零、消息队列
1、查看消息队列
rabbitmqctl list_queues
一、nova
0、启动控制节点服务，：
for svc in keystone glance-api glance-registry nova-api nova-objectstore nova-volume nova-scheduler nova-cert nova-novncproxy; do sudo service openstack-$svc start ; sudo chkconfig openstack-$svc on ; done
启动计算节点服务命令：
for svc in compute network metadata-api; do sudo service openstack-nova-$svc start ; sudo chkconfig openstack-nova-$svc on ; done
0、修改配额
tenant_name="admin"
tenant_id="`keystone tenant-list | grep $tenant_name | awk '{print $2}'`"
neutron quota-update --port 2000
cinder quota-update $tenant_id --volumes 500
cinder quota-update $tenant_id --snapshots 500
cinder quota-update $tenant_id --gigabytes 500000
nova quota-update $tenant_id --instances 1000
nova quota-update $tenant_id --cores 2000
nova quota-update $tenant_id --ram 51200000
1、查看openstack集群中的宿主机
[root@node-44 ~]# nova host-list
2、查看虚拟机
[root@node-44 ~]# nova host 或 nova list
3、查看一个虚拟机的详情
[root@node-44 ~]# nova show 089bf9c6-170b-4bf1-9922-494565e33dc0
4、查看镜像列表
[root@control ~]# nova p_w_picpath-list
+--------------------------------------+-------------------+--------+--------+
| ID | Name | Status | Server |
+--------------------------------------+-------------------+--------+--------+
| a760ccc0-782f-4102-bdb8-fd6dc2915ad8 | cirros-0.3.0-i386 | ACTIVE | |
| 6c81f0da-54d0-4f7d-a56d-5c07efa9ed8f | precise-ceph | ACTIVE | |
+--------------------------------------+-------------------+--------+--------+
[root@control ~]#
5、删除镜像
[root@control ~]# nova p_w_picpath-delete cirros-0.3.0-i386-1
6、查看虚拟机模板
[root@control ~]# nova flavor-list
+----+-----------+-----------+------+-----------+------+-------+-------------+-----------+-------------+
| ID | Name | Memory_MB | Disk | Ephemeral | Swap | VCPUs | RXTX_Factor | Is_Public | extra_specs |
+----+-----------+-----------+------+-----------+------+-------+-------------+-----------+-------------+
| 1 | m1.tiny | 512 | 0 | 0 | | 1 | 1.0 | True | {} |
| 2 | m1.small | 2048 | 20 | 0 | | 1 | 1.0 | True | {} |
| 3 | m1.medium | 4096 | 40 | 0 | | 2 | 1.0 | True | {} |
| 4 | m1.large | 8192 | 80 | 0 | | 4 | 1.0 | True | {} |
| 5 | m1.xlarge | 16384 | 160 | 0 | | 8 | 1.0 | True | {} |
+----+-----------+-----------+------+-----------+------+-------+-------------+-----------+-------------+
[root@control ~]#
7、新建一个虚拟机模板
[root@control ~]# nova flavor-create flavor-test 6 512 10 2 --is-public=true
+----+-------------+-----------+------+-----------+------+-------+-------------+-----------+-------------+
| ID | Name | Memory_MB | Disk | Ephemeral | Swap | VCPUs | RXTX_Factor | Is_Public | extra_specs |
+----+-------------+-----------+------+-----------+------+-------+-------------+-----------+-------------+
| 6 | flavor-test | 512 | 10 | 0 | | 2 | 1 | True | {} |
+----+-------------+-----------+------+-----------+------+-------+-------------+-----------+-------------+
[root@control ~]#
9、关机虚拟机
[root@os-node1 ~]# nova stop 9b57d145-d810-4ab2-92e1-11ec44c2cd85
10、开机虚拟机
[root@os-node1 ~]# nova start 9b57d145-d810-4ab2-92e1-11ec44c2cd85
10、查看宿主机的服务状态
[root@os-node1 ~]# nova-manage service list
Binary Host Zone Status State Updated_At
nova-cert os-node1 internal enabled :-) 2014-08-05 00:48:24
nova-consoleauth os-node1 internal enabled :-) 2014-08-05 00:48:33
nova-conductor os-node1 internal enabled :-) 2014-08-05 00:48:29
nova-scheduler os-node1 internal enabled :-) 2014-08-05 00:48:31
