Varnish is an open-source HTTP accelerator. It is usually configured to sit in front of web servers to serve HTTP/HTTPS requests quickly. Varnish can also be a load balancer to distribute loads across multiple web servers.
This brief tutorial will show students and new users how to install and configure Varnish with Apache2 on Ubuntu 17.04 | 17.10.
In this post, we’ll set up Varnish as the doorway or front-end to Apache2 to serve HTTP requests quickly.
Configuring Varnish as the front end to Apache2 or other web servers can significantly enhance the server’s performance. Varnish stores web caches in the system’s memory, ensuring faster retrieval in subsequent requests for the same resource.
To get this working, follow the steps below:
Install Apache2
First, run the commands below to install the Apache webserver.
sudo apt-get update sudo apt-get install apache2
After installing Apache2, the commands below can stop, start, and enable Apache2 always to start whenever the server boots up.
sudo systemctl stop apache2.service sudo systemctl start apache2.service sudo systemctl enable apache2.service
The apache2 HTTP service is automatically bound to ports 80 and 443 for HTTPS by default. This
Install Varnish
Now that Apache2 is installed run the commands below to install Varnish
sudo apt-get install varnish
After installing Varnish, the commands below can be used to start, stop, and enable Varnish to always start up when the server boots
sudo systemctl stop varnish.service sudo systemctl start varnish.service sudo systemctl enable varnish.service
Switch the Apache default port to 8080
Since we want Varnish to listen for all traffic coming to port 80, which is Apache2’s default port, let’s configure Apache2 to use another port number. You can open the Apache default port configuration file at /etc/apache2/ports.conf and change the Listen value to 8080.
To quickly change the port, run the commands below to open the Apache default port configuration file.
sudo nano /etc/apache2/ports.conf
Then, make sure the file has these lines. Save when done.
# If you just change the port or add more ports here, you will likely also # have to change the VirtualHost statement in # /etc/apache2/sites-enabled/000-default.conf NameVirtualHost 127.0.0.1:8080 Listen 127.0.0.1:8080
Next, open the Apache default virtual host config file.
sudo nano /etc/apache2/sites-available/000-default.conf
Then, make the highlighted change below.
<VirtualHost 127.0.0.1:8080>
Save the file and exit.
Then restart Apache2
sudo systemctl restart apache2.service
To access Apache2, enter the server IP or hostname followed by port # 8080.
Configure Varnish to use Port 80
Now that port 80 is free let’s configure Varnish to use that post instead. To assign port 80 to Varnish, run the commands below.
Varnish default configure file is located at /etc/default/varnish
Open it by running the commands below:
sudo nano /etc/default/varnish
Then look for the config block under Alternative 2 and make the highlighted changes below.
## Alternative 2, Configuration with VCL
#
# Listen on port 6081, administration on localhost:6082, and forward to
# one content server selected by the vcl file, based on the request.
#
DAEMON_OPTS="-a :80 \
-T localhost:6082 \
-f /etc/varnish/default.vcl \
-S /etc/varnish/secret \
-s malloc,256m"
Save the file when you’re done.
Next, run the commands below to open the default.vcl file
sudo nano /etc/varnish/default.vcl
Then verify the line shown below is what you see.
# Default backend definition. Set this to point to your content server.
backend default {
.host = "127.0.0.1";
.port = "8080";
}
Please save the file and close it out.
After that, restart both Apache2 and Varnish.
sudo systemctl restart apache2.service sudo systemctl restart varnish.service
Next, run the commands below to start Varnish if it won’t start.
sudo /usr/sbin/varnishd -a :80 -b localhost:8080
If everything is set up correctly, Varnish should be the default listener of port 80. To test, run the commands below.
curl -I http://localhost
The results should be something like the one below
HTTP/1.1 200 OK Date: Sun, 23 Jul 2017 17:45:49 GMT Server: Apache/2.4.25 (Ubuntu) Last-Modified: Sun, 23 Jul 2017 17:01:05 GMT Vary: Accept-Encoding Content-Type: text/html X-Varnish: 10 3 Age: 9 Via: 1.1 varnish (Varnish/5.0) ETag: W/"2aa6-554ff0b3c88c9-gzip" Accept-Ranges: bytes Connection: keep-alive
Congratulations! You’ve just installed Apache2 with Varnish support.
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