Nova Migration Type

The migration types are:

Non-live migration (sometimes referred to simply as ‘migration’)
The instance is shut down for a period of time to be moved to another hypervisor. In this case, the instance recognizes that it was rebooted.

Live migration (or ‘true live migration’)
Almost no instance downtime. Useful when the instances must be kept running during the migration.
The different types of live migration are:

2-1. Shared storage-based live migration

Both hypervisors have access to shared storage.

2-2. Block live migration

No shared storage is required. Incompatible with read-only devices such as CD-ROMs and Configuration Drive (config_drive).

2-3. Volume-backed live migration

Instances are backed by volumes rather than ephemeral disk, no shared storage is required, and migration is supported (currently only available for libvirt-based hypervisors).

What's this?

nova migrate は Region 間の移動は出来ないので、手動で Nova instance を別の Region へ移動。

Brief summary procedure:

[Region1] Take a Nova instance snapshot, the snapshot is stored in Glance as image.
[Somewhere installed openstack client tool] Download the image from Region1
[Somewhere installed openstack client tool] Upload the image to Region2
[Region2] Create a Nova instance from the snapshot image

[Region1]

Initial state

$ nova list --field name,status,,OS-EXT-STS:vm_state,OS-EXT-AZ:availability_zone
+--------------------------------------+------------+---------+--+----------------------+------------------------------+
| ID                                   | Name       | Status  |  | OS-EXT-STS: Vm State | OS-EXT-AZ: Availability Zone |
+--------------------------------------+------------+---------+--+----------------------+------------------------------+
| 400b58b5-0d50-4163-8a92-27b26f0b7a5b | admin_vm01 | ACTIVE  |  | active               | nova                         |
+--------------------------------------+------------+---------+--+----------------------+------------------------------+

Nova snapshot

Take Nova snapshot

Recommend to stop a instance before take a snapshot.

$ nova image-create --poll admin_vm01 admin_vm01_ss
Server snapshotting... 100% complete
Finished

List Glance images

$ glance image-list --name admin_vm01_ss
+--------------------------------------+---------------+-------------+------------------+------------+--------+
| ID                                   | Name          | Disk Format | Container Format | Size       | Status |
+--------------------------------------+---------------+-------------+------------------+------------+--------+
| 95385cef-879c-4b36-91d7-e96f87c0c8ed | admin_vm01_ss | raw         | bare             | 1073741824 | active |
+--------------------------------------+---------------+-------------+------------------+------------+--------+

$ glance image-show admin_vm01_ss | egrep "Property|instance_uuid"
| Property                              | Value                                |
| Property 'instance_uuid'              | 400b58b5-0d50-4163-8a92-27b26f0b7a5b            |

[Somewhere installed openstack client tool]

Download from Region1

$ glance image-download --file admin_vm01.qcow2 admin_vm01_ss

$ ls -l
-rw-r--r-- 1 root root 1073741824 Feb 10 15:58 admin_vm01.qcow2

Upload to Region2

$ glance image-create --name admin_vm01 \
                      --disk-format qcow2 \
                      --container-format bare \
                      --is-public True \
                      --file admin_vm01.qcow2
+------------------+--------------------------------------+
| Property         | Value                                |
+------------------+--------------------------------------+
| checksum         | 0f4db50348b63ff6f09e6d0ed616c9d2     |
| container_format | bare                                 |
| created_at       | 2015-02-10T07:09:19                  |
| deleted          | False                                |
| deleted_at       | None                                 |
| disk_format      | qcow2                                |
| id               | 6e6eac4e-b151-4ce2-9a8b-970f9ea7962c |
| is_public        | True                                 |
| min_disk         | 0                                    |
| min_ram          | 0                                    |
| name             | admin_vm01                           |
| owner            | 103cfcfb3a094c3382441d21ccff32b3     |
| protected        | False                                |
| size             | 1073741824                           |
| status           | active                               |
| updated_at       | 2015-02-10T07:10:50                  |
| virtual_size     | None                                 |
+------------------+--------------------------------------+

