openstack配置完毕，实例也运行正常，怎么登陆进去啊？

我用的镜像就是这个ubuntu官方的precise-server-cloudimg-amd64-disk1.img
然后用 VNC Console只能在火狐下用，说是要用密钥登陆，我在web下载了密钥，然后还是登不进去[root@localhost ~]# nova list
+--------------------------------------+-------------+--------+---------------------------------+
|                  ID                  |     Name    | Status |             Networks            |
+--------------------------------------+-------------+--------+---------------------------------+
| a08cca7a-b52c-4663-827f-07620a4489ae | Ubuntu12.04 | ACTIVE | demonet=10.0.0.2, 172.18.129.97 |