With Oracle Database 11g Release 2, Oracle provides an extremely useful script to establish and exchange ssh keys between all the nodes of the cluster called sshUserSetup.sh. This script is available to everyone from the installation media in the grid/sshsetup sub-directory.

This little shell script comes in handy if you are cloning Oracle RAC clusters and do not want to leverage the GUI tools. If you trying to automate Oracle RAC build deployments, it is a must have tool for the DBAs. Without setting up ssh keys, the cluvfy script will fail and spit out the following error:

ERROR: User equivalence unavailable on all the nodes. Verification cannot proceed.

The following example demonstrates the sshUserSetup script executed on a 2-node RAC called rac1 and rac2:

[oracle@rac1 sshsetup]$ pwd
/nfs/software/12c/grid/sshsetup
 
[oracle@rac1 home]$ cd /nfs/software/12c/grid/sshsetup/

[oracle@rac1 sshsetup]$ ./sshUserSetup.sh -user oracle -hosts "rac1 rac2" -noPromptPassphrase -advanced -exverify
The output of this script is also logged into /tmp/sshUserSetup_2013-07-09-16-31-50.log
Hosts are rac1 rac2
user is oracle
Platform:- Linux
Checking if the remote hosts are reachable
PING rac1 (172.16.41.40) 56(84) bytes of data.
64 bytes from rac1 (172.16.41.40): icmp_seq=1 ttl=64 time=0.020 ms
64 bytes from rac1 (172.16.41.40): icmp_seq=2 ttl=64 time=0.032 ms
64 bytes from rac1 (172.16.41.40): icmp_seq=3 ttl=64 time=0.057 ms
64 bytes from rac1 (172.16.41.40): icmp_seq=4 ttl=64 time=0.030 ms
64 bytes from rac1 (172.16.41.40): icmp_seq=5 ttl=64 time=0.030 ms
 
--- rac1 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4007ms
rtt min/avg/max/mdev = 0.020/0.033/0.057/0.014 ms
PING rac2 (172.16.41.41) 56(84) bytes of data.
64 bytes from rac2 (172.16.41.41): icmp_seq=1 ttl=64 time=0.256 ms
64 bytes from rac2 (172.16.41.41): icmp_seq=2 ttl=64 time=0.303 ms
64 bytes from rac2 (172.16.41.41): icmp_seq=3 ttl=64 time=0.255 ms
64 bytes from rac2 (172.16.41.41): icmp_seq=4 ttl=64 time=0.306 ms
64 bytes from rac2 (172.16.41.41): icmp_seq=5 ttl=64 time=0.350 ms
 
--- rac2 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4009ms
rtt min/avg/max/mdev = 0.255/0.294/0.350/0.035 ms
Remote host reachability check succeeded.
The following hosts are reachable: rac1 rac2.
The following hosts are not reachable: .
All hosts are reachable. Proceeding further...
firsthost rac1
numhosts 2
The script will setup SSH connectivity from the host rac1 to all
the remote hosts. After the script is executed, the user can use SSH to run
commands on the remote hosts or copy files between this host rac1
and the remote hosts without being prompted for passwords or confirmations.
 
NOTE 1:
As part of the setup procedure, this script will use ssh and scp to copy
files between the local host and the remote hosts. Since the script does not
store passwords, you may be prompted for the passwords during the execution of
the script whenever ssh or scp is invoked.
 
NOTE 2:
AS PER SSH REQUIREMENTS, THIS SCRIPT WILL SECURE THE USER HOME DIRECTORY
AND THE .ssh DIRECTORY BY REVOKING GROUP AND WORLD WRITE PRIVILEDGES TO THESE
directories.
 