nova-compute os-node4 nova enabled XXX 2014-08-04 03:28:00
nova-cells os-node1 internal enabled :-) 2014-08-05 00:48:32
nova-console os-node1 internal enabled :-) 2014-08-05 00:48:34
nova-compute os-node5 nova enabled :-) 2014-08-05 00:48:32
nova-compute os-node6 nova enabled XXX 2014-08-04 04:05:41
[root@os-node1 ~]# nova service-list
+------------------+----------+----------+---------+-------+----------------------------+-----------------+
| Binary | Host | Zone | Status | State | Updated_at | Disabled Reason |
+------------------+----------+----------+---------+-------+----------------------------+-----------------+
| nova-cert | os-node1 | internal | enabled | up | 2014-08-05T01:08:44.000000 | - |
| nova-consoleauth | os-node1 | internal | enabled | up | 2014-08-05T01:08:44.000000 | - |
| nova-conductor | os-node1 | internal | enabled | up | 2014-08-05T01:08:49.000000 | - |
| nova-scheduler | os-node1 | internal | enabled | up | 2014-08-05T01:08:51.000000 | - |
| nova-compute | os-node4 | nova | enabled | down | 2014-08-04T03:28:00.000000 | - |
| nova-cells | os-node1 | internal | enabled | up | 2014-08-05T01:08:52.000000 | - |
| nova-console | os-node1 | internal | enabled | up | 2014-08-05T01:08:44.000000 | - |
| nova-compute | os-node5 | nova | enabled | up | 2014-08-05T01:08:52.000000 | - |
| nova-compute | os-node6 | nova | enabled | down | 2014-08-04T04:05:41.000000 | - |
+------------------+----------+----------+---------+-------+----------------------------+-----------------+
11、创建网段
nova-manage network create --fixed_range_v4=10.0.1.0/24 --vlan=102 --project_id="tenantID"
12、删除虚拟机
nova delete ID
14、迁移一个宿主机上的所有的虚拟机到可用的宿主机上（首先这个被迁移的宿主机的状态是正常的）
[root@LX-OS-node1 ~]# nova host-servers-migrate LX-OS-node11
+--------------------------------------+--------------------+---------------+
| Server UUID | Migration Accepted | Error Message |
+--------------------------------------+--------------------+---------------+
| dcb0a622-839f-4310-b8c7-74bb69dd7d7a | True | |
| 5e748a54-43d6-4bb8-9696-8f13cf45220c | True | |
| 28e1b0f1-1741-4677-bbb6-07f884889cc9 | True | |
+--------------------------------------+--------------------+---------------+
确认迁移
[root@LX-OS-node1 ~]# nova resize-confirm 4bbc5ff6-e9e5-4765-b3c0-60608009153e
[root@LX-OS-node1 ~]# nova resize-confirm 5e748a54-43d6-4bb8-9696-8f13cf45220c
[root@LX-OS-node1 ~]# nova resize-confirm 8b4f2aab-70ca-494d-ad7a-5d67f43ea8f0
15、从一个故障的宿主机迁移上面所有的虚拟机到另外一台宿主机（前者是可用的宿主机，后者是故障的虚拟机，注：只有在用镜像启动建立虚拟机这种情况下可以迁移成功）
[root@LX-OS-node1 ~]# nova host-evacuate --target_host BGW-OS-node11 --on-shared-storage BGW-OS-node12
+--------------------------------------+-------------------+---------------+
| Server UUID | Evacuate Accepted | Error Message |
+--------------------------------------+-------------------+---------------+
| 4bbc5ff6-e9e5-4765-b3c0-60608009153e | True | |
| 5e748a54-43d6-4bb8-9696-8f13cf45220c | True | |
| 8b4f2aab-70ca-494d-ad7a-5d67f43ea8f0 | True | |
+--------------------------------------+-------------------+---------------+
16、把名为aaa的虚拟机迁移到宿主机LX-OS-node12上（次迁移只是迁移虚拟机的内存 cpu 网卡资源，迁移时间很短，网络不会中断，此迁移虚拟机不会重启）
nova live-migration aaa LX-OS-node12
17、普通迁移一台虚拟机（此迁移的目标主机控制器会自动分配,迁移动作执行后需要对此次迁移进行确认，此迁移虚拟机会重启）
nova migrate aaa
nova resize-revert aaa
18、建立一个虚拟机（指定固定IP，此启动方式是：从云硬盘快照启动并创建一个云硬盘，注用这种方式建的当虚拟机被删除是云硬盘不会被删除）
