搭建hadoop伪分布节点时ssh的设置

目标：ssh localhost 无需键入密码

步骤 ：
前提：确认主机安装ssh shhd 分别是 ssh客户端和server端
使用hadoop账户
方法一：
ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa

cat ~/.ssh/id_dsa.pub
>> ~/.ssh/authorized_keys

[root@localhost hadoop]# ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa

Generating public/private dsa key pair.

Your identification has been saved in /root/.ssh/id_dsa.

Your public key has been saved in /root/.ssh/id_dsa.pub.

The key fingerprint is:

42:19:31:10:b4:59:09:f7:47:3f:82:f4:70:dc:79:89 root@localhost

[root@localhost hadoop]# cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

建立好这些文件后，无需修改sshd_config或ssh_config文件
ssh客户端默认会在passwd验证之前，在本地~/.ssh目录下寻找dsa、rsa等加密方式的密钥文件，看能否免除密码键入的验证步骤
做好上述配置后，ssh localhost 无需输入密码

[root@localhost hadoop]# ssh localhost

Last login: Thu Aug 29 00:34:56 2013
ssh -vv localhost 显示debug信息如下：

[root@localhost ~]# ssh -vv localhost

OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008

debug1: Reading configuration data /etc/ssh/ssh_config

debug1: Applying options for *

debug2: ssh_connect: needpriv 0

debug1: Connecting to localhost [127.0.0.1] port 22.

debug1: Connection established.

debug1: permanently_set_uid: 0/0

debug1: identity file /root/.ssh/identity type -1

debug1: identity file /root/.ssh/id_rsa type -1

debug2: key_type_from_name: unknown key type '-----BEGIN'

debug2: key_type_from_name: unknown key type '-----END'

debug1: identity file /root/.ssh/id_dsa type 2

debug1: loaded 3 keys

debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3

debug1: match: OpenSSH_4.3 pat OpenSSH*

debug1: Enabling compatibility mode for protocol 2.0

debug1: Local version string SSH-2.0-OpenSSH_4.3

debug2: fd 3 setting O_NONBLOCK

debug1: SSH2_MSG_KEXINIT sent

debug1: SSH2_MSG_KEXINIT received

debug2: kex_parse_kexinit: 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-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr

debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr

debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96

debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,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-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1

debug2: kex_parse_kexinit: ssh-rsa,ssh-dss

debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr

debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr

debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96

debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,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_init: found hmac-md5

debug1: kex: server->client aes128-cbc hmac-md5 none

debug2: mac_init: found hmac-md5

debug1: kex: client->server aes128-cbc hmac-md5 none

debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent

debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP

debug2: dh_gen_key: priv key bits set: 133/256

debug2: bits set: 488/1024

debug1: SSH2_MSG_KEX_DH_GEX_INIT sent

debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY

debug1: Host 'localhost' is known and matches the RSA host key.

debug1: Found key in /root/.ssh/known_hosts:1

debug2: bits set: 519/1024

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

debug2: set_newkeys: mode 0

debug1: SSH2_MSG_NEWKEYS received

debug1: SSH2_MSG_SERVICE_REQUEST sent

debug2: service_accept: ssh-userauth

debug1: SSH2_MSG_SERVICE_ACCEPT received

debug2: key: /root/.ssh/identity ((nil))

debug2: key: /root/.ssh/id_rsa ((nil))

debug2: key: /root/.ssh/id_dsa (0x9854f20)

debug1: Authentications that can continue: publickey,gssapi-with-mic,password

debug1: Next authentication method: gssapi-with-mic

debug1: Unspecified GSS failure. Minor code may provide more information

No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information

No credentials cache found

debug1: Unspecified GSS failure. Minor code may provide more information

No credentials cache found

debug2: we did not send a packet, disable method

debug1: Next authentication method: publickey

debug1: Trying private key: /root/.ssh/identity

debug1: Trying private key: /root/.ssh/id_rsa

debug1: Offering public key: /root/.ssh/id_dsa

debug2: we sent a publickey packet, wait for reply

debug1: Server accepts key: pkalg ssh-dss blen 434

debug2: input_userauth_pk_ok: SHA1 fp 3b:ad:d7:dd:48:2a:fc:32:ec:cc:21:40:28:57:b3:d6:f3:da:dc:e3

debug1: read PEM private key done: type DSA

debug1: Authentication succeeded (publickey).

debug1: channel 0: new [client-session]

debug2: channel 0: send open

debug1: Entering interactive session.

debug2: callback start

debug2: client_session2_setup: id 0

debug2: channel 0: request pty-req confirm 0

debug1: Sending environment.

debug1: Sending env LANG = en_US.UTF-8

debug2: channel 0: request env confirm 0

debug2: channel 0: request shell confirm 0

debug2: fd 3 setting TCP_NODELAY

debug2: callback done

debug2: channel 0: open confirm rwindow 0 rmax 32768

debug2: channel 0: rcvd adjust 2097152

Last login: Thu Aug 29 01:09:26 2013 from localhost.localdomain

由上面debug信息可知，ssh在尝试发送rsa或dsa的public key，但是并没有发送出去we did not send a packet, disable method

猜测是权限问题
将.ssh权限改为700（原来是777）
authorized_keys 权限改为600 （原来是666）
[root@localhost ~]# cd ~/.ssh

[root@localhost .ssh]# ls

authorized_keys id_dsa id_dsa.pub known_hosts

[root@localhost .ssh]# chmod 600 authorized_keys

[root@localhost .ssh]# cd ..

[root@localhost ~]# chmod 700 .ssh/

如此之后
ssh localhost
无需输入密码
配置成功

方法二：
使用hadoop用户配置ssh

ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/home/ hadoop /.ssh/id_rsa):

--此处填写默认路径

Enter passphrase (empty for no passphrase): --此处回车，空密码

Enter same passphrase again: --此处回车，空密码

Your identification has been saved in /home/ hadoop /.ssh/id_rsa.

Your public key has been saved in /home/ hadoop /.ssh/id_rsa.pub.

这将在/home/hadoop/.ssh/目录下生成一个私钥id_rsa和一个公钥id_rsa.pub。

在namenode节点上做如下配置：cp id_rsa.pub authorized_keys

--namenode的公钥

这样配置过后，namenode可以无密码登录本身，可以通过命令ssh localhost来验证