Tutorial / Cram Notes
A public hosted zone is where you configure DNS settings for a domain that is publicly accessible over the internet. Here’s how you can create a public hosted zone in Route 53:
- Log in to the AWS Management Console and open the Route 53 console.
- Choose “Hosted zones” and then click “Create Hosted Zone”.
- Enter your domain name and any optional comments.
- Select type ‘Public Hosted Zone’.
- Click “Create”.
AWS Route 53 will then provide you with a set of name servers (NS) and a start of authority (SOA) record for your new zone. You will update your domain’s NS records at your domain registrar with these values to make Route 53 the DNS service for your domain.
Example:
If your domain is “example.com”, Route 53 will give NS records like:
| Name | Type | Value |
|---|---|---|
| example.com. | NS | ns-2048.awsdns-64.com. |
| ns-1820.awsdns-36.org. | ||
| ns-1000.awsdns-61.net. | ||
| ns-1234.awsdns-22.co.uk. | ||
| example.com. | SOA | ns-2048.awsdns-64.com. aws-info.amazon.com. |
Private Hosted Zones
A private hosted zone is a container that holds information about how you want to route traffic for a domain and its subdomains within one or more VPCs. You’ll create records just like you do in a public hosted zone but the records in a private hosted zone are only visible from within the associated VPCs. Here’s how to create it:
- Open the Route 53 console and select “Hosted zones”.
- Click “Create Hosted Zone”.
- Enter your domain name and any optional comments.
- Select the type ‘Private Hosted Zone’.
- Choose the VPC and region.
- Click “Create”.
Example:
For a private domain “internal.example.com” within a VPC:
| Name | Type | Value | Routing Policy |
|---|---|---|---|
| internal.example.com. | A | IP Address of your resource | Simple |
Routing Traffic to Multiple Availability Zones
Within AWS, you can set up a private hosted zone and create DNS records that route traffic among multiple Availability Zones (AZs). For instance, a common setup is having web servers or databases in multiple AZs to avoid a single point of failure.
You will want to improve availability by using Route 53 health checks and DNS failover. By implementing these features with records for your application across multiple AZs, Route 53 will respond to DNS queries for your application using the following logic:
- If the endpoint in one AZ is healthy, Route 53 directs traffic to that AZ.
- If the endpoint in one AZ is unhealthy, Route 53 automatically reroutes traffic to a healthy endpoint in another AZ.
Example:
| Name | Type | Value | Routing Policy | Health Check |
|---|---|---|---|---|
| app.internal.example.com. | A | IP in AZ1 | Failover | Yes |
| app.internal.example.com. | A | IP in AZ2 | Failover | Yes |
When creating records, choose ‘Failover’ routing policy and associate the health checks. If the health check fails in AZ1, Route 53 will start routing to the endpoint in AZ2, where the IP resolves to a server in a different Availability Zone.
Conclusion
Designing your DNS strategy with Route 53 utilizing public hosted zones for internet-facing resources and private hosted zones for internal resources, along with health checks and failover routing, can significantly improve your application’s availability. By leveraging AWS’s global network and the proximity routing features available in Route 53, you ensure that your applications are resilient and highly available to serve your end-users efficiently.
Practice Test with Explanation
True or False: A Route 53 public hosted zone can be used to route traffic within a Virtual Private Cloud (VPC).
- (A) True
- (B) False
B (False)
A Route 53 public hosted zone is used to route traffic on the public internet. For routing traffic within a VPC, a private hosted zone is used.
Which record set type should you use to ensure high availability and load balancing across multiple Amazon EC2 instances for your domain?
- (A) A
- (B) AAAA
- (C) CNAME
- (D) Alias
D (Alias)
Alias record sets can be used to route traffic to an Elastic Load Balancer, Amazon CloudFront distribution, or an S3 bucket that is configured as a website endpoint, which in turn provide high availability and load balancing.
True or False: When you create a private hosted zone in Route 53, you need to associate it with a VPC.
- (A) True
- (B) False
A (True)
A private hosted zone must be associated with one or more VPCs to ensure that it is private and that DNS queries are routed correctly within the selected VPCs.
You can control which networks are allowed to forward DNS queries to your Amazon Route 53 private hosted zone through:
- (A) Security Groups
- (B) Network Access Control Lists (NACLs)
- (C) VPC association authorization
- (D) Route tables
C (VPC association authorization)
Route 53 private hosted zones use VPC association authorization to control which VPCs can forward DNS queries to the private hosted zone.
