Install Apache Subversion on Ubuntu 20.04

Apache Subversion is an open source version control system released in 2000 and available under the Apache2 License. Designed as a feature enhancement of the Concurrent Versions System(CVS), Apache Subversion was authored and maintained by Collabnet. In 2009, Subversion became an Apache Incubator Project, finally becoming a top-level project in 2010. In this guide you learn how to install Apache’s Subversion on an Ubuntu 20.04 server.

What is Apache Subversion?

Apache Subversion is a version control system(VCS) that manages, documents, and organizes the changes made to a project’s files and directories. Subversion can work across networks to manage the same files and directories. This enables collaboration between developers who are working on the same codebase. Although Subversion is commonly used to version control software development projects, you can use it to version control any group of files and directories. Apache Subversion is invoked on the command line using the svn command. For this reason it is sometimes also referred to as SVN.

Apache Subversion is made up of two primary components:

• Server: the server is used to store the Subversion repository.
• Client: the client application is used to organize updates to and from the Subversion server that stores the project repository.

The list below breaks down the Subversion components you need to install on a system based on your role within a Subversion project:

The Subversion server is a web-based repository consisting of a trunk and branches. Clients work on branches of the trunk until they are ready to be made a part of the trunk repository. A trunk and its branches are a base directory, while directories are branches.

There can be more than one client that accesses the server at the same time. The server instance must remain available and accessible to all clients. Both client and server can be hosted on the same Ubuntu 20.04 instance.

This tutorial covers the steps for installing Subversion on Ubuntu Server 20.04 LTS. However, you can install Apache Subversion on Linux, macOS, and Windows systems.

Apache Subversion vs. Git

Apache Subversion provides a different workflow and version control methodology compared to Git and its derivatives. The table below lists some of the differences between Apache Subversion and Git.

Apache Subversion Installation Steps

Prerequisites

The steps in this tutorial demonstrate how to use the APT package manager to install Apache Subversion. There are pre-compiled binaries of SVN available too.

• If you are connecting to an existing Subversion server, then an Apache Subversion Client is the minimum installation required.

• If you need a full installation of Apache Subversion for local use, then it requires both the client and server components.

• Deploy a new Linode and follow the steps below. You can also follow the steps in the How to Install a LAMP Stack on Ubuntu 20.04 guide.

• If you choose to follow the steps in the LAMP stack guide or already have a server with a LAMP stack installed, skip the Install the Apache Web Server section below, and move on to the Install Apache Subversion section after updating your Ubuntu 20.04 system.

• Update your Ubuntu 20.04 system:

  sudo apt update
  sudo apt upgrade
  

Install the Apache Web Server

1. Log in to Ubuntu 20.04 LTS Linode instance as a limited user.

2. Install the Apache server instance with the following command:

    sudo apt install apache2 apache2-utils -y
   

3. Use systemctl to start Apache.

    systemctl start apache2
   

4. To verify that the installation was successful, open a browser window and enter the Linode instance’s IP address, http://<<host IP address>>:80.

5. If the instance is not accessible, the instance hosting Apache might require opening firewall ports. To enable ufw to let traffic flow between interfaces and the Apache daemon, you must instruct ufw to open ports for Apache.

    sudo ufw allow 'Apache'
   

   This opens port 80.

6. Enable the Apache instance you just installed. The following command starts Apache during subsequent reboots.

    sudo systemctl enable apache2
   

Install Apache Subversion

The steps in this section show you how to install the Apache Subversion client from Ubuntu’s repositories.

1. Install Apache Subversion library dependencies from Ubuntu repositories. These are not included in the Ubuntu 20.04 LTS distributions and must be added first.

    sudo apt install libsvn-dev libapache2-mod-svn subversion-tools
   

2. Install Subversion.

    sudo apt install subversion -y
   

3. Apache has specific modules that must be enabled for Apache Subversion. Enable the following modules to allow Apache to work with Subversion.

    sudo a2enmod dav
    sudo a2enmod dav_svn
   

   The above a2enmod command enables the dav and the dav_svn module. This is done one time only.

