前提
计算节点中一个僵尸计算节点存在，而里面的CPU数目在总物理CPU中，导致认为当前能创建实例。而实际没有这么多资源。
其中node-11为僵尸节点。
原因
删除计算节点不能直接格式化该服务器，否则在控制节点的数据库上会存在该计算节点的数据。
解决办法
参考http://www-01.ibm.com/support/knowledgecenter/SS4KMC_2.3.0/com.ibm.sco.doc_2.3/t_remove_computenode.html
[root@node-9 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 688589
Server version: 5.5.28 MySQL Community Server (GPL), wsrep_23.7.rXXXX
Copyright (c) 2000, 2012, 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> 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
mysql> delete from compute_node_stats where compute_node_id in
-> (select id from compute_nodes
-> where hypervisor_hostname='node-11.domain.tld')
-> delete from compute_nodes where hypervisor_hostname='node-11.domain.tld'
-> delete from services where host='node-11.domain.tld';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'delete from compute_nodes where hypervisor_hostname='node-11.domain.tld'
delete' at line 4
mysql> delete from compute_node_stats where compute_node_id in (select id from compute_nodes where hypervisor_hostname='node-11.domain.tld');
Query OK, 0 rows affected (0.03 sec)
mysql> delete from compute_nodes where hypervisor_hostname='node-11.domain.tld';
Query OK, 1 row affected (0.06 sec)
mysql> delete from services where host='node-11.domain.tld';
Query OK, 2 rows affected (0.01 sec)
mysql>
结果： 