EC2 密钥对信息适用于一台服务器，但不适用于另一台服务器

Question

我有一个已经工作了几年的服务器的密钥对。我今天创建了一个新服务器，并要求它使用相同的密钥对信息。我在控制台中验证了两者都使用相同的密钥对信息。

我可以使用 pem 文件 ssh 进入我的新服务器。所以我知道pem文件没有损坏。但是，我不能ssh 进入我的旧服务器了。

错误是：Permission denied (publickey).

我仍然碰巧对我的旧服务器具有读取权限（我打开了一个已通过 ssh 访问的选项卡），但似乎没有写入权限。

什么可能导致这个问题，我该如何解决？

仅供参考，.ssh/authorized_keys 似乎仍然包含与此 pem 文件关联的公钥。此公钥在两台服务器上是相同的。

更新： 我 99% 确定用户是正确的。我正在使用ubuntu。这是我在之前打开的 ssh 窗口中看到的用户。另外，当我尝试以 root 身份登录时，我收到错误：Please login as the user "ubuntu" rather than the user "root".

更新 #2：

这是带有 -vvv 的 ssh 的输出

$ ssh -i privateKey.pem ubuntu@ec2-XXX-XXX-XXX-XXX.us-west-1.compute.amazonaws.com -vvv
OpenSSH_7.5p1, LibreSSL 2.5.4
debug1: Reading configuration data /Users/USERNAME/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 52: Applying options for *
debug2: resolving "ec2-XXX-XXX-XXX-XXX.us-west-1.compute.amazonaws.com" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to ec2-XXX-XXX-XXX-XXX.us-west-1.compute.amazonaws.com [XXX-XXX-XXX-XXX] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file privateKey.pem type -1
debug1: key_load_public: No such file or directory
debug1: identity file privateKey.pem-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.5
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.8p1 Debian-1ubuntu3
debug1: match: OpenSSH_5.8p1 Debian-1ubuntu3 pat OpenSSH_5* compat 0x0c000000
debug2: fd 5 setting O_NONBLOCK
debug1: Authenticating to ec2-XXX-XXX-XXX-XXX.us-west-1.compute.amazonaws.com:22 as 'ubuntu'
debug3: hostkeys_foreach: reading file "/Users/USERNAME/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /Users/USERNAME/.ssh/known_hosts:3
debug3: load_hostkeys: loaded 1 keys from ec2-XXX-XXX-XXX-XXX.us-west-1.compute.amazonaws.com
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,ssh-dss
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: MACs ctos: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: MACs stoc: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: ecdh-sha2-nistp256
debug1: kex: host key algorithm: ssh-rsa
debug1: kex: server->client cipher: aes128-ctr MAC: umac-64@openssh.com compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: umac-64@openssh.com compression: none
debug3: send packet: type 30
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa SHA256:y6JMkm+4kp5sV9GLZYj0xUKIVSiUXBktG9MxyfnDmxI
debug3: hostkeys_foreach: reading file "/Users/USERNAME/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /Users/USERNAME/.ssh/known_hosts:3
debug3: load_hostkeys: loaded 1 keys from ec2-184-169-151-249.us-west-1.compute.amazonaws.com
debug3: hostkeys_foreach: reading file "/Users/USERNAME/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /Users/USERNAME/.ssh/known_hosts:3
debug3: load_hostkeys: loaded 1 keys from 184.169.151.249
debug1: Host 'ec2-XXX-XXX-XXX-XXX.us-west-1.compute.amazonaws.com' is known and matches the RSA host key.
debug1: Found key in /Users/USERNAME/.ssh/known_hosts:3
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 4294967296 blocks
debug2: key: privateKey.pem (0x0), explicit
debug3: send packet: type 5
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: privateKey.pem
debug3: sign_and_send_pubkey: RSA SHA256:lbgZZp6+4mYEkpoSzvdzajq0K/c5tIm83noZ6ZDL5hE
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey).

Answer 1

我猜你不小心更改了文件/home/ubuntu/.ssh/authorized_keys的权限。我已经重现了错误。根据 AWS，/home/ubuntu/.ssh/authorized_keys 必须仅限于所有者。

如果您已注销，那么您有两种方法可以解决此问题。

方法一：停止实例，点击Actions->Instance Settings->View/Change User Data添加如下用户数据，然后启动实例

Content-Type: multipart/mixed; boundary="//"
MIME-Version: 1.0

--//
Content-Type: text/cloud-config; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="cloud-config.txt"

#cloud-config
cloud_final_modules:
- [scripts-user, always]

--//
Content-Type: text/x-shellscript; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="userdata.txt"

#!/bin/bash
chmod 600 /home/ubuntu/.ssh/authorized_keys
chmod 700 /home/ubuntu/.ssh
chmod 700 /home/ubuntu
--//

方法二：你可以启动一个调试实例。然后停止旧服务器并将旧服务器的根卷挂载到调试实例，并运行以下命令设置正确的权限：

[ubuntu ~]chmod 600 mount_point/home/ubuntu/.ssh/authorized_keys
[ubuntu ~]chmod 700 mount_point/home/ubuntu/.ssh
[ubuntu ~]chmod 700 mount_point/home/ubuntu

它不起作用，您可以按照以下步骤对您的实例进行故障排除：Error: Host key not found, Permission denied (publickey), or Authentication failed, permission denied