Amazon Route 53 offers several routing policies that determine how DNS queries are answered, enabling sophisticated traffic management for your applications.
**Simple Routing** is the default policy, directing traffic to a single resource. It returns all values in random order if multiple records …Amazon Route 53 offers several routing policies that determine how DNS queries are answered, enabling sophisticated traffic management for your applications.
**Simple Routing** is the default policy, directing traffic to a single resource. It returns all values in random order if multiple records exist.
**Weighted Routing** allows you to distribute traffic across multiple resources based on assigned weights. For example, assigning weights of 70 and 30 sends 70% of traffic to one resource and 30% to another. This is ideal for blue-green deployments or testing new application versions.
**Latency-based Routing** directs users to the AWS region providing the lowest latency. Route 53 measures latency between users and regions, routing traffic to the fastest endpoint for optimal user experience.
**Failover Routing** implements active-passive failover configurations. When health checks detect the primary resource is unhealthy, traffic automatically routes to the secondary standby resource, ensuring high availability.
**Geolocation Routing** routes traffic based on the geographic location of users. You can specify routing for continents, countries, or US states, useful for content localization or compliance with regional regulations.
**Geoproximity Routing** (Traffic Flow only) routes based on geographic location of resources and users, with the ability to shift traffic using bias values. Increasing bias expands the geographic area from which resources receive traffic.
**Multivalue Answer Routing** returns multiple healthy records (up to eight) for DNS queries. Each record includes a health check, providing a simple form of load balancing and improved availability.
**IP-based Routing** routes traffic based on the originating IP address of clients, allowing you to optimize costs or improve performance for specific user groups.
Health checks can be associated with most routing policies to ensure traffic only reaches healthy endpoints, enhancing application reliability and user experience.
Route 53 Routing Policies - Complete Guide
Why Route 53 Routing Policies Are Important
Route 53 routing policies are fundamental to AWS networking and are heavily tested on the SysOps Administrator Associate exam. They determine how DNS queries are answered, enabling you to build highly available, fault-tolerant, and geographically optimized applications. Understanding these policies is essential for designing resilient architectures and troubleshooting DNS-related issues in production environments.
What Are Route 53 Routing Policies?
Route 53 routing policies are rules that define how Amazon Route 53 responds to DNS queries. Each policy serves a specific use case:
1. Simple Routing Policy Routes traffic to a single resource. If multiple values are specified, Route 53 returns all values in random order. No health checks are associated with individual records.
2. Weighted Routing Policy Distributes traffic across multiple resources based on assigned weights (0-255). Useful for load balancing and testing new application versions. A weight of 0 stops traffic to that resource.
3. Latency-Based Routing Policy Routes traffic to the resource that provides the lowest latency for the user. Route 53 measures latency between users and AWS regions to make routing decisions.
4. Failover Routing Policy Creates active-passive failover configurations. Traffic goes to the primary resource unless it fails health checks, then routes to the secondary resource.
5. Geolocation Routing Policy Routes traffic based on the geographic location of users. You can specify routing by continent, country, or US state. A default record handles queries from unspecified locations.
6. Geoproximity Routing Policy Routes traffic based on the geographic location of resources and optionally shifts traffic using bias values. Requires Route 53 Traffic Flow. Bias values range from -99 to +99.
7. Multivalue Answer Routing Policy Returns multiple healthy records (up to 8) in response to DNS queries. Each record can have an associated health check, providing a form of client-side load balancing.
8. IP-Based Routing Policy Routes traffic based on the IP address of the client. You create CIDR collections and map them to specific endpoints.
How Route 53 Routing Policies Work
When a DNS query is made: 1. Route 53 receives the query at one of its edge locations 2. The routing policy logic is applied based on the record configuration 3. Health checks are evaluated (if configured) 4. The appropriate IP address or values are returned to the client 5. The client connects to the returned endpoint
Health checks play a crucial role in most routing policies, enabling automatic failover when resources become unhealthy.
Exam Tips: Answering Questions on Route 53 Routing Policies
Key Scenarios to Remember:
• Testing new application versions → Weighted Routing (use small weight for new version) • Active-passive disaster recovery → Failover Routing • Serve content based on user location → Geolocation Routing • Lowest response time for users → Latency-Based Routing • Simple single-resource setup → Simple Routing • Multiple healthy endpoints with health checks → Multivalue Answer Routing • Shift traffic between regions with fine control → Geoproximity with Traffic Flow
Common Exam Traps:
• Simple routing does NOT support health checks on individual records • Geolocation requires a default record for users not matching any location • Weighted routing with weight 0 means no traffic (useful for maintenance) • Latency-based routing measures latency to AWS regions, not to your actual servers • Multivalue answer is NOT a replacement for load balancers • Geoproximity requires Traffic Flow and is the only policy that uses bias
Health Check Considerations:
• Health checks can monitor endpoints, other health checks, or CloudWatch alarms • String matching health checks examine the first 5120 bytes of the response • Health check intervals can be 10 or 30 seconds • Fast health checks (10 seconds) cost more
When Reading Exam Questions:
Look for keywords like: lowest latency, geographic restrictions, blue-green deployment, disaster recovery, compliance requirements, percentage of traffic, and user location to identify the correct routing policy.