問題描述：

上周給公司搭建大數據平臺，選取三臺機器，安裝配置一切順利。后來發現/home目錄的掛載盤容量不夠用，所以就擴容了，在擴容之前將/home/hadoop文件夾復制到其他地方，擴容后再復制回來，現在問題來了，hadoop文件夾遷移回來后，發現免匙SSH無用了。

問題排查：

1.檢測權限

chmod 600 ~/.ssh/authorized_keys chmod 700 ~/.ssh/

2.debug SSH

通過命令 ssh -vvv master 查看日志

OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to master [127.0.0.1] port 22. debug1: Connection established. debug1: identity file /home/hadoop/.ssh/identity type -1 debug1: identity file /home/hadoop/.ssh/identity-cert type -1 debug3: Not a RSA1 key file /home/hadoop/.ssh/id_rsa. debug2: key_type_from_name: unknown key type '-----BEGIN' debug3: key_read: missing keytype debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug3: key_read: missing whitespace debug2: key_type_from_name: unknown key type '-----END' debug3: key_read: missing keytype debug1: identity file /home/hadoop/.ssh/id_rsa type 1 debug1: identity file /home/hadoop/.ssh/id_rsa-cert type -1 debug1: identity file /home/hadoop/.ssh/id_dsa type -1 debug1: identity file /home/hadoop/.ssh/id_dsa-cert type -1 debug1: identity file /home/hadoop/.ssh/id_ecdsa type -1 debug1: identity file /home/hadoop/.ssh/id_ecdsa-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_5.3 debug2: fd 3 setting O_NONBLOCK debug1: SSH2_MSG_KEXINIT sent debug3: Wrote 960 bytes for a total of 981 debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,ssh-rsa,ssh-dss debug2: kex_parse_kexinit: 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: kex_parse_kexinit: 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: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: 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: kex_parse_kexinit: 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: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-md5 debug1: kex: server->client aes128-ctr hmac-md5 none debug2: mac_setup: found hmac-md5 debug1: kex: client->server aes128-ctr hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug3: Wrote 24 bytes for a total of 1005 debug2: dh_gen_key: priv key bits set: 114/256 debug2: bits set: 512/1024 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug3: Wrote 144 bytes for a total of 1149 debug3: check_host_in_hostfile: host master filename /home/hadoop/.ssh/known_hosts debug3: check_host_in_hostfile: host master filename /home/hadoop/.ssh/known_hosts debug3: check_host_in_hostfile: match line 5 debug1: Host 'master' is known and matches the RSA host key. debug1: Found key in /home/hadoop/.ssh/known_hosts:5 debug2: bits set: 525/1024 debug1: ssh_rsa_verify: signature correct debug2: kex_derive_keys debug2: set_newkeys: mode 1 debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug3: Wrote 16 bytes for a total of 1165 debug2: set_newkeys: mode 0 debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug3: Wrote 48 bytes for a total of 1213 debug2: service_accept: ssh-userauth debug1: SSH2_MSG_SERVICE_ACCEPT received debug2: key: /home/hadoop/.ssh/identity ((nil)) debug2: key: /home/hadoop/.ssh/id_rsa (0x2ae9888a6330) debug2: key: /home/hadoop/.ssh/id_dsa ((nil)) debug2: key: /home/hadoop/.ssh/id_ecdsa ((nil)) debug3: Wrote 64 bytes for a total of 1277 debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic,password debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password debug3: authmethod_lookup gssapi-keyex debug3: remaining preferred: gssapi-with-mic,publickey,keyboard-interactive,password debug3: authmethod_is_enabled gssapi-keyex debug1: Next authentication method: gssapi-keyex debug1: No valid Key exchange context debug2: we did not send a packet, disable method debug3: authmethod_lookup gssapi-with-mic debug3: remaining preferred: publickey,keyboard-interactive,password debug3: authmethod_is_enabled gssapi-with-mic debug1: Next authentication method: gssapi-with-mic debug3: Trying to reverse map address 127.0.0.1. debug1: Unspecified GSS failure. Minor code may provide more information Credentials cache file '/tmp/krb5cc_501' not founddebug1: Unspecified GSS failure. Minor code may provide more information Credentials cache file '/tmp/krb5cc_501' not founddebug1: Unspecified GSS failure. Minor code may provide more informationdebug1: Unspecified GSS failure. Minor code may provide more information Credentials cache file '/tmp/krb5cc_501' not founddebug2: 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: Trying private key: /home/hadoop/.ssh/identity debug3: no such identity: /home/hadoop/.ssh/identity debug1: Offering public key: /home/hadoop/.ssh/id_rsa debug3: send_pubkey_test debug2: we sent a publickey packet, wait for reply debug3: Wrote 368 bytes for a total of 1645 debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password debug1: Trying private key: /home/hadoop/.ssh/id_dsa debug3: no such identity: /home/hadoop/.ssh/id_dsa debug1: Trying private key: /home/hadoop/.ssh/id_ecdsa debug3: no such identity: /home/hadoop/.ssh/id_ecdsa 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

