![]() Once the DNS changes are propagated, every new end user will be routed to a different IP address and the DNS load balancing setup is complete at that point.įor example, one client will get a response for 1.2.3.4, 1.2.3.5 and 1.2.3.6 IPs and will be routed to the first IP. For example, if requests for hostname are served by 3 different machines, each having their own IP, three separate A records for need to be set up in StackPath portal, where each A record is pointed to a different IP address of the target machines. a website or an API endpoint), the A records for the hostname in question need to be pointed to all IPs of the machines serving requests for a given web service. In order to implement DNS load balancing for a web service (e.g. Example: Setting up DNS load balancing for a web service That problem can be partially tackled by setting up lower TTL values for the DNS records, but the clients and intermediate DNS resolvers might still have old DNS records cached for extended periods of time. Once the issue is discovered, taking the machine in question out of the rotation might take a while since DNS changes are not always instantaneous. If one of the servers gets overloaded or becomes inaccessible due to a network outage, it won’t be automatically taken out of the rotation and the end users would still be routed to it since there’s no way for the DNS to know the machine is experiencing issues. DNS itself is not capable of monitoring the servers for potential load issues or any kind of network outages. While DNS based load balancing is fairly easy to set up, it comes with a few inherent drawbacks. Another advantage is the fact there is no new software to install and no additional server configuration changes to make - the traffic is routed at a DNS level. Essentially, the only thing required is multiple DNS records for the same hostname pointed to different IPs of all the machines serving requests for a given web service. That kind of setup makes different end-users routed to different machines, effectively creating a load balancing configuration at a DNS level.Īdvantages of DNS load balancing solution The main advantage of DNS load balancing is the ease of configuration. The list of IP addresses for a given DNS record is rotated on a round-robin basis. When resolving a hostname on StackPath DNS, the list of IP addresses will be returned in a different order each time the new client makes a DNS query. The main idea behind DNS based load balancing is that the client will target the first IP it receives for a given hostname. With StackPath DNS, you can load balance traffic towards your website, mail server, application, API, or any other kind of publicly accessible network. To have DNS-based load balancing, you must configure your DNS records so that different end users are routed to different servers. that I am probably drawing twice as fast from the center two belts than I am from the others, and if that is so.You can use this document to learn how to implement a DNS-based load balancer. Did I design it right to ensure that it will draw equally from the 6 belts? My instints say no. (1) The trivial balancer/compressor below takes from the 6 unloaded belts and outputs to one or two belts. So, we need an "input-balanced" balancer.Īt this point I have 2 questions, one simple and one not so simple: And yet, to ensure smooth unloading, we want to pull exactly the same number of items from each of the belts coming from the train. Most of the balancer discussion and designs available are about balancing the *output* of a set of multiple belts, and some about balancing the right and left lane of a belt.īut there is very little know-how available on balancing the consumption of items across multiple belts on the *input* side, no matter what happens on the output side and that is what this thread is about.įor example, imagine a situation where you have 6 belts coming out of unloading a wagon, but your consumption (for whatever reason) only pulls items from the 1st belt.
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