varnish daemon not listening on configured port

Solution 1:

You need to change the varnish start parameters in the systemd service definition as well. You could edit the line starting with ExecStart in the service defintion file:

sudo vi /lib/systemd/system/varnish.service

Modifying this file however, has the disadvantage that it will not be updated in future updates of the package. Alternatively, as suggested in the comments, you could create a systemd drop in file, which is the preferred way of adding settings to systemd definitions.

# create the drop in directory
sudo mkdir /etc/systemd/system/varnish.service.d
# create the drop in file. The name is irrelevant, as long as it ends in .conf
sudo vi /etc/systemd/system/varnish.service.d/mysettings.conf

Here you only need to add the settings you want do change, everything else will be loaded from the default definition file.

Example:

[Service]
ExecStart=/usr/sbin/varnishd -j unix,user=vcache -F -a :80 -T localhost:6082 -f /etc/varnish/default.vcl -S /etc/varnish/secret -s malloc,256m

_{This is the default line, change it as you need}

Afterwards, tell systemctl to reload it's config files and to restart the service

sudo systemctl daemon-reload
sudo service varnish restart

Varnish should now listen on port 80.

Solution 2:

Note that the drop-in should have an empty ExecStart= Otherwise you will get an error starting the service (duplicate ExecStart)

sudo mkdir /etc/systemd/system/varnish.service.d
sudo nano /etc/systemd/system/varnish.service.d/varnishd.conf

With

[Service]
ExecStart=
ExecStart=/usr/sbin/varnishd -j unix,user=vcache -F -a :80 -T <YOUR WEBSERVER IP>:8081 -f /etc/varnish/default.vcl -S /etc/varnish/secret -s malloc,256m