ssh 免密登录配置 （配置后还需要密码输入密码问题解决）

背景

需要搭建jenkins，用来自动部署服务到目标服务器， 所以需要在jenkins所在机器配置免密登录目标服务器

环境

阿里云服务器：服务器A(jenkins所在服务器)，服务器B(部署目标服务器)

步骤

一 服务器A部分

1 登录A,

2 生成秘钥 

1）首先查看.ssh下是否已经有id_rsa和id_rsa.pub文件， 以免被覆盖
2）生成秘钥
   ssh-keygen -t rsa -C "xxx@jenkins"
3）将在.ssh文件夹下生成2个文件  id_rsa, id_rsa.pub， 重命名为  id_rsa_jenkins，id_rsa_jenkins.pub 以免以后冲突

3 配置config

　在~/.ssh 下 创建config文件

Host pre1
    HostName xx.xx.xx.xx

Host pre2
    HostName xx.xx.xx.xx

Host *
    User 登录目标机器的用户
    Port 登录目标机器的端口
    IdentityFile ~/.ssh/id_rsa_jenkins 私钥所在路径

　　由于用户，端口号，秘钥， 都是通用的，所以以通配符来配置，  只有服务器地址不同， 每个目标服务器单独配置

4 拷贝 id_rsa_jenkins.pub 内的内容

二 服务器B部分

1 使用要免密登录的账户登录服务器B

2 在~/.ssh文件夹下 查看是否有 authorized_keys 没有则创建

3 将id_rsa_jenkins.pub的内容， 追加到authorized_keys后面

4 查看 /ect/ssh/sshd_config 

　　需要有如下配置

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile    %h/.ssh/authorized_keys

 

5 切换到root用户 重启 sshd ：   service sshd restart

 

结果

在服务器A ssh pre1  

结果还让输入密码， 一定是我哪里配置的不对， 查找问题

解决问题

开两个窗口， 分别登录服务器A和B

服务器B：

1 登录root用户

2 停止ssh   service ssh stop

3 debug运行ssh  /usr/sbin/sshd -d

服务器A：尝试ssh  ：  ssh -v pre1 查看详情

服务器A日志：

OpenSSH_7.6p1 Ubuntu-4ubuntu0.4, OpenSSL 1.0.2n  7 Dec 2017
debug1: Reading configuration data /var/lib/jenkins/.ssh/config
debug1: /var/lib/jenkins/.ssh/config line 5: Applying options for pre1
debug1: /var/lib/jenkins/.ssh/config line 8: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to **.**.**.** [**.**.**.**] port ****.
debug1: Connection established.
debug1: identity file /var/lib/jenkins/.ssh/id_rsa_jenkins type 0
debug1: key_load_public: No such file or directory
debug1: identity file /var/lib/jenkins/.ssh/id_rsa_jenkins-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.4
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to **.**.**.**:**** as 'username'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:+/jjmuxy3eZ61XEguY2327fz7OfrhIks1edgLK3AnWY
debug1: Host '[**.**.**.**]:****' is known and matches the ECDSA host key.
debug1: Found key in /var/lib/jenkins/.ssh/known_hosts:4
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:XS0Qkck+0F5M0iJdLn3/owfK9QGxPSQxRoYcCGcb9zQ /var/lib/jenkins/.ssh/id_rsa_jenkins
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: password