nova boot jiayuan-1 --flavor 9f7a7929-e0f7-4f9b-be48-757aeb2462a7 --snapshot a9c7816b-0046-4aa9-9c82-cb881a969bdd --security-groups default --nic net-id=b7fed806-5a78-4b29-92d1-475567d02643,v4-fixed-ip=10.30.215.201
19、比较完整的建立一个虚拟机(--snapshot 和 --block-device-mapping的不同之处是用后者建的虚拟机删除时可以把云硬盘同时删除，此方式包括了制定固定IP（包括多网卡）、指定宿主机、可以看到进度提示）
nova boot jiayuan-1 --flavor 9f7a7929-e0f7-4f9b-be48-757aeb2462a7 --block-device-mapping vda=a9c7816b-0046-4aa9-9c82-cb881a969bdd:snapshot:300:delete-on-terminate --security-groups default --nic net-id=b7fed806-5a78-4b29-92d1-475567d02643,v4-fixed-ip=10.30.215.230 --nic net-id=3409eea8-9b46-4752-ac63-be0234d18275,v4-fixed-ip=10.30.216.230 --availability-zone nova:LX-OS-node13 --poll
20、批量建立多个虚拟机
nova boot jiayuan-1 --flavor 9f7a7929-e0f7-4f9b-be48-757aeb2462a7 --block-device-mapping vda=a9c7816b-0046-4aa9-9c82-cb881a969bdd:snapshot:300:delete-on-terminate --num-instances 1000 --security-groups default --nic net-id=3409eea8-9b46-4752-ac63-be0234d18275
二、glance
1、压缩一个qcow2格式的镜像
[root@node-44 glance]#qemu-img convert -c ubuntuwcf-10.40.254.64.img -O qcow2 /var/lib/glance/SunDaMing.img
2、查看一个镜像的信息（包括：镜像格式及大小）
[root@node-44 glance]# qemu-img info SunDaMing.img
3、镜像上传
[root@node-44 glance]#glance p_w_picpath-create --is-public true --disk-format qcow2 --container-format bare --name "SunDaMing" < /var/lib/glance/SunDaMing.img
4、使用“glance index”查看映像文件的索引信息。
glance index
ID Name Disk Format Container Format Size
------------------------------------ ------------------------------ -------------------- -------------------- --------------
16bfa875-8e0a-4cc3-8041-e8c64cca9f5e cirros-0.3.0-i386 qcow2 bare 9159168
9f92df26-8fd3-42b9-a00c-b9fb2c73ed21 cirros-0.3.0-x86_64 qcow2 bare 9761280
三、cinder
1、查看所有的云硬盘卷
[root@node-44 ~]# cinder list
2、把volume添加到虚拟机上
( ID是虚拟机的id，后面的1，是volume的ID）添加完后可以通过 nova volume-list查看结果
nova volume-attach 7eb1d4b3-13fa-4e39-be17-3a27eb0db218 1 /dev/vdc
3、删除volume
nova volume-detach VM_ID Volume_ID
4、创建snapshot ( 完成后可以通过 nova p_w_picpath-list 查看）
nova p_w_picpath-create 7eb1d4b3-13fa-4e39-be17-3a27eb0db218 "snapshot 1"
四、neutron
1、查看neutron的配额
[root@os-node1 ~]# neutron quota-show
+------------+-------+
| Field | Value |
+------------+-------+
| floatingip | 50 |
| network | 10 |
| port | 50 |
| router | 10 |
| subnet | 10 |
+------------+-------+
2、修改neutron网络端口的数量
[root@os-node1 ~]# neutron quota-update --port 500 #端口太少的话创建不了太多虚拟机。
+------------+-------+
| Field | Value |
+------------+-------+
| floatingip | 50 |
| network | 10 |
| port | 500 |
| router | 10 |
| subnet | 10 |
+------------+-------+
3、清空openvswitch交换机上的端口
/etc/init.d/neutron-ovs-cleanup start
4、常见一个共享的网络（如果网络是私有属于某个租户：把--shared 去掉，加上--tenant-id TENANT_ID参数）
[root@LX-OS-node1 ~]# neutron net-create vlan215 --shared
+---------------------------+--------------------------------------+
| Field | Value |
+---------------------------+--------------------------------------+
| admin_state_up | True |
| id | c991b42d-982e-4dfc-b7cf-aacf9d00f252 |
| name | vlan215 |
| provider:network_type | vlan |
| provider:physical_network | physnet1 |
| provider:segmentation_id | 215 |
| shared | True |
| status | ACTIVE |
| subnets | |
| tenant_id | e3f13050687a4e3e9967de3b6c22227b |
+---------------------------+--------------------------------------+
[root@LX-OS-node1 ~]# neutron subnet-create vlan215 10.30.215.0/24 --name vlan215 --gateway 10.30.215.254 --allocation-pool start=10.30.215.1,end=10.30.215.200
