Overview
Define how Route 53 responds to DNS queries
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Don't get confused by the word "Routing"
- It's not the same as Load Balancer routing which routes the traffic
- DNS does not route any traffic, it only responds to the DNS queries
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Route 53 supports the following Routing Policies
- Simple
- Weighted
- Failover
- Latency based
- Geolocation
- IP-based
- Multi-Value Answer
- Geoproximity (using Route 53 Traffic Flow feature)
Routing Policies - Simple
Typically, route traffic to a single resource
Can specify multiple values in the same record
If multiple value are returned, a random one is chosen by the client
When Alias enabled, specfy only one AWS resource
Can't be associated with Health Checks
Routing Policies - Weighted
Control the % of the requests that go to each specific resource
Assign each record a relative weight:
traffic(%) = weight of the records / sum of all the weightWeights don't need to sum up to 100
DNS records must have the same name and type
Can be associated with Health Checks
Use cases: load balancing between regions, testing new application versions, ...
Assign a weight of 0 to a record to stop sending traffic to a resource
If all records have weight of 0, then all records will be returned equally
Routing Policies - Latency-based
Redirect to the resource that has the least latency close to us
Super helpful when latency for users is a priority
Latency is based on traffic between users and AWS Regions
Germany users may be directed to the US (if that is the lowest latency)
Can be associated with Health Checks (has a failover capability)
Routing Policies - Failover (Active - Passive)
You designate a primary resource and a secondary (or failover) resource. The primary resource is the one that Route 53 will route traffic to under normal conditions
Route 53 performs health checks on the primary resource to determince its availability
If the primary resource becomes unhealthy, Route 53 will redirect traffic to the secondary resource without manual intervention
Use cases: high vailability dns, desaster recovery
Routing Policies - Geolocation
Different from Latency-based
This routing is based on user location
Specify location by Continent, Contry or by US State (if there is overlapping, most precise location selected)
Should create a "Default" record (in case there is no match on location)
Use cases: website localization, restrict content distribution, load balancing, ...
Can be associated with Health Checks
Routing Policies - Geoproximity
Route traffic to your resources based on the geographic location of users and resources
Ability to shift more traffic to resources based on the defined bias
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To change the size of the geographic region, specify bias values:
- To expand (1 to 99) - more traffic to the resource
- To shrink (-1 to -99) - less traffic to the resource
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Resources can be:
- AWS resources (specify AWS Region)
- Non-AWS resources (specify Latitude and Longitude)
You must use Route 53 Traffic Flow (advanced) to use this feature
Routing Policies - IP-basd Routing
Routing is based on client's IP addresses
You provide a list of CIDRs for your clients and the corresponding endpoints/locations (user-IP-to-endpoint mappings)
Use cases: Optimize performance, reduce network costs, ...
Example: route end users from a particular ISP to a specific endpoint
Routing Policies - Multi-Value
Use when routing traffic to multiple resources
Route 53 return multiple values/resources
Can be associated with Health Checks (return only values for healthy resources)
Up to 8 healthy records are returned for each Multi-Value query
Multi-Value is not a substitue for having an ELB
Domain Registrar vs DNS Service
You buy or register your domain name with a Domain Registrar typically by paying annual charges (e.g., GoDaddy, Amazon Registra Inc, Hostinger, ...)
The Domain Registrar usually provides you with a DNS service to manage your DNS records
But you can use another DNS service to manage your DNS records
Example: purchase the domain from GoDaddy and use Route 53 to manage your DNS records
So if you buy your domain on a 3rd party registrar, you can still use Route 53 as the DNS Service provider
Create a Hosted Zone in Route 53
Update NS Records on 3rd party website to use Route 53 Name Servers
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