NERSC SVN/CVS server

NERSC hosts Subversion (SVN) and CVS repositories for NERSC projects. Access is by SSH only; pserver access is not supported. The NERSC server can be accessed as either svn.nersc.gov or cvs.nersc.gov. If you are starting a new project with version control we recommend using SVN over CVS.

Documentation

• Subversion Documentation
• NERSC Hands-on SVN Tutorial
• SVN Tutorial Overview Slides
• CVS documentation

How to get access to a SVN or CVS repositories

OS and Software Requirements

Getting Started

1. your user name on NERSC's SVN/CVS machine
2. the path name to the root of your project's repository on the NERSC CVS/SVN machine
3. the name of the SVN/CVS modules/directories you wish to access (unless you are creating new directories/modules)

Suggested Client Configuration

We will describe how to use NERSC's Power 5 system, Bassi, as an example client. Once you have an account on the server and know your repository name, perform these steps to configure your UNIX enviroment. (If you know what you are doing, you can configure your environment differently, but (I think) the following method provides for the most transparent access.)

If you do not want to configure your client as described below, you will have to provide your password on SSH passphrase with each cvs command you issue.

0. Create a .ssh directory in your home directory if it doesn't already exist.

1. Create a private key exclusively for SVN/CVS (You only have to do this step once.)

On your UNIX machine, run ssh-keygen as in this example on Bassi:

% ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/usr/common/homes/u/username/.ssh/id_rsa)
/usr/common/homes/u/username/.ssh/identity_svn
Enter passphrase (empty for no passphrase): choose a passphrase 
Enter same passphrase again: same passphrase as above
Your identification has been saved in /usr/common/homes/u/username/.ssh/identity_svn.
Your public key has been saved in /usr/common/homes/u/username/.ssh/identity_svn.pub.

Where you replace /usr/common/homes/u/username/ with the path to your home directory. This creates a public/private key pair. In order to access SVN/CVS without typing your passphrase with each command, run your shell under ssh-agent and use ssh-add to store your passphrase in memory.

2. Transfer your public key (You only have to do this step once.)

Obtain your password as directed in the email you received when your account was activated. Then use scp to copy the contents of the file identity_cvs.pub to your .ssh directory on svn.nersc.gov

% scp ~/.ssh/identity_svn.pub svn.nersc.gov:.ssh/authorized_keys2 
	

3. Create an SSH alias (optional)

On your UNIX machine (e.g. Bassi):

1. create a .ssh directory in your home directory if it doesn't already exist.
2. cd ~/.ssh
3. edit a file named config
4. Add these lines to the config file

   Host 		svnserver
   HostName 	svn.nersc.gov
   User 		your_login_name
   IdentityFile 	~/.ssh/identity_svn
   Protocol	2
   

4. Set environment variables (CVS only) (You only have to do this step once on each UNIX client.)

csh, tcsh users: Edit ~/.cshrc, ~/.cshrc.ext, ~/.tcshrc or other applicable shell initialization file to include these lines:

setenv CVSROOT cvsserver:/cvs/your_cvsrepository_root
setenv CVS_RSH ssh

sh, ksh, bash users: Edit ~/.profile, ~/.bash_profile or other applicable shell initialization file to include these lines:

export CVSROOT=cvsserver:/cvs/your_cvsrepository_root
export CVS_RSH=ssh	

You may have to replace ssh with the full path specification to your ssh binary.

Source these files or log out and log back into the UNIX machine you are using.

Your account on the server

You have an account on the NERSC server, but it is restricted to running a very few commands.

Logins and passwords on the SVN/CVS server are subject to the NERSC Account Ownership Policy.

To use SVN checkout a repository with the following command.

svn checkout svn+ssh://svn.nersc.gov/svn/your_repository_name

For CVS If you use the procedures outlined above, you do not need to use a password. However, if you wish to connect to the server from a machine that is not configured as described, you may use a password to access CVS. If you have not performed the configuration described above, you can access the server using the following syntax:

cvs -d user@cvs.nersc.gov:/cvs/your_repository_root cvs_commands