Varnish 4 container with a confd template that outputs a nice Drupal-compatible VCL
The hostname that Varnish uses for its backend. It defaults to 'www'.
In a Dockerfile:
ENV VARNISH_BACKEND_HOST www
Via Docker Compose file:
environment: VARNISH_BACKEND_HOST: www
The port to which Varnish connects to for its backend. It defaults to '80'.