The DNS server also does not consider where the user is located in relation to the server that they are accessing. The user could be accessing a server on the other side of the world rather than a local server. When multiple DNS records exist on the same host name, the DNS server will respond back with a host name that is in the same network as the client when possible. In some cases there may be multiple DNS records in the same network as the client. If round robin is also enabled, the DNS records will be cycled through that are on that network.
Demonstration This demonstration will look at how to enable and disabled round robin and netmask ordering as well as how to create DNS records to use with round robin and netmask ordering. To make changes to the DNS server settings for round robin and netmask ordering, open server manager and from the tools menu select the option DNS.
To create a second, third, etc. DNS record of the same name keep repeating the procedure using the same name. CName cannot be used for only round robin records. In this example, the following DNS records were created. Log in to comment. Red Hat Guru points. David Powles. Here are the common uses of Markdown. Learn more Close. Are you sure you want to update a translation? In terms of IT system-design, this kind of structure is referred to as high-availability.
You can connect a Floating IP, which is a publicly-accessible static IP address that can be mapped to one of your Droplets, to your redundant infrastructure and launch your site or service with a single public IP. This Floating IP can be instantly remapped to a new droplet, to allow for flexibility and responsiveness in your infrastructure. Read more about this new feature here. Simply put, highly available application deployment structure, as we have just covered, depends on delivery and response to clients from different datacentres.
Although there are a number of possible ways to obtain this kind of structure, probably the simplest and the most affordable one is to take advantage of how DNS works. When a user types the domain name of a website, through a set of defined rules i. Once it receives the IP address, then it sends the request to that computer, along with some additional data, and renders the response. Since DNS allow multiple records to be kept even the same kind , it becomes possible to list multiple hosts as the server.
Things might look a little bit complex at a first glance. When a web-browser requests a web-site, it will try these IP addresses one-by-one, until it gets a response. These reverse-proxies need to be balancing the load between multiple servers at multiple locations. If a data-centre is down and the web-browser is unable to get a response from an IP address i. Since it is very unlikely for both data-centres to be unreachable at the same time, the second load-balancer will return a response.
Note: This tutorial is programming language or web-server type agnostic. Following these instructions, you can achieve high-availability regardless of your choice of frameworks, web or HTTP servers.
The first step to high-availability is to set up two or more load-balancing reverse proxies which are going to communicate between your application servers. DNS A Records translate domain names e. Click DNS on the left-hand menu and add a new domain name pointing to a load-balancer droplet from the previous step.
For global distribution to work, just like the first load-balancing servers you have created, you need two new droplets to host your application servers.
0コメント