废话开头：
之前参考这位同学的博客http://www.cnblogs.com/awy-blog/p/3447176.html，同时综合OpenStack的ubuntu的官方安装文档，在修改了一些小错误之后，成功地用三台普通的物理PC机搭了一个OpenStack的环境，各项服务、功能都测试了一遍，感觉还可以。不过后来，由于其中的一台物理机被别人拿走之后，于是乎没继续使用测试了，转而去研究代码了。
后来，由于某种需求，又要开重新搭建这个环境。没有够多的物理机，于是乎开始使用楼下的一台刀片服务器来完了，12核24线程、40多G的大内存，4块500G的硬盘，够给力了，跑三个虚拟机来搭OpenStack的环境也绰绰有余了。但是，搭完之后，问题就来了，发现无法向虚机注入密钥，也就是用ssh密钥登录虚机了。这对那些必须需要使用密钥登录的镜像来说还是有很大的不便。
下面开始步入正题：
虚机起来后，查看日志/var/log/nova/nova-api.log ：
2014-03-08 15:36:02.347 16855 INFO nova.metadata.wsgi.server [-] (16855) accepted ('192.168.122.3', 55466)
2014-03-08 15:36:02.349 16855 WARNING nova.api.metadata.handler [-] X-Instance-ID-Signature: ed0c9bbac98384bb1d4f2b0923e33488af7ac2fbbaac0aef6fe2b80257cded79 does not match the expected value: 93008c9f8f5a8ddda5a9fd48fb29b53db2e2ef1c76684ef4f6e5152fc951885d for id: c011b486-3cfd-4e33-8fb8-526abe1e51fb. Request From: 10.50.50.2
2014-03-08 15:36:02.350 16855 INFO nova.api.ec2 [-] 0.1089s 192.168.122.3 GET /2009-04-04/meta-data/public-hostname None:None 403 [Python-httplib2/0.7.2 (gzip)] text/plain text/plain
2014-03-08 15:36:02.350 16855 INFO nova.metadata.wsgi.server [-] 10.50.50.2,192.168.122.3 "GET /2009-04-04/meta-data/public-hostname HTTP/1.1" status: 403len: 176 time: 0.0018518
2014-03-08 15:36:02.865 16855 WARNING nova.api.metadata.handler [-] X-Instance-ID-Signature: ed0c9bbac98384bb1d4f2b0923e33488af7ac2fbbaac0aef6fe2b80257cded79 does not match the expected value: 93008c9f8f5a8ddda5a9fd48fb29b53db2e2ef1c76684ef4f6e5152fc951885d for id: c011b486-3cfd-4e33-8fb8-526abe1e51fb. Request From: 10.50.50.2
2014-03-08 15:36:02.867 16855 INFO nova.api.ec2 [-] 0.1279s 192.168.122.3 GET /2009-04-04/meta-data/placement/availability-zone None:None 403 [Python-httplib2/0.7.2 (gzip)] text/plain text/plain
2014-03-08 15:36:02.868 16855 INFO nova.metadata.wsgi.server [-] 10.50.50.2,192.168.122.3 "GET /2009-04-04/meta-data/placement/availability-zone HTTP/1.1" status: 403len: 176 time: 0.0024281在dashboard的界面里面，查看虚机的日志中提示错误：
checking http://169.254.169.254/2009-04-04/instance-id
failed 1/20: up 10.44. iid had '<html>
<head>
<title>500 Internal Server Error</title>
</head>
<body>
<h1>500 Internal Server Error</h1>
An unknown error has occurred. Please try your request again.<br /><br />
而当我登录虚拟，查看里面的~/.ssh/authorized_keys里面内容不是要注入的公钥，正是上面出错的html页面代码！
在虚机中运行curl检测如下：
$ curl -I http://169.254.169.254/2009-04-04/meta-data/instance-id
HTTP/1.1 500 Internal Server Error
Content-Type: text/html; charset=UTF-8
Content-Length: 0
Date: Sat, 08 Mar 2014 09:45:57 GMT
if resp.status == 200:
LOG.debug(str(resp))
return content
elif resp.status == 403:
msg = _(
'The remote metadata server responded with Forbidden. This'
'response usually occurs when shared secrets do not match.'
)
LOG.warn(msg)
return webob.exc.HTTPForbidden()
elif resp.status == 404:
return webob.exc.HTTPNotFound()
elif resp.status == 409:
return webob.exc.HTTPConflict()
elif resp.status == 500:
msg = _(
'Remote metadata server experienced an internal server error.'
)
LOG.warn(msg)
return webob.exc.HTTPInternalServerError(explanation=unicode(msg))
else:
raise Exception(_('Unexpected response code: %s') % resp.status)
# shared secret to prevent spoofing. You may select any string for a secret,
# but it must match here and in the configuration used by the Nova Metadata
# Server. NOTE: Nova uses a different key: neutron_metadata_proxy_shared_secret
【OpenStack】metadata在OpenStack中的使用：