, Jay
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