Poc Dns Load Balancing

The purpose of this proof of concept is to investigate and determine a strategy to load balance web server geographically via DNS entries. In essence, given a dns entry “upstestgeo”, the users will hit the server closest to their location.

Scope

We are limiting ourselves at the web server level. Synchronization of data if necessary is another story.

Setup

With the help of a Linux Administrator, we setup the DNS map for the follow servers.

BUC: 10.18.1.68 MTL: 10.129.9.20 DNS: http://upstestgeo

Results

The command “ping upstestgeo” was run on the following computer in the following location.

Montreal

Pinging [10.129.9.20] with 32 bytes of data:
Reply from 10.129.9.20: bytes=32 time<1ms TTL=124
Reply from 10.129.9.20: bytes=32 time<1ms TTL=124
Reply from 10.129.9.20: bytes=32 time=3ms TTL=124
Reply from 10.129.9.20: bytes=32 time<1ms TTL=124

Bucharest

Pinging [10.18.1.68] with 32 bytes of data:
Reply from 10.18.1.68: bytes=32 time<1ms TTL=128
Reply from 10.18.1.68: bytes=32 time<1ms TTL=128
Reply from 10.18.1.68: bytes=32 time<1ms TTL=128
Reply from 10.18.1.68: bytes=32 time<1ms TTL=128

Shanghai

Pinging [10.129.9.20] with 32 bytes of data:
Reply from 10.129.9.20: bytes=32 time=249ms TTL=121
Reply from 10.129.9.20: bytes=32 time=249ms TTL=121
Reply from 10.129.9.20: bytes=32 time=249ms TTL=121
Reply from 10.129.9.20: bytes=32 time=249ms TTL=121

Kiev

Pinging [10.18.1.68] with 32 bytes of data:
Reply from 10.18.1.68: bytes=32 time=81ms TTL=125
Reply from 10.18.1.68: bytes=32 time=80ms TTL=125
Reply from 10.18.1.68: bytes=32 time=80ms TTL=125
Reply from 10.18.1.68: bytes=32 time=80ms TTL=125

Conclusion

Global server load balancing via DNS is possible. It is possible to deploy a service in different datacenter to reduce latency for clients. As seen above, the closest server is pinged in accordance to the DNS mapping.