Skip to content
Devilbox

Enable and configure Varnish

Enable and configure Varnish

Varnish adds an HTTP cache in front of Devilbox projects. The maintained override also includes HAProxy so you can put HTTPS offloading in front of Varnish when needed.

How it works

Devilbox keeps optional integrations as override snippets in the compose/ directory. To enable Varnish, copy its snippet into the project root as docker-compose.override.yml, then start the stack.

Enable

Terminal window
cp compose/docker-compose.override.yml-varnish docker-compose.override.yml
./dvl.sh up

Configuration

The snippet defines two services:

ServiceImageHost portsPurpose
varnishdevilbox/varnish:${VARNISH_SERVER:-6}-0.3${HOST_PORT_VARNISH:-6081}:6081HTTP cache in front of httpd:80.
haproxydevilbox/haproxy:0.3${HOST_PORT_HAPROXY:-8080}:80, ${HOST_PORT_HAPROXY_SSL:-8443}:443Optional frontend for Varnish with SSL offloading.

The Varnish service mounts ${DEVILBOX_PATH}/cfg/varnish-${VARNISH_SERVER:-6}:/etc/varnish.d. HAProxy mounts the Devilbox CA and HTTPD data directory.

VariableDefaultPurpose
VARNISH_SERVER6Varnish image/config directory version.
HOST_PORT_VARNISH6081Host port for Varnish.
VARNISH_CONFIG/etc/varnish/default.vclVCL file used by Varnish.
VARNISH_CACHE_SIZE128mCache size.
VARNISH_PARAMS-p default_ttl=3600 -p default_grace=3600Extra varnishd parameters.
HOST_PORT_HAPROXY8080Host HTTP port for HAProxy.
HOST_PORT_HAPROXY_SSL8443Host HTTPS port for HAProxy.

Usage

Warm a project URL through Varnish:

Terminal window
curl -I http://localhost:6081/

Watch Varnish logs while making requests:

Terminal window
docker compose logs -f varnish

Use HAProxy in front of Varnish for HTTPS offloading:

Terminal window
curl -kI https://localhost:8443/

Place custom VCL files in cfg/varnish-6/ and point VARNISH_CONFIG at the file inside /etc/varnish.d/.

Disable

Terminal window
./dvl.sh down
rm docker-compose.override.yml
./dvl.sh up

Troubleshooting

  • If Varnish returns backend errors, verify the VCL backend points to host httpd on port 80.
  • If custom VCL is ignored, confirm it is under the mounted cfg/varnish-${VARNISH_SERVER} directory and VARNISH_CONFIG uses the container path.
  • If host ports conflict, adjust HOST_PORT_VARNISH, HOST_PORT_HAPROXY, or HOST_PORT_HAPROXY_SSL.

See also