Xen managed by libvirt in openstack 遇到问题

Openstack官方描述：

问题

libvirtError: POST operation failed: xend_post: error from xen daemon: (xend.err 'Device /dev/xvdp (51952, tap) is already connected.')

https://github.com/openstack/nova/commit/35c4962c0b97bae5b8751d316d5822fe22c1ab6a

修改后创建虚拟机时仍是err

[root@Dom0 ~(keystone_admin)]$ nova list
+--------------------------------------+---------------+---------+----------+
| ID                                   | Name          | Status  | Networks |
+--------------------------------------+---------------+---------+----------+
| 136c56da-c827-497b-b8b9-bc7b3f0592bf | cirros1       | ERROR   |          |

将p_w_picpath文件改成raw格式，并手工修改libvirt.xml后：

47c3dee4-4a0f-4e43-b3b2-360994c39eb6

instance-00000003

131072

2

xen

/dev/xvda

- qcow2" cache="none"/>

+ raw" cache="none"/>

- sda"/>

+ xvda"/>

- qcow2" cache="none"/>

+ raw" cache="none"/>

- sdb"/>

+ xvdb"/>

[root@Dom0 ~(keystone_admin)]$ nova start cirros1

[root@Dom0 ~(keystone_admin)]$ nova list
+--------------------------------------+---------------+---------+----------+
| ID                                   | Name          | Status  | Networks |
+--------------------------------------+---------------+---------+----------+
| 136c56da-c827-497b-b8b9-bc7b3f0592bf | cirros1       | ACTIVE   |          |

[root@Dom0 instances]# virsh console instance-00000003

  ____               ____  ____
 / __/ __ ____ ____ / __ \/ __/
/ /__ / // __// __// /_/ /\ \
\___//_//_/  /_/   \____/___/
 http://launchpad.net/cirros
login as 'cirros' user. default password: 'cubswin:)'. use 'sudo' for root.
cirros login:

可是，总不能每次都手工修改吧，查阅官方文档后找到了问题的解决办法：

错误原因：

想要nova正确地生成xml配置文件，仅在nova配置文件（/etc/nova/nova.conf）中关于xen的配置使用下面几个参数是不够的，生成的配置文件在p_w_picpath文件格式（默认qcow2而openstack中Xen不支持）和磁盘名称(sdX)上都不对

# COMPUTE
libvirt_type=xen
connection_type=libvirt
compute_driver=libvirt.LibvirtDriver

至少应该这样指定：

# COMPUTE
libvirt_type=xen
connection_type=libvirt
compute_driver=libvirt.LibvirtDriver
libvirt_disk_prefix=xvd
libvirt_p_w_picpaths_type=raw

重启服务：

[root@Dom0 ~(keystone_admin)]$ for svc in api compute network cert console scheduler; do service openstack-nova-$svc restart; done

创建虚拟机实例：

[root@Dom0 ~(keystone_admin)]$ nova boot --flavor 6 --p_w_picpath `nova p_w_picpath-list | grep cirros-0.3.0-x86 | awk '{print $2}'` --key_name testkey --security_group default cirros1

虚拟机正常启动：

[root@Dom0 ~(keystone_admin)]$ nova list
+--------------------------------------+---------+--------+----------------------+
| ID                                   | Name    | Status | Networks             |
+--------------------------------------+---------+--------+----------------------+
| bfdab37b-5419-47c0-90cc-9112000ba4d1 | cirros1 | ACTIVE | private=172.16.200.4 |
+--------------------------------------+---------+--------+----------------------+

ip及key都正常

[root@Dom0 ~(keystone_admin)]$ ssh [email protected]
$ df -h
Filesystem                Size      Used Available Use% Mounted on
/dev                     51.9M         0     51.9M   0% /dev
/dev/xvda1               23.2M     12.9M      9.1M  59% /
tmpfs                    56.1M         0     56.1M   0% /dev/shm
tmpfs                   200.0K     20.0K    180.0K  10% /run
$ whoami
cirros
$

配置文件：

[root@Dom0 instances]# cat instance-00000002/libvirt.xml

  bfdab37b-5419-47c0-90cc-9112000ba4d1
  instance-00000002
  131072
  2
  
    xen
    /dev/xvda