 发现在登录过程中，尝试证书认证，但是没有认证通过， 改为密码登录， 于是查看服务器B日志，看看因为什么导致证书认证错误

服务器B日志

debug1: sshd version OpenSSH_7.2, OpenSSL 1.0.2g  1 Mar 2016
debug1: private host key #0: ssh-rsa SHA256:FdwiwpgHBW6MTxKJSkVYbtYS/H/kYr+o6JAoFjzOrY8
debug1: private host key #1: ssh-dss SHA256:thpjst+JHWAjnRyEDtOjWeVNO7JFl5K2FETPSLU5hcg
debug1: private host key #2: ecdsa-sha2-nistp256 SHA256:+/jjmuxy3eZ61XEguY2327fz7OfrhIks1edgLK3AnWY
debug1: private host key #3: ssh-ed25519 SHA256:9X0yrjSoRLi/AM/oyozk3Sgd+G0JoDyJbIZFv1rt1Rg
debug1: rexec_argv[0]='/usr/sbin/sshd'
debug1: rexec_argv[1]='-d'
debug1: Set /proc/self/oom_score_adj from 0 to -1000
debug1: Bind to port **** on 0.0.0.0.
Server listening on 0.0.0.0 port ****.
debug1: Server will not fork when running in debugging mode.
debug1: rexec start in 4 out 4 newsock 4 pipe -1 sock 7
debug1: inetd sockets after dupping: 3, 3
Connection from **.**.**.** port **** on **.**.**.** port ****
debug1: Client protocol version 2.0; client software version OpenSSH_7.6p1 Ubuntu-4ubuntu0.4
debug1: match: OpenSSH_7.6p1 Ubuntu-4ubuntu0.4 pat OpenSSH* compat 0x04000000
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.4
debug1: permanently_set_uid: 109/65534 [preauth]
debug1: list_hostkey_types: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
debug1: SSH2_MSG_KEXINIT sent [preauth]
debug1: SSH2_MSG_KEXINIT received [preauth]
debug1: kex: algorithm: curve25519-sha256@libssh.org [preauth]
debug1: kex: host key algorithm: ecdsa-sha2-nistp256 [preauth]
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none [preauth]
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none [preauth]
debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth]
debug1: rekey after 134217728 blocks [preauth]
debug1: SSH2_MSG_NEWKEYS sent [preauth]
debug1: expecting SSH2_MSG_NEWKEYS [preauth]
debug1: rekey after 134217728 blocks [preauth]
debug1: SSH2_MSG_NEWKEYS received [preauth]
debug1: KEX done [preauth]
debug1: userauth-request for user username service ssh-connection method none [preauth]
debug1: attempt 0 failures 0 [preauth]
debug1: PAM: initializing for "username"
debug1: PAM: setting PAM_RHOST to "**.**.**.**"
debug1: PAM: setting PAM_TTY to "ssh"
debug1: userauth-request for user username service ssh-connection method publickey [preauth]
debug1: attempt 1 failures 0 [preauth]
debug1: userauth_pubkey: test whether pkalg/pkblob are acceptable for RSA SHA256:XS0Qkck+0F5M0iJdLn3/owfK9QGxPSQxRoYcCGcb9zQ [preauth]
debug1: temporarily_use_uid: 1000/1000 (e=0/0)
debug1: trying public key file /home/username/.ssh/authorized_keys
debug1: fd 4 clearing O_NONBLOCK
Authentication refused: bad ownership or modes for directory /home/usernamedebug1: restore_uid: 0/0
Failed publickey for username from **.**.**.** port **** ssh2: RSA SHA256:XS0Qkck+0F5M0iJdLn3/owfK9QGxPSQxRoYcCGcb9zQ
Connection closed by **.**.**.** port **** [preauth]
debug1: do_cleanup [preauth]
debug1: monitor_read_log: child log fd closed
debug1: do_cleanup
debug1: PAM: cleanup
debug1: Killing privsep child 17849
debug1: audit_event: unhandled event 12

核心部分， /home/username  用户文件夹权限不对， 修改为700 :chmod 700 /home/username

再来一遍

又出现了

Authentication refused: bad ownership or modes for directory /home/username/.ssh

改为700 

再来一遍 链接成功

最后提醒， 解决完了千万别忘记将服务器B的ssh再启动起来

最后提醒， 解决完了千万别忘记将服务器B的ssh再启动起来

最后提醒， 解决完了千万别忘记将服务器B的ssh再启动起来