High-Availability IoT Cluster Demo
(Interactive SMQ Example & Tutorial)
The following article and interactive demo shows how to set up a very cost effective High-Availability Internet of Things Cluster. A High-Availability (HA) cluster may use a load-balancer and/or use DNS, or other technologies such as Anycast. In this article and demo, we use a load-balancer-less solution based purely on DNS -- a so called DNS Round-Robin setup.
Round Robin DNS provides a low cost alternative to traditional cloud services. We recommend reading the DZone article Cheaper Alternatives to IoT Cloud Services if you are new to Round Robin DNS.
We have selected a low cost Virtual Private Server (VPS) provider for our example, and we have the two servers located in Portland and Los Angeles. The geographical dispersion provides strong redundancy. The yearly lease for each server is $12, thus the total cost for our example cluster is $24 per year.
We have two html frames below, and each html frame opens the SMQ IoT LED example on a separate server. The domain name simplemq.com translates to two IP addresses (two online servers) and you randomly get one of these IP addresses when navigating to simplemq.com. However, we have also configured the DNS such that you can navigate directly to a specific cluster node.
Notice that clicking a button in any frame window below is synchronized two windows. Not only does the SMQ protocol provide synchronization between multiple HTML5 clients, SMQ also automatically synchronizes between the servers in the cluster.
Before clicking any of the LED buttons below, make sure to select the same device in each window. You do this by clicking the same IP address in the left pane for each window below.