Do you want to continue and let the script make the above mentioned changes (yes/no)?
yes
 
The user chose yes
User chose to skip passphrase related questions.
Creating .ssh directory on local host, if not present already
Creating authorized_keys file on local host
Changing permissions on authorized_keys to 644 on local host
Creating known_hosts file on local host
Changing permissions on known_hosts to 644 on local host
Creating config file on local host
If a config file exists already at /home/oracle/.ssh/config, it would be backed up to /home/oracle/.ssh/config.backup.
Removing old private/public keys on local host
Running SSH keygen on local host with empty passphrase
Generating public/private rsa key pair.
Your identification has been saved in /home/oracle/.ssh/id_rsa.
Your public key has been saved in /home/oracle/.ssh/id_rsa.pub.
The key fingerprint is:
0f:b7:d8:17:6d:00:4f:b5:90:29:6a:a9:10:28:37:63 oracle@rac1
The key's randomart image is:
+--[ RSA 1024]----+
|   .      . o+.  |
|. E .     .+o. . |
| + o .   o .o .  |
|    .   +    o   |
|     . oS . . o  |
|      .  * . o   |
|        . + .    |
|           .     |
|                 |
+-----------------+
Creating .ssh directory and setting permissions on remote host rac1
THE SCRIPT WOULD ALSO BE REVOKING WRITE PERMISSIONS FOR group AND others ON THE HOME DIRECTORY FOR oracle. THIS IS AN SSH REQUIREMENT.
The script would create ~oracle/.ssh/config file on remote host rac1. If a config file exists already at ~oracle/.ssh/config, it would be backed up to ~oracle/.ssh/config.backup.
The user may be prompted for a password here since the script would be running SSH on host rac1.
Warning: Permanently added 'rac1,172.16.41.40' (RSA) to the list of known hosts.
oracle@rac1's password:
Done with creating .ssh directory and setting permissions on remote host rac1.
Creating .ssh directory and setting permissions on remote host rac2
THE SCRIPT WOULD ALSO BE REVOKING WRITE PERMISSIONS FOR group AND others ON THE HOME DIRECTORY FOR oracle. THIS IS AN SSH REQUIREMENT.
The script would create ~oracle/.ssh/config file on remote host rac2. If a config file exists already at ~oracle/.ssh/config, it would be backed up to ~oracle/.ssh/config.backup.
The user may be prompted for a password here since the script would be running SSH on host rac2.
Warning: Permanently added 'rac2,172.16.41.41' (RSA) to the list of known hosts.
oracle@rac2's password:
Done with creating .ssh directory and setting permissions on remote host rac2.
Copying local host public key to the remote host rac1
The user may be prompted for a password or passphrase here since the script would be using SCP for host rac1.
oracle@rac1's password:
Done copying local host public key to the remote host rac1
Copying local host public key to the remote host rac2
The user may be prompted for a password or passphrase here since the script would be using SCP for host rac2.
oracle@rac2's password:
Done copying local host public key to the remote host rac2
Creating keys on remote host rac1 if they do not exist already. This is required to setup SSH on host rac1.
 
Creating keys on remote host rac2 if they do not exist already. This is required to setup SSH on host rac2.
Generating public/private rsa key pair.
Your identification has been saved in .ssh/id_rsa.
Your public key has been saved in .ssh/id_rsa.pub.
The key fingerprint is:
f4:1d:b5:7e:a7:f5:ea:97:24:16:23:01:d7:17:47:c4 oracle@rac2
The key's randomart image is:
+--[ RSA 1024]----+
|         .... .==|
|          .. o oE|
|        .   o o  |
|       . . o =   |
|        S . o + +|
|             o =o|
|            . + o|
|               o.|
|             .o. |
+-----------------+
Updating authorized_keys file on remote host rac1
Updating known_hosts file on remote host rac1
Updating authorized_keys file on remote host rac2
Updating known_hosts file on remote host rac2
cat: /home/oracle/.ssh/known_hosts.tmp: No such file or directory
cat: /home/oracle/.ssh/authorized_keys.tmp: No such file or directory
SSH setup is complete.
 
