8:48 p.m.
On 10/20/2014 12:50 AM, simonjin wrote:
Hi all,
I'm presenting here my proposal for the feature "Guest migration" which
is expected to be implemented for Kimchi 1.4.
Description
Migrate guest vm within peer/host discovered by Kimchi peers using
openSLP.
In the first stage 1, only do migration will be supported,
in stage2, migrateCancel and migrateMonitor will be supported.
*Migration Mode: *
1. Support libvirt tunnelled transport managed by direct migration.
2. Only support Live migration mode.
3. Only support migration over TCP
*Migration Capability Check*
- Source libvirtd/client should be able to connect destination libvirtd.
- CPU architectures compare(X86 vs PPC).
- No PCI device passthrough.
- In a shared storage pool and the pool can be access/write by
destination.
REST API
Only one new REST command will be added in stage 1.
Syntax
POST /vms//<vm-name>//migrate
You will have a data object informing the destination host
POST /vms/<vm-name>/migrate {host: ...}
Parameters:
in config.py.in:
('migration_destination_timeout', '21600',
'Maximum time the destination waits for the migration to
finish.
21600 should be enough since all the peers will be in the
same LAN'),
('migration_max_bandwidth', 'unlimited',
'default in libvirt is unlimited'),
('migration_downtime', '500',
'Maxmium allowed downtime for live migration in milliseconds '
'(anything below 100ms is ignored) if you do not care about '
'liveness of migration, set to a very high value, such as '
'600000.'),
I don't think we need to allow user edits those values so there is no
need to add them to config.py.in
Return:
An asynchronous Task with "target_uri" containing
"/vms/</new-vm-name/>".
As expected with any Task, the cloning process can be tracked by
checking the corresponding task's status.
*Do_migration step:*
- migration source check .
What kind of verification will be done?
Storage pool and network? Guest permission settings?
- connect migration destination, guest vm config/params transfer and
setup.
How will it be done?
From libvirt doc, I can see different types of migration, which one is
the best solution for Kimchi?
For reference: http://libvirt.org/migration.html
- migration source prepare.
- do actually migration.
Does libvirt python API have native support for that?
- recover if failed.
Probably, on fail, some leftovers will be on destination server. How
will you do the clean up?
Will it be a communication between the Kimchi servers? What about if the
destination server does not have a Kimchi setup?
- do finish if migration successful.
Comments are welcome!
--
Yun Tong Jin, Simon
Linux Technology Center, Open Virtualization project
IBM Systems & Technology Group
jinyt(a)cn.ibm.com, Phone: 824549654