Openstack上虚拟机迁移
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1、迁移虚拟机可以进行冷迁移和热迁移
# 冷迁移
关闭电源的虚拟机进行迁移。通过冷迁移，可以选择将关联的磁盘从一个数据存储移动到另一个数据存储。
好处：虚拟机不需要位于共享存储器上，数据丢失率小。
缺点：需要关闭电源，业务中断。
# 热迁移
即虚拟机保存/恢复，通常是将整个虚拟机的运行状态完整保存下来，同时可以快速的恢复到原有硬件平台甚至是不同硬件平台上。恢复以后，虚拟机仍旧平滑运行，用户不会察觉到任何差异。
好处：软件和硬件系统的维护升级，不会影响用户的关键服务，提高了服务的高可用性和 用户的满意度。
缺点：过程不可中断，操作复杂。需要共享存储
冷迁移的操作方法：（采用的是第三种）
【1】dashbord页面进行操作
选取相应实例，服务器关机、选择进行迁移（无法确认迁移主机)
【2】命令行操作
https://docs.openstack.org/nova/queens/admin/migration.html
【3】主机手动拷贝磁盘文件操作
1、关闭虚拟机
2、拷贝相关虚拟机相关的磁盘文件到目标宿主机上，并修改相应的权限
3、修改数据库相关的配置，袖改host、node相关记录的主机
update instances set host=new_host, node=new_host where uuid=xxxxx*xxxx;
4、旧磁盘保存三天，无问题进行删除
OpenStack手动迁移虚拟机
基于OpenStack平台搭建完成后
迁移的步骤：
1、将关于虚拟机的数据移到目标主机（移动之前需要关闭虚拟机）
在OpenStack里云主机的数据存放目录是/var/lib/nova/instances/
2、修改数据库文件
在nova数据库的instances 表里有记录虚拟机的宿主机的名字，所以需要进入数据库修改该字段为controller
实战;
一、首先创建一个虚拟机
在管理员的虚拟机管理器界面可以看到虚拟机的主机是compute（我们要把虚拟机从compute节点迁移到controller节点）
点击云主机的名字可以进入查看云主机的详细信息，可以看到一开始他的主机是compute
二、开始把数据迁移到controller
云主机关上
在/var/lib/nova/instances/里，存放着云主机的数据，下面的b5f1929f-e51c-443d-be02-1854e26443cb目录就是我们测试的云主机的id
compute节点：
[root@compute instances]# cd /var/lib/nova/instances/
[root@compute instances]# ll
total 4
drwxr-xr-x. 2 nova nova 69 Jul 16 03:30 b5f1929f-e51c-443d-be02-1854e26443cb
drwxr-xr-x. 2 nova nova 53 Jul 11 18:43 _base
-rw-r--r--. 1 nova nova 30 Jul 16 02:50 compute_nodes
drwxr-xr-x. 2 nova nova 91 Jul 11 18:50 locks
把它复制到controller节点，把本主机的删除
[root@compute instances]# scp -r b5f1929f-e51c-443d-be02-1854e26443cb root@10.30.59.218:/var/lib/nova/instances
root@10.30.59.218's password:
console.log 100% 37KB 37.2KB/s 00:00
disk.info 100% 79 0.1KB/s 00:00
disk 100% 14MB 14.0MB/s 00:01
libvirt.xml
[root@compute instances]# rm -rf b5f1929f-e51c-443d-be02-1854e26443cb
controller节点：
把它的用户和用户组修改成nova
[root@controller instances]# ll
total 0
drwxr-xr-x. 2 root root 69 Jul 16 03:35 b5f1929f-e51c-443d-be02-1854e26443cb
[root@controller instances]# chown -R nova:nova b5f1929f-e51c-443d-be02-1854e26443cb/
[root@controller instances]# ll
total 0
drwxr-xr-x. 2 nova nova 69 Jul 16 03:35 b5f1929f-e51c-443d-be02-1854e26443cb
然后修改数据库文件
[root@controller instances]# mysql -uroot -p000000
Welcome to the MariaDB monitor. Commands end with ; or \\g.
Your MariaDB connection id is 2151
Server version: 10.1.17-MariaDB MariaDB Server
Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\\h' for help. Type '\\c' to clear the current input statement.