Created a new subnet:
+------------------+--------------------------------------------------+
| Field | Value |
+------------------+--------------------------------------------------+
| allocation_pools | {"start": "10.30.215.1", "end": "10.30.215.200"} |
| cidr | 10.30.215.0/24 |
| dns_nameservers | |
| enable_dhcp | True |
| gateway_ip | 10.30.215.254 |
| host_routes | |
| id | f8d95fb2-0b6e-4ce4-963d-81a8b4a89f55 |
| ip_version | 4 |
| name | vlan215 |
| network_id | c991b42d-982e-4dfc-b7cf-aacf9d00f252 |
| tenant_id | e3f13050687a4e3e9967de3b6c22227b |
+------------------+--------------------------------------------------+
5、查看neutron-openvswitch-agent运行状态
[root@os-node3 abrt]# service neutron-openvswitch-agent status
neutron-openvswitch-agent (pid 7523) is running...
6、查看openvswitch运行状态
[root@os-node3 abrt]# service openvswitch status
ovsdb-server is running with pid 7477
ovs-vswitchd is running with pid 7486
五、mysql
1、进入数据库
mysql -uroot -p 回车
默认没有密码
2、显示所有的数据库
show databases;
3、进入表
use nova; 进入nova表
4、查看表结构
desC agent_builds; 查看“agent_builds”的表结构
5、查看数据库表信息
mysql> show tables;
6、在数据库migrations表里查找所有东西
mysql> select * from migrations ;
7、在数据库中删除一条信息
mysql> delete * from ipallocationpools where id="041d7993-394b-4ec3-aae3-365aeb5dc10f"；
8、变更云硬盘在数据库volumes表中的信息
mysql> update volumes set host="node-44.domain.tld" where id="8266d5cc-9be5-4c3b-a46e-06aa055c66e1";
9、查看云硬盘几个参数的状态
mysql> select status,attached_host,migration_status,deleted from volumes where id="0d883e29-1bc7-4e54-9eba-1883c4c32313";
10、变更云硬盘在数据库中的存储状态
变更前：
mysql> select status,attached_host,migration_status,deleted from volumes where id="8266d5cc-9be5-4c3b-a46e-06aa055c66e1";
+-----------+---------------+---------------------------------------------+---------+
| status | attached_host | migration_status | deleted |
+-----------+---------------+---------------------------------------------+---------+
| available | NULL | target:10de2dad-21c9-482f-b1c4-5afedef36dde | 0 |
+-----------+---------------+---------------------------------------------+---------+
1 row in set (0.00 sec)
变更后：
mysql> update volumes set migration_status="NULL" where id="8266d5cc-9be5-4c3b-a46e-06aa055c66e1";
mysql> select status,attached_host,migration_status,deleted from volumes where id="8266d5cc-9be5-4c3b-a46e-06aa055c66e1";
+-----------+---------------+------------------+---------+
| status | attached_host | migration_status | deleted |
+-----------+---------------+------------------+---------+
| available | NULL | NULL | 0 |
+-----------+---------------+------------------+---------+
1 row in set (0.00 sec)
11、彻底删除一个有问题的云硬盘
先修改该云硬盘的状态status="deleted"
mysql> update volumes set status="deleted" where id="8266d5cc-9be5-4c3b-a46e-06aa055c66e1";
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
然后修改该云硬盘删除状态
mysql> update volumes set deleted="1" where id="8266d5cc-9be5-4c3b-a46e-06aa055c66e1";
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> update volumes set deleted="1" where Status="deleting";
11、批量删除云硬盘
mysql> update volumes set deleted="1" where Status="deleting";
11、批量删除云硬盘快照
mysql> update snapshots set deleted="1" where Status="error_deleting";
11、彻底删除已删除状态的云硬盘
mysql> delete from volumes where Status="deleted";
ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails (`cinder`.`volume_glance_metadata`, CONSTRAINT `volume_glance_metadata_ibfk_1` FOREIGN KEY (`volume_id`) REFERENCES `volumes` (`id`))
