Getting started with Varnish
Read the docsWhat is Varnish?
Varnish Cache is a downstream distribution of the Vinyl Cache open source project, delivering a stable supported LTS release with additional tooling and features on top.
The term Varnish represents the complete technology ecosystem that surrounds Varnish. This includes Varnish Cache, Varnish Enterprise, and other related tools and products that are offered by Varnish Software, and by the community at large.
How does Varnish work?
Varnish sits in front of your web server, proxies HTTP requests, and caches responses from your web server to improve performance and reduce the load on your backend servers. This is illustrated in the diagram below.
Cached objects get served from Varnish until they expire. Varnish respects the conventional HTTP headers to control caching behavior and to set the expiration time of a cached object.
Thanks to the built-in Varnish Configuration Language (VCL), you can customize caching policies to suit your specific needs.
Key features
Varnish has a rich set of features and capabilities, which you can read about in the documentation.
Extremely fast and scalable
Varnish Cache is free and open source software
Follows HTTP caching conventions
Built-in VCL programming language
Extensive metrics and logs for complete observability
Dynamic Backend with SSL support
More to come soon...
Getting started with Varnish
Varnish is available on various platforms, and can be installed using Docker or using packages for various DEB-based and RPM-based Linux distributions.
Pull in the Docker image:
docker pull varnish
Run the Docker container with the standard configuration:
docker run --rm -p 80:80 --name varnish varnish
Run the Docker container with a custom VCL file:
docker run --rm -p 80:80 --name varnish -v $(pwd)/default.vcl:/etc/varnish/default.vcl:ro varnish
Mounts default.vcl into the Docker container to customize the caching policies of Varnish. Makes a Varnish available on port 80 of your local machine.
Customize the VCL:
vcl 4.1;
backend default {
.host = "origin.example.com";
.port = "80";
}
This VCL change configures the backend server for Varnish to forward requests to origin.example.com on port 80. Use the -v $(pwd)/default.vcl:/etc/varnish/default.vcl:ro option in Docker to mount the default.vcl file and customize the caching policies of Varnish.
Learn more about deploying Varnish with Docker by reading the install guide.
Install guideInstall the Helm chart:
helm install varnish -f values.yaml oci://docker.io/varnish/varnish-cache
Customize the values.yaml file to configure the Varnish Helm chart.
Run kubectl get svc varnish-varnish-cache to get the cluster IP address and node port of the Varnish Cache service. Other service types and Ingress are also supported.
Learn more about deploying Varnish on Kubernetes by reading the install guide.
Install guideUpdate the package list:
sudo apt-get update
Configure the package registry to install Orca on Debian and Ubuntu Linux servers:
curl -Ls https://packages.varnish-software.com/varnish/bootstrap-deb.sh | sh
Install Varnish:
sudo apt-get install -y varnish
Edit the varnish systemd service:
sudo systemctl edit --full varnish
Change the port number and cache size in the varnish.service systemd parameters:
ExecStart=/usr/sbin/varnishd \
-a :80 \
-a localhost:8443,PROXY \
-f /etc/varnish/default.vcl \
-P %t/%N/varnishd.pid \
-p feature=+http2 \
-s malloc,2g
This systemd configuration change sets the Varnish service to listen on port 80, and allocates 2GB of memory for caching.
Open the VCL file:
sudo vim /etc/varnish/default.vcl
Customize the VCL:
vcl 4.1;
backend default {
.host = "origin.example.com";
.port = "80";
}
This VCL change configures the backend server for Varnish to forward requests to origin.example.com on port 80.
Restart Varnish to activate the changes:
sudo systemctl restart varnish
Learn more about installing Varnish on Debian or Ubuntu by reading the install guide.
Install guideConfigure the package registry to install Orca on Debian and Ubuntu Linux servers:
curl -s https://packages.varnish-software.com/varnish/bootstrap-rpm.sh | sh
Install Varnish:
sudo yum install -y varnish
Edit the varnish systemd service:
sudo systemctl edit --full varnish
Change the port number and cache size in the varnish.service systemd parameters:
ExecStart=/usr/sbin/varnishd \
-a :80 \
-a localhost:8443,PROXY \
-f /etc/varnish/default.vcl \
-P %t/%N/varnishd.pid \
-p feature=+http2 \
-s malloc,2g
This systemd configuration change sets the Varnish service to listen on port 80, and allocates 2GB of memory for caching.
Open the VCL file:
sudo vim /etc/varnish/default.vcl
Customize the VCL:
vcl 4.1;
backend default {
.host = "origin.example.com";
.port = "80";
}
This VCL change configures the backend server for Varnish to forward requests to origin.example.com on port 80.
Restart Varnish to activate the changes:
sudo systemctl restart varnish
Learn more about installing Varnish on Red Hat Linux and other compatible distributions by reading the install guide.
Install guideGetting help
If you need help with Varnish and the docs give you no clue on what to do there are several options available to you.
Discord Channel
While newer and less populated than the IRC channel, the Varnish discord server is also a good place to ask questions about configuration, HTTP, vmods or anything that’s even remotely related to Varnish.
StackOverflow
You can ask questions and find answers about Varnish and VCL on StackOverflow using the varnish or the varnish-vcl tag.
Social Media
There is a Varnish Cache group on LinkedIn where you can ask and answer questions.
We are also available on X as @varnishcache
Commercial support
If you need more hands-on assistance, or specialized advice, commercial support options are available through Varnish Software, the company behind Varnish.