When creating a Route 53 record set, what is the TTL (time to live) used for?
- (A) Indicates how long an individual record should be cached by the client.
- (B) Determines the duration of the domain registration.
- (C) Specifies the interval for a health check.
- (D) Identifies the priority of the DNS record.
A (Indicates how long an individual record should be cached by the client.)
The TTL (time to live) setting in a DNS record tells the client how long to cache the resolved record before querying the DNS again for updated information.
Which statement is true regarding Alias records in Amazon Route 53?
- (A) Alias records incur additional charges for DNS queries.
- (B) Alias records can only point to Amazon S3 buckets.
- (C) Alias records can map one DNS name to another Amazon Route 53 DNS name within the same hosted zone.
- (D) Alias records do not support weighted routing policies.
C (Alias records can map one DNS name to another Amazon Route 53 DNS name within the same hosted zone.)
Alias records in Route 53 can map one DNS name to another DNS name that Route 53 manages, without incurring additional charges and are particularly useful within the same hosted zone.
True or False: You can create a Route 53 health check on an endpoint in a private hosted zone.
- (A) True
- (B) False
B (False)
Route 53 health checks are not supported for endpoints in a private hosted zone because these endpoints are not reachable from the internet, which is necessary for Route 53 health checkers.
A multi-value answer routing policy in Amazon Route 53 can be used to:
- (A) Redirect DNS queries based on the geolocation of the user.
- (B) Route traffic to multiple resources in a random order.
- (C) Prioritize DNS queries based on resource health checks.
- (D) Provide different resources when the DNS query comes from different regions.
B (Route traffic to multiple resources in a random order.)
The multi-value answer routing policy allows Route 53 to respond to DNS queries with up to eight healthy records selected at random.
True or False: When you delete a Route 53 hosted zone, all of the records in the hosted zone are also deleted.
- (A) True
- (B) False
A (True)
When you delete a hosted zone, Route 53 automatically deletes all records associated with that hosted zone.
You can associate an Amazon Route 53 private hosted zone with:
- (A) Multiple VPCs in the same region.
- (B) Multiple VPCs in different regions.
- (C) Only one VPC per hosted zone.
- (D) VPCs and traditional on-premises networks.
B (Multiple VPCs in different regions.)
Amazon Route 53 allows you to associate a private hosted zone with multiple VPCs, regardless of whether the VPCs are in the same, or different AWS Regions.
True or False: Weighted routing policies in Amazon Route 53 support different weights for records in both public and private hosted zones.
- (A) True
- (B) False
A (True)
Weighted routing policies can be applied to records in both public and private hosted zones, distributing traffic based on specified weights.
True or False: To resolve DNS names between two VPCs with associated private hosted zones, you must use VPC peering or a transit gateway.
- (A) True
- (B) False
A (True)
To resolve DNS names between two VPCs, they must be able to communicate through some networking setup such as VPC peering or a transit gateway, and the private hosted zones must be associated with both VPCs.
Interview Questions
What is the difference between a public hosted zone and a private hosted zone in AWS Route 53?
A public hosted zone in AWS Route 53 is used to define how traffic is routed on the public internet for a domain and its subdomains. It is accessible over the internet. On the other hand, a private hosted zone is used for routing traffic within one or more Amazon Virtual Private Clouds (VPCs) and is not accessible over the public internet. It allows AWS resources within a VPC to communicate with each other using domain names without exposing the DNS service to the internet.
How can you use Route 53 health checks to improve application availability?
Route 53 health checks can monitor the health and performance of your application endpoints, such as web servers and other resources. If a health check fails, Route 53 can route traffic away from the unhealthy endpoint to other operational endpoints. This improves application availability by avoiding routing to failed or underperforming resources.
What is a failover routing policy in Route 53, and how does it contribute to application availability?
The failover routing policy in Route 53 allows you to configure active-passive failover, where a primary resource takes all the traffic when healthy and automatically fails over to a secondary (backup) resource when the primary is unhealthy. This policy ensures high availability by routing user traffic to a backup site or resource in case the primary site fails or becomes unresponsive.
Explain the concept of latency-based routing in Route 53 and its role in optimizing application performance.
