See the Using Docker.io for content caching blog post for more details on usage.
SSH Key file
authorized_keys should also be replaced to use your own keys
To generate a keypair:
ssh-keygen -t rsa
Then copy the public key to authorized_keys
cp id_rsa.pub authorized_keys
custom.vcl can be modified to work with different server IPs etc.
supervisord.conf may be used to run varnishlog (or varnishncsa)