SSH 配置公钥登录无效仍需输入密码[一个微妙的问题点]

今晚在折腾集群管理问题，其中最重要的一个问题就是需要各节点的免密码登录，那就必须在各个机器上配置公钥。

配置公钥

ssh-keygen

将公钥复制到被控制机器中，实现免密码登录

ssh-copy-id -i ~/.ssh/id_rsa.pub -p 22 root@目标ip

正常情况下执行这两步就已经可以了，但是我遇到了一个问题，就是有的机器没有问题，可以正常直接登录，但部分机器，永远都是公钥通不过，需要密码登录。

无法公钥登录的解决

登陆时执行如下命令查看详细日志

ssh x.x.x.x -vvv

 debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available (default cache: KEYRING:persistent:0)

debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available (default cache: KEYRING:persistent:0)

debug2: we did not send a packet, disable method
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /root/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Trying private key: /root/.ssh/id_dsa
debug3: no such identity: /root/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /root/.ssh/id_ecdsa
debug3: no such identity: /root/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /root/.ssh/id_ed25519
debug3: no such identity: /root/.ssh/id_ed25519: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password

这里大家对比下正常登录的日志是可以看到区别的，但是也看不出问题所在。

网上找了几个小时的资料，试了各种方法，比如：

sshd_config配置

HostKey /etc/ssh/ssh_host_rsa_key

RSAAuthentication yes

PubkeyAuthentication yes

AuthorizedKeysFile      .ssh/authorized_keys

selinux配置
目录及文件权限调整
文件格式问题

几乎所有问题都排查了，仍然不行，但是在查看日志： /var/log/secure 还是可以看出端倪

 
Feb 8 00:01:42 izwz90g1ws14xwy7e4fqe3z sshd[7454]: Authentication refused: bad ownership or modes for directory /root
Feb 8 00:35:48 izwz90g1ws14xwy7e4fqe3z sshd[15171]: Authentication refused: bad ownership or modes for directory /root
Feb 8 00:38:22 izwz90g1ws14xwy7e4fqe3z sshd[18337]: Authentication refused: bad ownership or modes for file /root/.ssh/authorized_keys
Feb 8 00:38:39 izwz90g1ws14xwy7e4fqe3z sshd[18337]: Connection closed by 120.77.212.168 [preauth]
Feb 8 00:38:41 izwz90g1ws14xwy7e4fqe3z sshd[18742]: Authentication refused: bad ownership or modes for directory /root

其实这里相关的资料网上也找了不少，也都各种尝试给权限：
chmod g-w /home/your_user # 或　chmod 0755 /home/your_user 
chmod 700 /home/your_user/.ssh（~/.ssh）
chmod 600 /home/your_user/.ssh/authorized_keys（~/.ssh/authorized_keys）

但是发现并没有什么用，确认了.ssh 目录和 authorized_keys文件的权限都没有问题，仍然不奏效。

因为我是root用户家目录就是/root，突发奇想看看/root根目录的权限，发现是737，而正常可以连接的机器/root权限没这么高，是550

无法登陆的机器：