Latency-based routing in Route 53 allows you to route your users to the AWS region that provides the lowest possible latency. This is done by automatically routing user requests to the region providing the fastest response time. As a result, application performance is optimized as users experience reduced load times for your application or website.
Can you create both public and private hosted zones for the same domain name in Route 53? If yes, how does AWS differentiate between them?
Yes, you can create both public and private hosted zones for the same domain name in Route AWS differentiates between them based on the environment from which the DNS queries are made. Queries from the public internet are answered using the public hosted zone, while queries from within an associated Amazon VPC use the private hosted zone.
How can you use Route 53 to route traffic to multiple availability zones to enhance application availability?
You can use Route 53 to create records that are set up with a multi-value answer routing policy. When you configure this policy, Route 53 returns multiple IP addresses for a DNS query, allowing traffic to be spread across multiple availability zones. This approach enhances application availability by distributing the load and providing fault tolerance across different zones.
What are alias records in Route 53, and when would you choose them over CNAME records?
Alias records in Route 53 are a Route 53-specific feature that allows you to map domain names to AWS resources such as ELB load balancers, CloudFront distributions, or S3 buckets, without charging for the DNS queries. Unlike CNAME records, alias records can be used for the root domain (zone apex). You would choose alias records over CNAMEs when you need to map your DNS records to AWS resources, particularly for the domain apex where CNAMEs cannot be used.
Describe how you would configure split-view DNS (split-horizon DNS) in Route
To configure split-view DNS in Route 53, you would create a public hosted zone to manage DNS for users on the public internet and a private hosted zone for the same domain for users within an Amazon VPC. Each hosted zone contains its set of DNS records that resolve to different IP addresses based on whether the query originates from within the VPC (private) or from the public internet (public).
What is the benefit of associating a private hosted zone with multiple VPCs in AWS Route 53?
Associating a private hosted zone with multiple VPCs allows you to use the same domain name across different VPCs, which can simplify DNS management and promote consistent DNS resolution across your AWS environment. This is particularly useful for large organizations with multiple VPCs who want to maintain consistent internal DNS records for services accessed across these VPCs.
How do you ensure that DNS records in a private hosted zone in Route 53 are only accessible within a specific VPC?
When you create a private hosted zone in Route 53, you have to associate it with one or more VPCs. DNS records in that private hosted zone are accessible only within these associated VPCs, ensuring that the DNS information is kept private and not accessible from the public internet. You can further control access by using VPC peering, AWS Direct Connect, or VPN connections.
Can you set up geolocation-based routing with AWS Route 53, and what is its use case?
Yes, Route 53 allows you to configure geolocation-based routing, which routes traffic to different endpoints based on the geographic location of the users. This is used to localize content, comply with legal requirements by serving localized content from certain regions, or to distribute load globally.
What steps are involved in migrating a DNS service from another provider to AWS Route 53 without downtime?
The steps involved in migrating a DNS service to AWS Route 53 without downtime typically include:
- Creating a Route 53 hosted zone that corresponds to the domain.
- Replicating the DNS records from the current DNS provider to the new hosted zone in Route
- Updating the DNS records in Route 53 to ensure they match the current records exactly.
- Reducing the TTL (time to live) values on the DNS records to minimize the caching period before the switch.
- Changing the domain’s NS records at the registrar to point to the Route 53 name servers.
- Monitoring traffic to ensure minimal to no downtime occurs during the transfer.
- Once confirmed that all traffic is routing correctly to Route 53, TTL values can be adjusted back to normal.
Note: The above answers are crafted to be correct as of the knowledge cutoff date. Therefore, always refer to the most recent AWS documentation for updates.
Thanks for this informative blog post! Setting up Route 53 hosted zones always seemed daunting, but this guide made it easier.
Really helpful! Can anyone explain the main difference between public hosted zones and private hosted zones in Route 53?
I appreciate the step-by-step instructions. The use of a private zonal DNS entry was a game-changer for optimizing application availability.
Great post! Does anyone know if there’s a way to automate the creation of Route 53 records using CloudFormation?
Setting up health checks along with Route 53 can significantly optimize your app’s availability. Anyone tried combining these two?
This blog post was very helpful to get me started with Route 53. Thank you!
I tried setting up a private hosted zone, but I’m having issues with resolving DNS names from inside my VPC. Any tips?
Good coverage on how to use Route 53 with multiple availability zones. This is essential for high availability architecture.