------------------------------------------------------------------------
Verifying SSH setup
===================
The script will now run the date command on the remote nodes using ssh
to verify if ssh is setup correctly. IF THE SETUP IS CORRECTLY SETUP,
THERE SHOULD BE NO OUTPUT OTHER THAN THE DATE AND SSH SHOULD NOT ASK FOR
PASSWORDS. If you see any output other than date or are prompted for the
password, ssh is not setup correctly and you will need to resolve the
issue and set up ssh again.
The possible causes for failure could be:
1. The server settings in /etc/ssh/sshd_config file do not allow ssh
for user oracle.
2. The server may have disabled public key based authentication.
3. The client public key on the server may be outdated.
4. ~oracle or ~oracle/.ssh on the remote host may not be owned by oracle.
5. User may not have passed -shared option for shared remote users or
may be passing the -shared option for non-shared remote users.
6. If there is output in addition to the date, but no password is asked,
it may be a security alert shown as part of company policy. Append the
additional text to the <OMS HOME>/sysman/prov/resources/ignoreMessages.txt file.
------------------------------------------------------------------------
--rac1:--
Running /usr/bin/ssh -x -l oracle rac1 date to verify SSH connectivity has been setup from local host to rac1.
IF YOU SEE ANY OTHER OUTPUT BESIDES THE OUTPUT OF THE DATE COMMAND OR IF YOU ARE PROMPTED FOR A PASSWORD HERE, IT MEANS SSH SETUP HAS NOT BEEN SUCCESSFUL. Please note that being prompted for a passphrase may be OK but being prompted for a password is ERROR.
Tue Jul  9 16:32:24 CDT 2013
------------------------------------------------------------------------
--rac2:--
Running /usr/bin/ssh -x -l oracle rac2 date to verify SSH connectivity has been setup from local host to rac2.
IF YOU SEE ANY OTHER OUTPUT BESIDES THE OUTPUT OF THE DATE COMMAND OR IF YOU ARE PROMPTED FOR A PASSWORD HERE, IT MEANS SSH SETUP HAS NOT BEEN SUCCESSFUL. Please note that being prompted for a passphrase may be OK but being prompted for a password is ERROR.
Tue Jul  9 16:32:25 CDT 2013
------------------------------------------------------------------------
------------------------------------------------------------------------
Verifying SSH connectivity has been setup from rac1 to rac1
------------------------------------------------------------------------
IF YOU SEE ANY OTHER OUTPUT BESIDES THE OUTPUT OF THE DATE COMMAND OR IF YOU ARE PROMPTED FOR A PASSWORD HERE, IT MEANS SSH SETUP HAS NOT BEEN SUCCESSFUL.
Tue Jul  9 16:32:25 CDT 2013
------------------------------------------------------------------------
------------------------------------------------------------------------
Verifying SSH connectivity has been setup from rac1 to rac2
------------------------------------------------------------------------
IF YOU SEE ANY OTHER OUTPUT BESIDES THE OUTPUT OF THE DATE COMMAND OR IF YOU ARE PROMPTED FOR A PASSWORD HERE, IT MEANS SSH SETUP HAS NOT BEEN SUCCESSFUL.
Tue Jul  9 16:32:26 CDT 2013
------------------------------------------------------------------------
-Verification from rac1 complete-
------------------------------------------------------------------------
Verifying SSH connectivity has been setup from rac2 to rac1
------------------------------------------------------------------------
IF YOU SEE ANY OTHER OUTPUT BESIDES THE OUTPUT OF THE DATE COMMAND OR IF YOU ARE PROMPTED FOR A PASSWORD HERE, IT MEANS SSH SETUP HAS NOT BEEN SUCCESSFUL.
Tue Jul  9 16:32:26 CDT 2013
------------------------------------------------------------------------
------------------------------------------------------------------------
Verifying SSH connectivity has been setup from rac2 to rac2
------------------------------------------------------------------------
IF YOU SEE ANY OTHER OUTPUT BESIDES THE OUTPUT OF THE DATE COMMAND OR IF YOU ARE PROMPTED FOR A PASSWORD HERE, IT MEANS SSH SETUP HAS NOT BEEN SUCCESSFUL.
Tue Jul  9 16:32:27 CDT 2013
------------------------------------------------------------------------
-Verification from rac2 complete-
SSH verification complete.

Now user equivalence is setup between rac1 and rac2. Let’s confirm by connecting to each of the nodes as oracle:

[oracle@rac1 sshsetup]$ ssh rac2

[oracle@rac2 ~]$ exit
logout
Connection to rac2 closed.
 
[oracle@rac2 ~]$ ssh rac1

Last login: Tue Jul  9 16:20:13 2013 from 192.168.225.1
[oracle@rac1 ~]$ exit 

Comments are closed