这是在AWS上。我尝试使用与另一个Ubuntu实例（＃1）相关联的密钥对启动一个新的Ubuntu实例（＃2）。
AWS实例在启动时与密钥对关联，一旦启动就无法更改。
我可以连接到实例＃1但不能使用相同的ssh命令连接到实例＃2。我已经检查了我的权限，一切似乎都没问题。
密钥在〜/ AMI.pem中。
我的主目录上有chmod 600，〜/ AMI.pem上有chmod 400，所以它只能由我读/写。
实例几乎完全相同，具有相同的安全组和密钥对，相同版本的Ubuntu等。实例＃1安装了一些其他软件包。我确认两者都与称为＆＃34; AMI＆＃34;。
的相同密钥对相关联连接到＃2：
USAU9900:ScrapeEdgar reedn$ ssh -i ~/AMI.pem -v ubuntu@54.67.18.96
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug1: Reading configuration data /Users/reedn/.ssh/config
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: Connecting to 54.67.18.96 [54.67.18.96] port 22.
debug1: Connection established.
debug1: identity file /Users/reedn/AMI.pem type -1
debug1: identity file /Users/reedn/AMI.pem-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.2
debug1: match: OpenSSH_6.2 pat OpenSSH*
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5-etm@openssh.com none
debug1: kex: client->server aes128-ctr hmac-md5-etm@openssh.com none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA 36:69:f6:95:b4:3c:f0:77:02:ab:02:01:af:c7:cc:6a
debug1: Host '54.67.18.96' is known and matches the RSA host key.
debug1: Found key in /Users/reedn/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/reedn/AMI.pem
debug1: read PEM private key done: type RSA
debug1: Authentications that can continue: publickey
debug1: No more authentication methods to try.
*Permission denied (publickey).*
连接到实例＃1：
USAU9900:ScrapeEdgar reedn$ ssh -i ~/AMI.pem -v ubuntu@54.183.77.100
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug1: Reading configuration data /Users/reedn/.ssh/config
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: Connecting to 54.183.77.100 [54.183.77.100] port 22.
debug1: Connection established.
debug1: identity file /Users/reedn/AMI.pem type -1
debug1: identity file /Users/reedn/AMI.pem-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 pat OpenSSH*
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5-etm@openssh.com none
debug1: kex: client->server aes128-ctr hmac-md5-etm@openssh.com none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA a6:53:a0:99:b8:61:ef:fe:05:d3:fe:47:90:ea:de:b6
The authenticity of host '54.183.77.100 (54.183.77.100)' can't be established.
RSA key fingerprint is a6:53:a0:99:b8:61:ef:fe:05:d3:fe:47:90:ea:de:b6.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '54.183.77.100' (RSA) to the list of known hosts.
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/reedn/AMI.pem
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).
Authenticated to 54.183.77.100 ([54.183.77.100]:22)
答案 0 :(得分：0)
首先，您需要确保密钥对已应用于实例＃2。在这个实例的aws控制台中有如下内容：
Key pair name: AMI (should be same as instance #1)
然后尝试以下步骤：
如果此ec2实例不在VPC中，您是否可以停止并启动实例以使用新的公共IP地址刷新并重试？
清除本地计算机中.ssh / known_hosts中的内容，然后重试。
其中一个应该适合你。