4. Restart Apache to enable the changes.

    sudo systemctl restart apache2
   

Create A Subversion Administrator User

No user can link the SVN app with the repository until an administrative account is made. The following command shows you how to create a Subversion administrator user.

Create a Subversion administrator user. Replace <<admin_name>> with the desired administrator name.

htpasswd -cm /etc/apache2/dav_svn.passwd <<admin_name>>

Apache Subversion Configuration and Repository Examples

The links between the Subversion client and the modules used for the Apache repository must be defined in a configuration file. The steps in this section include a sample configuration file that links the dav_svn module.

1. In your system’s /etc/apache2/mods_enabled/ directory, create an example file named dav_svn.conf.

2. Add the example content to the dav_svn.conf file. The example configuration below demonstrate how to configure repository authentication and access control.

   File: dav_svn.conf

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55

   # dav_svn.conf - Example Subversion/Apache configuration # # For details and further options see the Apache user manual and # the Subversion book. # # NOTE: for a setup with multiple vhosts, you will want to do this # configuration in /etc/apache2/sites-available/*, not here. # <Location URL> ... </Location> # URL controls how the repository appears to the outside world. # In this example clients access the repository as http://hostname/svn/ # Note, a literal /svn should NOT exist in your document root. <Location /svn> # Uncomment this to enable the repository DAV svn # Set this to the path to your repository; our example uses a path of /var/www/svn SVNPath /var/www/svn # Alternatively, use SVNParentPath if you have multiple repositories under # under a single directory (/var/lib/svn/repo1, /var/lib/svn/repo2, ...). # You need either SVNPath and SVNParentPath, but not both. #SVNParentPath /var/www/svn # Access control is done at 3 levels: (1) Apache authentication, via # any of several methods. A "Basic Auth" section is commented out # below. (2) Apache <Limit> and <LimitExcept>, also commented out # below. (3) mod_authz_svn is a svn-specific authorization module # which offers fine-grained read/write access control for paths # within a repository. (The first two layers are coarse-grained; you # can only enable/disable access to an entire repository.) Note that # mod_authz_svn is noticeably slower than the other two layers, so if # you don't need the fine-grained control, don't configure it. # Basic Authentication is repository-wide. It is not secure unless # you are using https. See the 'htpasswd' command to create and # manage the password file - and the documentation for the # 'auth_basic' and 'authn_file' modules, which you will need for this # (enable them with 'a2enmod'). AuthType Basic AuthName "Subversion Repository" #AuthUserFile /etc/apache2/dav_svn.passwd # To enable authorization via mod_authz_svn #AuthzSVNAccessFile /etc/apache2/dav_svn.authz # The following three lines allow anonymous read, but make # committers authenticate themselves. It requires the 'authz_user' # module (enable it with 'a2enmod'). #<LimitExcept GET PROPFIND OPTIONS REPORT> #Require valid-user #</LimitExcept> #</Location>

   Note

   You may need to restart Subversion using systemctl for your configuration changes to take effect.

An Example Subversion Directory Structure

Subversion does not enforce a directory structure. The three directories commonly used are trunk, tags, and branches. By convention, SVN uses a root directory for each project, with trunk/tags/branches as children of the project’s root directory. The example below displays Subversion server’s directory structure:

/
  project1/
    /trunk
    /tags
    /branches
  project2/
    /trunk
    /tags
    /branches
  project3/
    /trunk
    /tags
    /branches
  ...
  ...
  projectn/
    /trunk
    /tags
    /branches

Access Apache Subversion Web Interface

You can access your Subversion repository by pointing your browser to the Apache Subversion repository service with the following URL:

http://<<server IP or FQDN>>/svn/<<name of project>>

This URL accesses the desired Subversion project. Ensure you replace all values with your own Subversion server’s information.

Conclusion

The SVN Book is a must-read for those who manage projects using Apache Subversion. There are many tools that support the use of Subversion, including GUIs like TortoiseSVN.

You should make sure to back up your Apache Subversion repository at reasonable intervals. One way to do so is by backing up your Subversion server using the Linode Backup service.

Refer to our How to Install and Use the Subversion CLI Client for client installation steps, along with the essential commands to support a Subversion workflow.