Route 53 Flashcards
This deck aims to help retain concepts related to the AWS Route 53 service.
What are the main features of a Route 53 Public Hosted Zone?
- Accessible from both the public internet and VPCs
- Authoritative for a specific domain
- Externally registered domains can point to a Route 53 Public Hosted Zone
- Hosts DNS records (e.g. A, AAAA, MX, NS, TXT)
Which Route 53 component contains information about how to route traffic on the internet for a specific domain and its subdomains?
Public Hosted Zone
What Route 53 feature allows DNS resolution for internal resources accessible only within specified VPCs?
Private Hosted Zone
What are the main features of a Route 53 Private Hosted Zone?
- Inaccessible from the public internet
- Accessible only from associated VPCs (from current account or other accounts)
What instructions reside in authoritative DNS servers and provide information about a domain, including the associated IP address and how to handle requests for that domain?
DNS Records
When creating a DNS record in Route 53, what configurations must be provided?
- Record Name (e.g., accounting.example.com),
- Record Type (e.g., A)
- Record Value (e.g. 229.44.81.208)
- TTL in seconds (e.g., 300)
- Routing Policy (e.g., simple routing)
Which architectural approach allows the DNS server to respond differently to the same DNS query based on the source of the query (public or private)?
Split-view DNS
Hosted Zones (Public and Private) can mirror their records, but additional subdomains may only be accessible from VPCs associated with a Private Hosted Zone and not from the Public
What is the difference between CNAME and ALIAS record types?
- CNAME maps a name to another name (e.g. www.example.com to example.com) and cannot be used for the apex domain (e.g. example.com)
- ALIAS is an AWS-specific record type used only in Route 53 that maps a name to an AWS resource (e.g. example.com to an Elastic Load Balancer, API Gateway, CloudFront, Elastic Beanstalk, Global Accelerator, S3), it can be used for the apex domain, incurs no additional cost, and is the default choice for routing traffic to AWS services
What types of Route 53 Health Checks are available?
- Endpoint health check
- Calculated health check (monitors status of other health checks)
- State of CloudWatch alarms health check
Are Route 53 Health Checks configured within Route 53 records?
Health Checks are configured separately but are used by Route 53 records
Which Route 53 feature monitors the health and performance of web applications, web servers, and other resources?
Route 53 Health Checks
How are Route 53 Health Checks performed, and how frequently?
Health checks are performed every 30 seconds (default), or every 10 seconds (with additional cost), by globally distributed health checkers
Which protocols are supported for Route 53 Health Checks?
- TCP
- HTTP/HTTPS
- HTTP/HTTPS with String Matching
What criteria does Route 53 use to determine if an endpoint is healthy?
An endpoint is considered healthy if 18% or more of health checkers report that the endpoint is healthy
Does Route 53 return records that fail Health Checks?
No, unhealthy record is not returned in DNS queries, an SNS topic can be configured to trigger notifications when an endpoint is unhealthy