Varnish Cache is a high-performance HTTP accelerator designed to cache HTTP responses to reduce the load on your backend servers. When configured properly, it can significantly speed up your website by serving cached content to users, reducing server load, and improving user experience. Varnish is often used in conjunction with web servers like Nginx or Apache. This guide will walk you through installing Varnish on a VPS, configuring it, and integrating it with your existing web server for maximum performance.
Step 1: Set Up Your VPS
Before we begin, ensure that you have a VPS running with a clean installation of Ubuntu 20.04 LTS or later. You can use any VPS provider like DigitalOcean, Linode, Vultr, or AnonVM for this setup.
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Create a VPS
- Choose a VPS with at least 1GB of RAM. For better performance, a VPS with 2GB of RAM or more is recommended.
- Use Ubuntu 20.04 LTS as the operating system, but this guide can work on other Linux distributions with slight adjustments.
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SSH Into Your VPS
- After creating your VPS, connect to it via SSH:
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Update Your System
- Make sure your system is up-to-date:
Step 2: Install Varnish Cache
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Add Varnish Repository
- To install the latest stable version of Varnish, add its official repository to your system:
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Install Varnish
- Now, install Varnish Cache:
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Verify the Installation
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After installation, verify that Varnish is installed correctly by checking its version:
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You should see output indicating the installed version of Varnish.
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Step 3: Configure Varnish Cache
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Default Configuration Location
- The main Varnish configuration file is located at
/etc/varnish/default.vcl
. You’ll need to edit this file to define caching rules and backends.
- The main Varnish configuration file is located at
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Configure the Backend Server
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Open the
default.vcl
file in your favorite text editor: -
Set up your backend server, typically pointing to your web server (e.g., Nginx or Apache) which is running on port 8080:
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Configure Varnish to Listen on Port 80
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By default, Varnish listens on port 6081. We’ll change it to port 80 to handle incoming web traffic. Open the Varnish service configuration file:
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Modify the file to configure Varnish to listen on port 80:
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Save and exit the file.
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Adjust Firewall Rules (if necessary)
- If you have a firewall running, make sure ports 80 (HTTP) and 6082 (for Varnish administration) are open:
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Enable and Restart Varnish
- After modifying the configuration, reload the Varnish service:
Step 4: Integrate Varnish with Your Web Server (Nginx/Apache)
If you are using a web server like Nginx or Apache, you need to configure it to listen on a different port (e.g., 8080) because Varnish will now handle requests on port 80.
For Nginx:
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Modify Nginx to Listen on Port 8080
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Edit the Nginx configuration to make it listen on port 8080 instead of port 80:
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Change the
listen
directive from80
to8080
:
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Restart Nginx
- After saving the configuration, restart Nginx to apply the changes:
For Apache:
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Modify Apache to Listen on Port 8080
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Open Apache’s ports configuration:
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Add a
Listen 8080
directive if it is not already present:
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Modify Virtual Hosts
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Edit your virtual host configuration file to make Apache listen on port 8080:
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Change the
VirtualHost
directive to use port 8080:
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Restart Apache
- Restart Apache to apply the changes:
Step 5: Test Varnish Cache
Once Varnish is up and running, test its cache functionality:
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Verify Cache Headers
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Use
curl
to send a request to your website and check if Varnish is caching responses: -
Look for the
X-Varnish
andVia
headers in the response: -
If you see these headers, Varnish is successfully caching responses.
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Clear Cache (Optional)
- You can clear the Varnish cache if needed by running:
Step 6: Tune Varnish Cache (Optional)
To further optimize Varnish performance, consider the following settings:
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Increase Cache Size
- You can increase the memory allocated for caching by editing the
app.vcl
file or thevarnish.service
file to allocate more memory for Varnish's storage backend. For example:
- You can increase the memory allocated for caching by editing the
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Cache Time-to-Live (TTL)
- You can define how long content is cached by setting a TTL value in your
default.vcl
file:
- You can define how long content is cached by setting a TTL value in your
Conclusion
You have now installed and configured Varnish Cache on your VPS to improve web performance. By caching HTTP responses, Varnish reduces server load and speeds up your website, providing a better experience for users. With proper configuration and tuning, Varnish can handle high traffic loads and serve cached content quickly.