[Region2]

Boot Nova instance from the Glance image uploaded from Region1

AZ

$ nova availability-zone-list | grep -A 5 "^| nova"
| nova                  | available                              |
| |- node-99            |                                        |
| | |- nova-compute     | enabled :-) 2015-02-10T07:18:27.000000 |

Nova boot

$ nova boot --flavor m1.tiny \
            --image admin_vm01 \
            --security-groups default \
            --availability-zone nova \
            admin_vm01
+--------------------------------------+---------------------------------------------------+
| Property                             | Value                                             |
+--------------------------------------+---------------------------------------------------+
| OS-DCF:diskConfig                    | MANUAL                                            |
| OS-EXT-AZ:availability_zone          | nova                                              |
| OS-EXT-SRV-ATTR:host                 | -                                                 |
| OS-EXT-SRV-ATTR:hypervisor_hostname  | -                                                 |
| OS-EXT-SRV-ATTR:instance_name        | instance-0000001a                                 |
| OS-EXT-STS:power_state               | 0                                                 |
| OS-EXT-STS:task_state                | scheduling                                        |
| OS-EXT-STS:vm_state                  | building                                          |
| OS-SRV-USG:launched_at               | -                                                 |
| OS-SRV-USG:terminated_at             | -                                                 |
| accessIPv4                           |                                                   |
| accessIPv6                           |                                                   |
| adminPass                            | zv6GonRfMVfr                                      |
| config_drive                         |                                                   |
| created                              | 2015-02-10T07:19:04Z                              |
| flavor                               | m1.tiny (1)                                       |
| hostId                               |                                                   |
| id                                   | 8c27d436-2049-4f4b-8c23-28dc453e3678              |
| image                                | admin_vm01 (6e6eac4e-b151-4ce2-9a8b-970f9ea7962c) |
| key_name                             | -                                                 |
| metadata                             | {}                                                |
| name                                 | admin_vm01                                        |
| os-extended-volumes:volumes_attached | []                                                |
| progress                             | 0                                                 |
| security_groups                      | default                                           |
| status                               | BUILD                                             |
| tenant_id                            | 103cfcfb3a094c3382441d21ccff32b3                  |
| updated                              | 2015-02-10T07:19:04Z                              |
| user_id                              | 451fd821ff05490984234a72b585a7d9                  |
+--------------------------------------+---------------------------------------------------+

Check

$ nova list
+--------------------------------------+------------+--------+------------+-------------+-------------------------+
| ID                                   | Name       | Status | Task State | Power State | Networks                |
+--------------------------------------+------------+--------+------------+-------------+-------------------------+
| 8c27d436-2049-4f4b-8c23-28dc453e3678 | admin_vm01 | ACTIVE | -          | Running     | external=10.10.10.10    |
+--------------------------------------+------------+--------+------------+-------------+-------------------------+

$ nova show admin_vm01 | egrep "Property|hypervisor| id |image"
| Property                             | Value                                                    |
| OS-EXT-SRV-ATTR:hypervisor_hostname  | node-99                                                  |
| id                                   | 8c27d436-2049-4f4b-8c23-28dc453e3678                     |
| image                                | admin_vm01 (6e6eac4e-b151-4ce2-9a8b-970f9ea7962c)        |

Environment

Openstack : Juno
Ceph : Firefly

Reference

Nova Migration (non live migration) to Different Hypervisor
Nova Migration (non live migration) to Different Hypervisor between AZ
Nova Migration (true live migration) to Different Hypervisor
Nova Migration (true live migration) to Different Hypervisor between AZ
Nova Migration (Manually) between AZ
Nova Migration (Manually) between Region
Nova Migration (true live migration) to Different Hypervisor - Volume-backend live migration (instance)
Nova Migration (true live migration) to Different Hypervisor - Volume-backend live migration (instance) between AZ