解决上面报错用下面的命令：
mysql> SET FOREIGN_KEY_CHECKS = 0;
Query OK, 0 rows affected (0.00 sec)
再次执行删除就可以删除了
mysql> delete from volumes where Status="deleted";
Query OK, 223 rows affected (0.06 sec)
Query OK, 2 rows affected (0.03 sec)
Rows matched: 2 Changed: 2 Warnings: 0
12、在数据库中查看ip pool
进入neutron表
mysql> select * from ipallocationpools;
13、在数据库中查看已使用的vlan信息
进入neutron表
mysql> select * from ovs_vlan_allocations;
14、变更一个KVM虚拟机的任务状态
变更前的任务状态
mysql> select task_state from instances where hostname="sundaming-10.40.254.62";
+-----------------+
| task_state |
+-----------------+
| p_w_picpath_uploading |
+-----------------+
1 row in set (0.00 sec)
变更状态命令
update instances set task_state="none" where hostname="sundaming-10.40.254.62";
变更后的状态
mysql> select task_state from instances where hostname="sundaming-10.40.254.62";
+------------+
| task_state |
+------------+
| none |
+------------+
1 row in set (0.00 sec)
15、数据库主机用户权限问题
查看mysql中的用户
mysql> use mysql;
mysql> select host, user from user;
+-----------+------+
| host | user |
+-----------+------+
| % | root |
| 127.0.0.1 | root |
| localhost | |
| os-node1 | |
| os-node1 | root |
+-----------+------+
5 rows in set (0.00 sec)
授权一个test用户从任何机器都可以远程登录mysql数据库
mysql> GRANT ALL PRIVILEGES ON *.* TO 'test'@'%' IDENTIFIED BY 'test' WITH GRANT OPTION;
Query OK, 0 rows affected (0.00 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
mysql> select host, user from user;
+-----------+------+
| host | user |
+-----------+------+
| % | root |
| % | test |
| 127.0.0.1 | root |
| localhost | |
| os-node1 | |
| os-node1 | root |
+-----------+------+
6 rows in set (0.00 sec)
在其他的一台机器上测试
[root@os-node11 ~]# mysql -h 10.240.216.1 -utest -p'test'
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 277
Server version: 5.1.71-log Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
16、删除库
mysql> drop database jiayuan123;
17、备份mysql数据库中的keystone库
[root@node-44 ~]# mysqldump -u root -p keystone > /mysql-bak/keystone.sql
18、查看cinder库中使用中的volumes
mysql> use cinder;
mysql> select * from volumes where status ="in-use";
19、查看一个虚拟机的状态
mysql> select vm_state from instances where uuid="5dc5c94b-0752-40a7-9fbf-49d3cf5e4097";
+----------+
| vm_state |
+----------+
| active |
+----------+
20、查看一个虚拟机的运行状态
mysql> select task_state from instances where uuid="9b57d145-d810-4ab2-92e1-11ec44c2cd85";
+------------+
| task_state |
+------------+
| NULL |
+------------+
1 row in set (0.00 sec)
20、修改虚拟机的IP
1）、查找虚拟机的网络端口
mysql> use neutron;
mysql> select * from ports where device_id="3ab73261-82ce-4b9a-9a1c-519624e19dc2";
+----------------------------------+--------------------------------------+------+--------------------------------------+-------------------+----------------+--------+--------------------------------------+--------------+
| tenant_id | id | name | network_id | mac_address | admin_state_up | status | device_id | device_owner |
+----------------------------------+--------------------------------------+------+--------------------------------------+-------------------+----------------+--------+--------------------------------------+--------------+
| 5855410282d54e0cac49f05b40282500 | eccd3444-bb81-4d3b-ae13-58040847da4a | | ed547aa7-af32-495a-8173-5a04be9c37c1 | fa:16:3e:a8:bd:e4 | 1 | DOWN | 3ab73261-82ce-4b9a-9a1c-519624e19dc2 | compute:nova |
