Create an IPVS Load Balancer from a list of 'real servers' in a TXT record.
My initial motivation is for a Kubernetes control plane - and not use an external load balancer for the API servers, which means they can stay behind a firewall and not on the public internet, and no separate load balancing server is required; they just need to be able to make a DNS query to obtain a list of peers (to whom they already have access over a private network).
In general, this could be useful in any case where:
- you have a set of machines on a common network
- each machine needs to talk to one of the others, but it doesn't matter which
- you don't want a separate load balancer
- you can query a DNS record from the machines, and keep it up to date with the machine list from outside (e.g. CI/CD)
- Install
ipvsadm - Put
ipvs-txt-lbsomewhere that's in$PATH - Put
ipvs-txt-lb.servicein/etc/systemd/system/and runsystemctl enable ipvs-txt-lb - Put
ipvs-txt-lb.confin/etc/and populate it - Populate your
TXTrecord with a;-delimited list of servers, e.g.alpha;beta - Run
systemctl start ipvs-txt-lb