我基于 php cloudformatino 映像 ami-6fc2f61b 创建了一个新的 ec2 实例，并将我现有的密钥附加到它。安全组允许 ssh 和 http。但是，我无法连接：
$ ssh -v -i /cygdrive/c/data/copy/pk.pem ec2_user@host
OpenSSH_5.9p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Connecting to host [46.xx.xx.xx] port 22.
debug1: Connection established.
debug1: identity file /cygdrive/c/data/copy/pk.pem type -1
debug1: identity file /cygdrive/c/data/copy/pk.pem-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client …