kvm啟動報錯與selinux的設置相關解決方法
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1.問題說明
由于kvm所在的機器啟用了SELINUX，后來將之關閉，關閉之后，發現kvm的虛擬機無法啟動，啟動過程中的報錯信息如下：
[root@ESRoller ~]# virsh start zabbix
error: Failed to start domain zabbix
error: unsupported configuration: Unable to find security driver for label selinux
libvirt中的日志也提示報錯：
[root@ESRoller ~]# tail -f /var/log/libvirt/libvirtd.log
2016-06-20 09:54:41.724+0000: 2388: error : qemuRemoveCgroup:754 : internal error Unable to find cgroup for zabbix
2016-06-20 09:54:41.724+0000: 2388: warning : qemuProcessStop:4403 : Failed to remove cgroup for zabbix
2016-06-20 09:54:41.725+0000: 2388: error : qemuAutostartDomain:284 : Failed to autostart VM ‘zabbix‘: unsupported configuration: Unable to find security driver for label selinux
2016-06-20 09:54:41.734+0000: 2388: error : virSecurityManagerGenLabel:376 : unsupported configuration: Unable to find security driver for label selinux
2016-06-20 09:54:41.741+0000: 2388: error : qemuRemoveCgroup:754 : internal error Unable to find cgroup for roller
2016-06-20 09:54:41.741+0000: 2388: warning : qemuProcessStop:4403 : Failed to remove cgroup for roller
2016-06-20 09:54:41.742+0000: 2388: error : qemuAutostartDomain:284 : Failed to autostart VM ‘roller‘: unsupported configuration: Unable to find security driver for label selinux
2016-06-20 09:59:07.548+0000: 2378: error : virSecurityManagerGenLabel:376 : unsupported configuration: Unable to find security driver for label selinux
2016-06-20 09:59:07.561+0000: 2378: error : qemuRemoveCgroup:754 : internal error Unable to find cgroup for zabbix
2016-06-20 09:59:07.561+0000: 2378: warning : qemuProcessStop:4403 : Failed to remove cgroup for zabbix
2.造成原因
由于機器開機狀態時，將SElinux的狀態信息save在虛擬機中，導致SElinux關閉之后，虛擬找不到對應的label，從而導致vm啟動失敗。
3.解決方法
virsh edit domain_name查看虛擬機的配置文件中，是否有selinux標簽的相關設置，如果有，則將其刪除，再啟動vm。如果沒有，則可能已經保存在vm狀態中，將原有的狀態刪除即可(對應路徑/var/lib/libvirt/qemu/save)，如下：
[root@ESRoller ~]# virsh managedsave-remove zabbix
Removed managedsave image for domain zabbix
[root@ESRoller ~]# virsh start zabbix
Domain zabbix started
[root@ESRoller ~]# virsh list
Id Name State
----------------------------------------------------
4 zabbix running
如果配置配置文件中有selinux相關的配置，將其刪除，期配置類似于：
<seclabel type=‘dynamic‘ model=‘selinux‘ relabel=‘yes‘>
<label>system_u:system_r:svirt_t:s0:c625,c859</label>
<imagelabel>system_u:object_r:svirt_image_t:s0:c625,c859</imagelabel>
</seclabel>
