Setting up ssh on cluster systems<a class="indexterm" name="id427005"></a><a class="indexterm" name="id427011"></a>


Setting up ssh on cluster systems
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Setting up ssh on cluster systems

Use the Secure Shell (ssh) to install VCS on all systems in a cluster from a system outside of the cluster. Before you start the installation process, verify that ssh is configured correctly.

Use Secure Shell (ssh) to do the following:

Log on to another system over a network
Execute commands on a remote system
Copy files from one system to another

The ssh shell provides strong authentication and secure communications over channels. It is intended to replace rlogin, remsh, and rcp.

Configuring ssh

The procedure to configure ssh uses OpenSSH example file names and commands.

Note:

You can configure ssh in other ways. Regardless of how ssh is configured, complete the last step in the example to verify the configuration.

To configure ssh

Log on to the system from which you want to install VCS.
Generate a DSA key pair on this system by running the following command:
```
# ssh-keygen -t dsa
```
Accept the default location of ~/.ssh/id_dsa.
When the command prompts, enter a passphrase and confirm it.
Change the permissions of the .ssh directory by typing:
```
# chmod 755 ~/.ssh
```
The file ~/.ssh/id_dsa.pub contains a line that begins with ssh_dss and ends with the name of the system on which it was created. Copy this line to the /.ssh/authorized_keys file on all systems where you plan to installVCS.

If the local system is part of the cluster, make sure to edit the authorized_keys file on that system.
Run the following commands on the system where you are installing:
```
# exec /usr/bin/ssh-agent $SHELL
# ssh-add
```
This step is shell-specific and is valid for the duration the shell is alive.
When the command prompts, enter your DSA passphrase.
You are ready to install VCS on several systems in one of the following ways:
- Run the installvcs program on any one of the systems
- Run the installvcs program on an independent system outside the cluster
To verify that you can connect to the systems where you plan to install VCS, type:
```
# ssh -x -l root north ls
# ssh -x -l root south ifconfig lan0
```
The commands should execute on the remote system without having to enter a passphrase or password.