Mammoth Cloud customers can purchase access to a HTTP/HTTPS load balancer for $10 per month. The load balancer is fully redundant and configurable through our control panel.
Requirements
- At least two VPS to gain high availability
- Each VPS must be running a web server such as Apache or IIS
- Each VPS must serve essentially the same content
How it works
After purchasing load balancer access, you will be assigned a new, "virtual" IP address. This will be the IP address of your web site. Using our control panel, select the VPS that HTTP requests will be distributed over - these are referred to as the "real" IPs.
The load balancer includes an automated health check - every three seconds, each of the VPS will receive a HTTP request to determine if that server is functioning correctly.
When a new HTTP request is received at the virtual IP, the load balancer will then select a healthy VPS and pass the request through. The real server then processes the request and sends a response.
Technical information
- The load balancer is non-terminating: packets from each client are passed directly to the server with no modification to the payload.
- The load balancer peforms layer-2 ("direct") forwarding: each packet from a client has the destination MAC address altered and then placed back onto the network for the real server to receive.
- From the real server's perspective, the source IP is still the client - the load balancer is invisible.
- From the real server's perspective, the destination IP is the virtual IP. For this reason the virtual IP must be added as a secondary address on each of the real servers. Our virtualisation stack will automatically block ARP on the real servers to prevent conflicts.
- The load balancer has a 60 second timeout on session stickiness (requests from one IP address will continue to be sent to the same real server within the 60 second window)
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