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| cinder |
| glance |
| information_schema |
| keystone |
| mysql |
| neutron |
| nova |
| nova_api |
| performance_schema |
+--------------------+
9 rows in set (0.00 sec)
MariaDB [(none)]> use nova
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
MariaDB [nova]> show tables;
+--------------------------------------------+
| Tables_in_nova |
+--------------------------------------------+
| agent_builds |
| aggregate_hosts |
| aggregate_metadata |
| aggregates |
| allocations |
| block_device_mapping |
| bw_usage_cache |
| cells |
| certificates |
| compute_nodes |
| console_pools |
| consoles |
| dns_domains |
| fixed_ips |
| floating_ips |
| instance_actions |
| instance_actions_events |
| instance_extra |
| instance_faults |
| instance_group_member |
| instance_group_policy |
| instance_groups |
| instance_id_mappings |
| instance_info_caches |
| instance_metadata |
| instance_system_metadata |
| instance_type_extra_specs |
| instance_type_projects |
| instance_types |
| instances |
| inventories |
| key_pairs |
| migrate_version |
| migrations |
| networks |
| pci_devices |
| project_user_quotas |
| provider_fw_rules |
| quota_classes |
| quota_usages |
| quotas |
| reservations |
| resource_provider_aggregates |
| resource_providers |
| s3_images |
| security_group_default_rules |
| security_group_instance_association |
| security_group_rules |
| security_groups |
| services |
| shadow_agent_builds |
| shadow_aggregate_hosts |
| shadow_aggregate_metadata |
| shadow_aggregates |
| shadow_block_device_mapping |
| shadow_bw_usage_cache |
| shadow_cells |
| shadow_certificates |
| shadow_compute_nodes |
| shadow_console_pools |
| shadow_consoles |
| shadow_dns_domains |
| shadow_fixed_ips |
| shadow_floating_ips |
| shadow_instance_actions |
| shadow_instance_actions_events |
| shadow_instance_extra |
| shadow_instance_faults |
| shadow_instance_group_member |
| shadow_instance_group_policy |
| shadow_instance_groups |
| shadow_instance_id_mappings |
| shadow_instance_info_caches |
| shadow_instance_metadata |
| shadow_instance_system_metadata |
| shadow_instance_type_extra_specs |
| shadow_instance_type_projects |
| shadow_instance_types |
| shadow_instances |
| shadow_key_pairs |
| shadow_migrate_version |
| shadow_migrations |
| shadow_networks |
| shadow_pci_devices |
| shadow_project_user_quotas |
| shadow_provider_fw_rules |
| shadow_quota_classes |
| shadow_quota_usages |
| shadow_quotas |
| shadow_reservations |
| shadow_s3_images |
| shadow_security_group_default_rules |
| shadow_security_group_instance_association |
| shadow_security_group_rules |
| shadow_security_groups |
| shadow_services |
| shadow_snapshot_id_mappings |
| shadow_snapshots |
| shadow_task_log |
| shadow_virtual_interfaces |
| shadow_volume_id_mappings |
| shadow_volume_usage_cache |
| snapshot_id_mappings |
| snapshots |
| tags |
| task_log |
| virtual_interfaces |
| volume_id_mappings |
| volume_usage_cache |
+--------------------------------------------+
109 rows in set (0.00 sec)
MariaDB [nova]> select host,node,uuid from instances;
+------------+------------+--------------------------------------+
| host | node | uuid |
+------------+------------+--------------------------------------+
| compute | compute | 52aae669-86a9-4122-a1e4-dee2c4841456 |
| controller | controller | e6c4070f-3dd9-475c-9676-3c5108161fb9 |
| compute | compute | b5f1929f-e51c-443d-be02-1854e26443cb | ## 这时候看它的主机是compute
+------------+------------+--------------------------------------+
3 rows in set (0.00 sec)
MariaDB [nova]> update instances set host='controller',node='controller' where uuid='b5f1929f-e51c-443d-be02-1854e26443cb';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
MariaDB [nova]> select host,node,uuid from instances;
+------------+------------+--------------------------------------+
| host | node | uuid |
+------------+------------+--------------------------------------+
| compute | compute | 52aae669-86a9-4122-a1e4-dee2c4841456 |
| controller | controller | e6c4070f-3dd9-475c-9676-3c5108161fb9 |
| controller | controller | b5f1929f-e51c-443d-be02-1854e26443cb | ## 修改完成后
+------------+------------+--------------------------------------+
3 rows in set (0.00 sec)
MariaDB [nova]> exit
重启nova服务
[root@controller instances]# systemctl restart openstack-nova-compute
开启虚拟机
[root@controller instances]# nova start b5f1929f-e51c-443d-be02-1854e26443cb
Request to start server b5f1929f-e51c-443d-be02-1854e26443cb has been accepted.
[root@controller instances]# nova show b5f1929f-e51c-443d-be02-1854e26443cb
+--------------------------------------+----------------------------------------------------------+
| Property | Value |
+--------------------------------------+----------------------------------------------------------+
| OS-DCF:diskConfig | AUTO |
| OS-EXT-AZ:availability_zone | nova |
| OS-EXT-SRV-ATTR:host | controller |
| OS-EXT-SRV-ATTR:hostname | test |
| OS-EXT-SRV-ATTR:hypervisor_hostname | controller |
| OS-EXT-SRV-ATTR:instance_name | instance-00000003 |
| OS-EXT-SRV-ATTR:kernel_id | |
| OS-EXT-SRV-ATTR:launch_index | 0 |
| OS-EXT-SRV-ATTR:ramdisk_id | |
| OS-EXT-SRV-ATTR:reservation_id | r-vmbh21l4 |
| OS-EXT-SRV-ATTR:root_device_name | /dev/vda |
| OS-EXT-SRV-ATTR:user_data | - |
| OS-EXT-STS:power_state | 4 |
| OS-EXT-STS:task_state | powering-on |
| OS-EXT-STS:vm_state | stopped |
| OS-SRV-USG:launched_at | 2021-07-15T19:30:25.000000 |
| OS-SRV-USG:terminated_at | - |
| accessIPv4 | |
| accessIPv6 | |
| config_drive | |
| created | 2021-07-15T19:30:19Z |
| description | test |
| flavor | m1.small (2) |
| hostId | b4d8e7c2f999c39aa116d311d30396839ddd46175cb62be11c48faf5 |
| host_status | |
| id | b5f1929f-e51c-443d-be02-1854e26443cb |
| image | centos7 (d108a3da-a0ed-48dd-9e1f-ec40b92c06b2) |
| int-net network | 10.10.10.103 |
| key_name | - |
| locked | False |
| metadata | {} |
| name | test |
| os-extended-volumes:volumes_attached | [] |
| security_groups | default |
| status | SHUTOFF |
| tenant_id | f9d44679d8da4276b113fe99fe3b26c6 |
| updated | 2021-07-15T19:40:01Z |
| user_id | 1a81b852a6104c8d874d700cbfb1c705 |
+--------------------------------------+----------------------------------------------------------+
[root@controller instances]#
在图形界面里查看
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