Due to some internal issues, we need to remove unused images as soon as they become unused.
I do know it's possible to use Garbage collection but it doesn't offer strict policy as we need. I've come across this solution but
I was thinking about setting a cron job directly over the nodes to run docker prune but I hope there is a better way
No idea if it makes a difference but we are using AKS
This doesn't really accomplish much since things will be re-downloaded if they are requested again. But if you insist on a silly thing, best bet is a DaemonSet that runs with the host docker control socket hostPath-mounted in and runs docker system prune as you mentioned. You can't use a cron job so you need to write the loop yourself, probably just bash -c 'while true; do docker system prune && sleep 3600; done' or something.