3.從日志信息并沒有看到是權限問題，通過比較可以正常免匙的機器發現以下不同：

在這期間我嘗試新建了用戶test，在新建的用戶中配置免匙ssh依然不行，但是發現root用戶的免匙SSH是ok的，現在目標又回到了權限問題，可是發現權限都是ok的。

4.在快要放棄的時候搜到了這篇帖子：http://www.linuxidc.com/Linux/2013-07/87267.htm

看了這篇文章后我立刻用ls -laZ檢查了我的.ssh目錄：

[hadoop@master ~]$ ls -laZ .ssh

drwx------. hadoop hadoop unconfined_u:object_r:file_t:s0? .

drwxr-xr-x. hadoop hadoop unconfined_u:object_r:file_t:s0? ..

-rw-------. hadoop hadoop unconfined_u:object_r:file_t:s0? authorized_keys

-rw-------. hadoop hadoop unconfined_u:object_r:file_t:s0? id_rsa

-rw-r--r--. hadoop hadoop unconfined_u:object_r:file_t:s0? id_rsa.pub

-rw-r--r--. hadoop hadoop unconfined_u:object_r:file_t:s0? id_rsa.pub.slave1

-rw-r--r--. hadoop hadoop unconfined_u:object_r:file_t:s0? id_rsa.pub.slave2

-rw-r--r--. hadoop hadoop unconfined_u:object_r:file_t:s0? known_hosts

我也是“果然不是ssh_home_t”。

5.解決問題：

切換到root用戶，修復context:

[root@master ~]# restorecon -r -vv /home/?

[hadoop@master ~]$ ls -laZ .ssh

drwx------. hadoop hadoop unconfined_u:object_r:ssh_home_t:s0 .

drwxr-xr-x. hadoop hadoop unconfined_u:object_r:user_home_dir_t:s0..

-rw-------. hadoop hadoop unconfined_u:object_r:ssh_home_t:s0 authorized_keys

-rw-------. hadoop hadoop unconfined_u:object_r:ssh_home_t:s0 id_rsa

-rw-r--r--. hadoop hadoop unconfined_u:object_r:ssh_home_t:s0 id_rsa.pub

-rw-r--r--. hadoop hadoop unconfined_u:object_r:ssh_home_t:s0 id_rsa.pub.slave1

-rw-r--r--. hadoop hadoop unconfined_u:object_r:ssh_home_t:s0 id_rsa.pub.slave2

-rw-r--r--. hadoop hadoop unconfined_u:object_r:ssh_home_t:s0 known_hosts

6.驗證是否解決：

[hadoop@master ~]$ ssh master

Last login: Wed May 31 09:01:48 2017 from 10.0.17.19

Starting Nexus OSS...

Started Nexus OSS.

-bash: /etc/profile.d/mystart.sh: line 2: syntax error near unexpected token `&&'

-bash: /etc/profile.d/mystart.sh: line 2: ` && '

[hadoop@master ~]$?

7.問題總結：

根本原因是我將/home/hadoop目錄做了移動，可是移動回來的時候用的是root用戶，即便我改回了hadoop:hadoop，可是目錄下的文件夾的context變了，而ssh鑒權又非常嚴格必須是ssh_home_t才可以。

總結

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