Route 53 Routing Policy

Routing policy is a set of rules used by domain name system (DNS) services, such as AWS Route 53, to route traffic to an application’s endpoints. It helps control how DNS service responds to DNS queries, based on factors such as the geographic location of the user, the health of resources, or the latency of the network.

Route 53 supports several routing policies, including simple routing policy, weighted routing policy, latency-based routing policy, geolocation routing policy, failover routing policy, and multi-value answer routing policy. By applying routing policies, users can optimize the performance, availability, and cost-effectiveness of their applications by directing traffic to the most appropriate resources.

Route 53 routing policy is a set of rules used by AWS Route 53, a domain name system (DNS) service, to route traffic to an application’s endpoints. Route 53 offers several routing policies, which include:

1. 1. 1. Simple routing policy: This policy is used when there is a single resource that performs a given function for a domain name. Route 53 responds to DNS queries with the IP address of the resource.       Here’s an example of how to configure a simple routing policy in Route 53:

         { 
          "Comment": "Simple routing policy example", 
           "Changes": [
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 300,
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.1"
                   }
                 ]
               }
             }
           ] }
         

         In this example, we are configuring a simple routing policy for the domain name example.com. We have one resource associated with this domain name, which is an IP address 10.0.0.1. When a DNS query is received for example.com, Route 53 will respond with the IP address 10.0.0.1.

      2. Weighted routing policy: This policy allows users to distribute traffic across multiple resources based on a weight that is assigned to each resource. This enables users to control the proportion of traffic that is sent to each resource. Here’s a code example that demonstrates how to configure a weighted routing policy in Route 53:

         {
           "Comment": "Weighted routing policy example",
           "Changes": [
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "SetIdentifier": "primary",
                 "Weight": 80,
                 "TTL": 300,
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.1"
                   }
                 ]
               }
             },
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "SetIdentifier": "secondary",
                 "Weight": 20,
                 "TTL": 300,
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.2"
                   }
                 ]
               }
             }
           ]
         }
         

         In this example, we are configuring a weighted routing policy for the domain name example.com. We have two resources associated with this domain name, each with a weight assigned to them. The first resource with the IP address 10.0.0.1 has a weight of 80, while the second resource with the IP address 10.0.0.2 has a weight of 20. This means that 80% of the traffic will be routed to the first resource, while 20% of the traffic will be routed to the second resource.

      3. Latency-based routing policy: This policy allows users to route traffic to the AWS region that provides the lowest latency to the user, based on their geographic location.is used to direct traffic to the resource that provides the best latency for the end user. Here’s an example of how to configure a latency routing policy in Route 53:

         {
           "Comment": "Latency routing policy example",
           "Changes": [
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 300,
                 "SetIdentifier": "us-west-2",
                 "Region": "us-west-2",
                 "Latency": 50,
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.1"
                   }
                 ]
               }
             },
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 300,
                 "SetIdentifier": "us-east-1",
                 "Region": "us-east-1",
                 "Latency": 75,
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.2"
                   }
                 ]
               }
             }
           ]
         }
         

         In this example, we are configuring a latency routing policy for the domain name example.com. We have two resources associated with this domain name, one in the us-west-2 region with an IP address of 10.0.0.1, and one in the us-east-1 region with an IP address of 10.0.0.2. Each resource has a latency value assigned to it based on its geographical distance from the end user. The lower the latency value, the better the performance for the end user.

         When a DNS query is received for example.com, Route 53 will evaluate the latency of each resource and direct traffic to the resource with the lowest latency. This ensures that the end user is directed to the resource that provides the best performance.

      4. Geolocation routing policy: This policy allows users to route traffic based on the geographic location of the user, such as the country, state, or city. It is used to direct traffic based on the geographical location of the end user. Here’s an example of how to configure a geolocation routing policy in Route 53:

         {
           "Comment": "Geolocation routing policy example",
           "Changes": [
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 300,
                 "SetIdentifier": "us-east-1",
                 "Region": "us-east-1",
                 "GeoLocation": {
                   "ContinentCode": "NA",
                   "CountryCode": "US",
                   "SubdivisionCode": "NY"
                 },
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.1"
                   }
                 ]
               }
             },
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 300,
                 "SetIdentifier": "eu-west-1",
                 "Region": "eu-west-1",
                 "GeoLocation": {
                   "ContinentCode": "EU",
                   "CountryCode": "GB"
                 },
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.2"
                   }
                 ]
               }
             }
           ]
         }
         

         In this example, we are configuring a geolocation routing policy for the domain name example.com. We have two resources associated with this domain name, one in the us-east-1 region with an IP address of 10.0.0.1, and one in the eu-west-1 region with an IP address of 10.0.0.2. Each resource is associated with a specific geographic location, specified by the continent code, country code, and subdivision code (if applicable).

         When a DNS query is received for example.com, Route 53 will evaluate the geographic location of the end user based on their IP address and direct traffic to the resource associated with that location. This ensures that the end user is directed to the resource that provides the best performance and compliance with local regulations.

      5. Failover routing policy: This policy enables users to route traffic to a secondary resource if the primary resource becomes unavailable.It is used to direct traffic to a secondary resource if the primary resource becomes unavailable. Here’s an example of how to configure a failover routing policy in Route 53:

         {
           "Comment": "Failover routing policy example",
           "Changes": [
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 300,
                 "SetIdentifier": "primary",
                 "Failover": "PRIMARY",
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.1"
                   }
                 ]
               }
             },
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 300,
                 "SetIdentifier": "secondary",
                 "Failover": "SECONDARY",
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.2"
                   }
                 ]
               }
             }
           ]
         }
         

         In this example, we are configuring a failover routing policy for the domain name example.com. We have two resources associated with this domain name, one primary resource with an IP address of 10.0.0.1, and one secondary resource with an IP address of 10.0.0.2. Each resource is associated with a specific set identifier and failover configuration.

         When a DNS query is received for example.com, Route 53 will first direct traffic to the primary resource (10.0.0.1). If the primary resource becomes unavailable, Route 53 will automatically failover to the secondary resource (10.0.0.2) and direct traffic there.

      6. Multi-value answer routing policy: This policy enables users to return multiple IP addresses for a DNS query, which can help improve the availability of an application. Itis used to respond to DNS queries with multiple values for the same resource record set. Here’s an example of how to configure a multi-value answer routing policy in Route 53:

         {
           "Comment": "Multi-value answer routing policy example",
           "Changes": [
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 60,
                 "SetIdentifier": "server1",
                 "MultiValueAnswer": true,
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.1"
                   },
                   {
                     "Value": "10.0.0.2"
                   }
                 ]
               }
             },
             {
               "Action": "CREATE",
               "ResourceRecordSet": {
                 "Name": "example.com.",
                 "Type": "A",
                 "TTL": 60,
                 "SetIdentifier": "server2",
                 "MultiValueAnswer": true,
                 "ResourceRecords": [
                   {
                     "Value": "10.0.0.3"
                   },
                   {
                     "Value": "10.0.0.4"
                   }
                 ]
               }
             }
           ]
         }
         

         In this example, we are configuring a multi-value answer routing policy for the domain name example.com. We have two sets of resources associated with this domain name, each containing two IP addresses.

         When a DNS query is received for example.com, Route 53 will randomly select one of the resource sets and return both IP addresses in the response. This can be useful for load balancing traffic across multiple resources and improving overall availability and performance.

By using routing policies, users can optimize the performance, availability, and cost-effectiveness of their applications by directing traffic to the most appropriate resources.