AWS ROUTE53 - Routing Policies
When you create a Record, you choose a routing policy, which determines how Amazon Route53 responds to Queries
There are 7 types of Routing Policies Available in Route53
Simple Routing (Default)
Failover Routing
Geo-Location Routing
Multi-Value Answer Routing
Latency Based Routing
Weighted Routing
Geo-Proximity Routing
Let's Discuss Furthermore above policies
Failover Routing Policy:-
Failover Routing lets you route traffic to a resource when the resource is healthy. If the main resource is not healthy, then route traffic to a different resource.
The primary and secondary records can route traffic to anything from an Amazon S3 bucket that is configured as a website to a complex tree of Records.
A Failover Routing policy is applicable for the Public hosted Zone only.
Geolocation Routing:-
Geolocation routing lets you choose the resources that serve your traffic based on the geographic location of your users. i.e. the location that DNS Queries Originate from. e.g. You may have a presence in Europe and Asia. Now, you want users in Asia to be served in Asia and those in Europe to be served by servers in Europe.
The benefits are as below:-
You can localize your content and present some or all of your website in the language of your users.
You can also use geolocation Routing to Restrict the distribution of Content to only the locations in which you have distribution rights.
You can specify geographic locations by continent, country, or state in the United States
If you create separate records for overlapping geographic regions. e.g. one record for North America and one for Canada- priority goes to the smallest geographic region.
Geolocation works by mapping IP addresses to locations. However, some IP addresses are not mapped to geographic locations.
Latency Based Routing:-
If your application is hosted in multiple Amazon EC2 Regions, you can improve performance for your users by serving their requests from the Amazon EC2 region that provides the lowest latency.
To use latency-based routing, you create latency records for your resources in multiple EC2 regions.
When Amazon Route53 receives a DNS Query for your domain or subdomain
- It determines which Amazon region you have created a latency record for.
- Determine which regions give the lowest latency to users.
- Then select a latency record for that region.
e.g. Suppose you have ELB in US-East and in Asia Pacific (Mumbai Region).
- You created a latency record for each load Balancer.
- Here's what happens when a user in London enters the name of your domain in a browser.
- DNS routes the request to a Route53 Name server. Route53 refers to its data on latency between London and the Mumbai region and between London and North Virginia.
If latency is lower between London and North Virginia, Route53 responds to the Query with the IP address for the North Virginia Load Balancer.
Weighted Routing Policy:-
Weighted Routing Policy lets you associate multiple resources with a single domain name or subdomain name and choose how much traffic is routed to each resource.
This can be useful for a variety of purposes, including load balancing and testing new versions of Software.
Weights can be assigned any number from 1 to 255.
A weighted Routing policy can be applied when there are multiple resources that perform the same function for example -> Webserver serving the same website.
To configure weighted Routing, you can create Records that have the same name and type for each of your Resources.
Amazon Route53 sends traffic to a Resource based on the Weight that you assign to the record as a proportion of the total weight for all records in the group.
e.g. Suppose abc.com has three resource record sets with weights of 1 (20%), 1(20%), and 3 (60%) (sum=5)
On average, Route53 selects each of the first 2 resource records set one-fifth of the time and returns the third resource record set three-fifth of the time.
Geo-Proximity Routing Policy:-
It is used when you want to route traffic based on the location of your resources and optionally, shift traffic from resources in one location to resources in another. You can also optionally choose to Route more traffic or less to a given resource by specifying a value, known as a 'bias'. A 'bias' expands or shrinks the size of the geographic region from which traffic is Routed to a resource.
Multivalue Answer Routing Policy:-
- It is used when you want Route53 to respond to DNS Queries with up to eight healthy Record Selected at Random.
Multivalue answer routing lets you configure Amazon Route53 to return Multiple Values, such as IP addresses for your webservers, in response to DNS Queries. You can specify multiple values for almost any Record, but the multivalue answer routing also lets you check the health of each resource, So Route53 returns only values for healthy Resources. It's not a substitute for Load Balancer but it has the ability to return multiple health checkable IP addresses in a way to use DNS to improve availability and load balancing. For e.g.