Simple routing policy is the most basic routing policy available in Amazon Route 53, AWS's scalable Domain Name System (DNS) web service. This policy is ideal for scenarios where you have a single resource that performs a specific function for your domain, such as a web server serving content for y…Simple routing policy is the most basic routing policy available in Amazon Route 53, AWS's scalable Domain Name System (DNS) web service. This policy is ideal for scenarios where you have a single resource that performs a specific function for your domain, such as a web server serving content for your website.
When you configure a simple routing policy, Route 53 responds to DNS queries based solely on the values contained in your resource record set. If you have a single record with one value, Route 53 returns that value to the requester. However, if you configure multiple values in a single record, Route 53 returns all values to the recursive resolver in random order, and the client typically uses the first value returned.
Key characteristics of simple routing policy include:
1. **No Health Checks**: Simple routing does not support health checks. Route 53 will return the configured values regardless of whether the associated resources are healthy or available.
2. **Single Resource Focus**: This policy works best when directing traffic to a single resource, though multiple IP addresses can be specified in one record.
3. **Random Selection**: When multiple values exist, the order returned is randomized, providing basic load distribution but not true load balancing.
4. **Cost-Effective**: Simple routing is straightforward to configure and does not incur additional costs beyond standard Route 53 pricing.
5. **Use Cases**: Ideal for development environments, simple websites, or scenarios where high availability is not critical.
For production environments requiring failover capabilities, geographic routing, or latency-based routing, other Route 53 policies such as weighted, failover, geolocation, or latency routing policies would be more appropriate. Simple routing serves as an excellent starting point for basic DNS configurations before implementing more complex routing strategies.
Simple routing policy is the foundational routing configuration in Amazon Route 53 and is essential knowledge for the AWS SysOps Administrator Associate exam. Understanding this policy is crucial because it serves as the baseline for comparing more complex routing policies. As a SysOps Administrator, you'll frequently configure DNS routing, and simple routing is often the starting point for many applications.
What is Simple Routing Policy?
Simple routing policy is the default routing policy in Amazon Route 53. It is used when you have a single resource that performs a given function for your domain. For example, a web server that serves content for your website.
Key Characteristics: - Routes traffic to a single resource - Cannot attach health checks to a simple routing record - If multiple values are specified, Route 53 returns all values to the client in random order - The client then chooses a value and uses it to connect - Most basic and straightforward routing option
How Simple Routing Policy Works
1. Single Value Response: When configured with one IP address or endpoint, Route 53 responds to DNS queries with that single value consistently.
2. Multiple Values Response: When you specify multiple values (up to 8 IP addresses) in the same record, Route 53 returns all values to the resolver. The client-side resolver typically uses one of these values randomly.
3. No Health Checking: Unlike other routing policies, simple routing does not support health checks. This means traffic can be routed to unhealthy resources.
4. DNS Resolution Process: - User requests your domain name - Route 53 receives the query - Route 53 returns the configured value(s) - Client connects to the returned address
When to Use Simple Routing
- Single server or resource deployments - Development and testing environments - Simple applications with no failover requirements - When you need basic DNS resolution for cost efficiency - Scenarios where client-side load balancing is acceptable
Limitations of Simple Routing
- No health checks support - No intelligent traffic routing - Cannot implement failover scenarios - Limited control over traffic distribution - All values returned have equal weight
Exam Tips: Answering Questions on Simple Routing Policy
Tip 1: Remember the Health Check Limitation When exam questions mention needing health checks or failover capabilities, simple routing is NOT the correct answer. Choose weighted, failover, or latency-based routing instead.
Tip 2: Identify Single Resource Scenarios If the question describes a single web server, single endpoint, or basic DNS needs with no redundancy requirements, simple routing is likely the answer.
Tip 3: Understand Multiple Value Behavior Know that when multiple values exist in a simple routing record, ALL values are returned to the client. The client makes the selection, not Route 53.
Tip 4: Cost Considerations Simple routing is the most cost-effective option. If a question emphasizes minimal cost and basic requirements, consider simple routing.
Tip 5: Compare with Other Policies Be prepared for questions that ask you to differentiate: - Simple vs Weighted: Weighted allows proportional traffic distribution - Simple vs Failover: Failover requires health checks and provides redundancy - Simple vs Latency: Latency routes based on lowest network latency
Tip 6: Watch for Trick Questions Questions may try to confuse you by describing a simple scenario but asking for features that require other policies. Always match the requirements to the policy capabilities.
Tip 7: Default Behavior Recognition Remember that simple routing is the DEFAULT policy. If a question mentions default behavior or basic DNS setup, think simple routing first.
Common Exam Question Patterns
- Scenarios asking for the simplest or most basic routing solution - Questions about routing to a single EC2 instance or Elastic Load Balancer - Comparison questions between different routing policies - Questions where health checks are mentioned as NOT required - Cost optimization scenarios with basic DNS needs