+----------------------------------+--------------------------------------+------+--------------------------------------+-------------------+----------------+--------+--------------------------------------+--------------+
1 row in set (0.01 sec)
mysql>
2）、查找虚拟机网络端口的IP地址
mysql> select * from ipallocations where port_id="eccd3444-bb81-4d3b-ae13-58040847da4a";
+--------------------------------------+--------------+--------------------------------------+--------------------------------------+
| port_id | ip_address | subnet_id | network_id |
+--------------------------------------+--------------+--------------------------------------+--------------------------------------+
| eccd3444-bb81-4d3b-ae13-58040847da4a | 10.40.211.28 | e6e73775-ddbc-461a-92ff-b13202c23540 | ed547aa7-af32-495a-8173-5a04be9c37c1 |
+--------------------------------------+--------------+--------------------------------------+--------------------------------------+
1 row in set (0.00 sec)
3）、修改虚拟机的端口的IP地址
mysql> update ipallocations set ip_address="10.40.211.29" where port_id="eccd3444-bb81-4d3b-ae13-58040847da4a";
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from ipallocations where port_id="eccd3444-bb81-4d3b-ae13-58040847da4a";
+--------------------------------------+--------------+--------------------------------------+--------------------------------------+
| port_id | ip_address | subnet_id | network_id |
+--------------------------------------+--------------+--------------------------------------+--------------------------------------+
| eccd3444-bb81-4d3b-ae13-58040847da4a | 10.40.211.29 | e6e73775-ddbc-461a-92ff-b13202c23540 | ed547aa7-af32-495a-8173-5a04be9c37c1 |
+--------------------------------------+--------------+--------------------------------------+--------------------------------------+
1 row in set (0.01 sec)
mysql>
21、在数据库里彻底删除一个虚拟机
mysql> SET FOREIGN_KEY_CHECKS = 0; 修改KEY值，使此库变为可直接删除状态
Query OK, 0 rows affected (0.00 sec)
删除一个虚拟机
mysql> delete from instances where uuid="3ab73261-82ce-4b9a-9a1c-519624e19dc2";
Query OK, 1 row affected (0.03 sec)
批量删除相同状态的虚拟机
mysql> delete from instances where vm_state="active";
Query OK, 22 rows affected (0.01 sec)
mysql> SET FOREIGN_KEY_CHECKS = 1; 删除后，修改KEY值，使此库变为不可直接删除状态
Query OK, 0 rows affected (0.00 sec)
22、导出全部数据库
mysqldump -u root -p -h10.240.216.2 -P3306 --routines --default-character-set=utf8 --lock-all-tables --add-drop-database -A > db.10.240.216.1.sql
23、导入全部数据库
第一种方法直接导入
mysql -uroot -p -h10.240.216.1 -P3306 --default-character-set=utf8 < db.10.240.216.1.sql
第二种方法登录数据库导入:
登录MySQL,执行source命令,后面的文件名要用绝对路径.
......
mysql> source /tmp/db.all.sql;
24、搜索活动的虚拟机的host和uuid的对应关系
[root@os-node1 ~]# mysql -Dnova -e "select host,uuid from instances where vm_state='active'"
+-----------+--------------------------------------+
| host | uuid |
+-----------+--------------------------------------+
| os-node12 | 5209f21b-b81e-4e19-8193-57263dc93dd7 |
| os-node12 | 4f2f3d73-83bf-42ec-81b6-c1739930e520 |
+-----------+--------------------------------------+
25、更新虚拟机实例的任务状态为NULL
有时候一个实例一直卡死在一个任务状态上，不能再对此实例进行任何操作，这是需要在数据库中把这个虚拟机的任务状态改为NULL,修改方法如下：
update instances set task_state=NULL where uuid="5209f21b-b81e-4e19-8193-57263dc93dd7"; 注：NULL值的两边是不用“”括起来的。
26、查看mysql最大连接数（默认是151）
mysql> show variables like 'max_connections';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 20000 |
+-----------------+-------+
1 row in set (0.00 sec)