What a load balancer does, and its limits today
A load balancer takes traffic arriving on one address and shares it between several of your servers. If one stops answering, it stops sending traffic there.
Read this before you order: internal traffic only
A load balancer does not have an address on the internet yet. Its address is on your own private network, so it can only be reached from your other servers there. It cannot take traffic from visitors on the internet directly.
So today it suits traffic between your own servers, for example application servers in front of several database or API servers. If you need to balance traffic from the internet, talk to us before ordering rather than after. The order page says when this changes.
Listeners and servers
Open Load Balancers and choose yours. Its Address is shown at the top.
- A listener is a protocol and port the load balancer accepts traffic on: TCP, HTTP, HTTPS or UDP, on any port from 1 to 65535. HTTPS is passed through unchanged, so your servers keep their own certificates.
- Each listener has a pool of servers to send traffic to. Add a server by its IP address and port. It must be one of your own servers.
The number of listeners, and of servers per listener, depends on your plan. If you run out, remove one or ask us about a bigger plan.
You can choose how traffic is shared (round robin, least connections or by source address) when you order. Listeners you add later use round robin.
SSH (port 22) and RDP (port 3389) cannot be balanced: you would reach a different machine each time you connected. Connect to those servers directly.
Health checks
Every listener checks its servers every 5 seconds. A server starts receiving
traffic once it passes, and traffic stops going to a server that keeps failing.
HTTP listeners request /; HTTPS listeners check that a secure connection
opens; TCP and UDP listeners check that the port answers.
Changing or cancelling
Changes are refused while the load balancer says it is working on something. Try again a moment later. To cancel a load balancer, ask us.