Reloading the Varnish VCL
It is common to restart varnish entirely after updating the VCL, although, restarting the service looses the entire cache as well.
To reload the configuration without dropping the cache, the process is a bit more involved.
Load & Apply the VCL
export TIME=$(date +%s)
varnishadm vcl.load varnish_$TIME /etc/varnish/default.vcl
varnishadm vcl.use varnish_$TIMEList previously loaded VCLs
varnishadm vcl.list