ssh password-less session config

Sometimes , we need ssh without password authorization when deloyed the same file into servers within domain. The most implementation are "Cluster" project(even some distributed systems). All Cluster project needed servers to be deployed with the same config file. In my project is about , a kind of Cluster, the Google Bigtable(Hypertable) with GFS(Google File System).  Deployment is the best important when I need to maintain these servers in several data centers.

Server B ---ssh---> Server A ,without password
(1)@ServerB
    shell> ssh-keygen -t dsa

    (Just Enter,Enter,Enter)
    there were 2 files (id_dsa, id_dsa.pub) at ~/.ssh

    shell> scp ~/.ssh/id_dsa.pub [@serverA]:~/.ssh/B_dsa.pub

(2)@ServerA
    shell> cd ~/.ssh
    shell> cat B_dsa.pub >> ~/.ssh/authorized_keys

(3)@ServerB
    shell> ssh serverA
   
[Supplementary]
##1. ssh without interaction and passphrase ,add by sean in 2012/11/27
##1-1. Generate a key in ssh client , with temporary key '123456'. file name as hostname
[root@client ~]# ssh-keygen -t dsa -N "123456" -f ~/.ssh/$(hostname)

##1-2. Remove passphrase inside private key(~/.ssh/id_dsa), ~/.ssh/id_dsa should be with permission 600

[root@client ~]# openssl dsa -in ~/.ssh/$(hostname) -out ~/.ssh/id_dsa -passin pass:123456

[root@client ~]# chmod 600 ~/.ssh/id_dsa

##1-3. copy public key to the server [192.168.122.11]

[root@client ~]# scp ~/.ssh/$(hostname).pub 192.168.122.11:~/.ssh/.

[root@client ~]# rsync -av /root/.ssh/$(hostname).pub 192.168.122.11:/root/.ssh/$(hostname).pub

##1-4. merge all client's public-key into ~/.ssh/authorized_keys

[root@client ~]# cd ~/.ssh

[root@client ~]# cp client1.pub client2.pub ... authorized_keys

##2. no message prompt when a new-host ssh connection had been built ,add by sean in 2012/11/27

##2-1. command-line option connect to server(192.168.122.11)

[root@client ~]# ssh -o StrictHostKeyChecking=no' -o 'BatchMode=yes' 192.168.122.11
###  StrictHostKeyChecking=no : add host key directly(no ask) into ~/.ssh/know_hosts

###  BatchMode=yes : no interactive when connecting to server

##2-2. config in client ( when you modifed the config , you don't need to connect to serve with options (-o)

[root@client ~]# vi /etc/ssh/ssh_config
  :
  :
StrictHostKeyChecking=no
BatchMode=yes

##3. administration when host changed (changed ip , OS re-install...)  ,add by sean in 2012/11/27

##3-1. remove client's(192.168.122.15) old key

[root@server ~]# ssh-keygen -R 192.168.122.15

##3-2. scan client's new key and append into ~/.ssh/known_hosts

[root@server ~]# ssh-keyscan 192.168.122.15 | tee -a ~/.ssh/known_hosts

##3-3. scan server's key and append into ~/.ssh/known_hosts

[root@client ~]# ssh-keyscan 192.168.122.11 | tee -a ~/.ssh/known_hosts