58. Route 53 Routing Policies

Following routing policies are available with Route 53:
i) Simple Routing
ii) Weighted Routing
iii) Latency Based Routing
iv) Failover Routing
v) Geolocation Routing
vi) Geoproximity Routing (Traffic Flow Only)
vii) Multivalue Answer Routing

Question 1:
The development team at an e-commerce startup has set up multiple microservices running on EC2 instances under an Application Load Balancer. The team wants to route traffic to multiple back-end services based on the URL path of the HTTP header. So it wants requests for www.example.com/orders to go to a specific microservice and requests for www.example.com/products to go to another microservice.
Which of the following features of Application Load Balancers can be used for this use-case?
Options:
A. Path-based Routing
B. HTTP header-based routing
C. Query string parameter-based routing
D. Host-based routing
Answer: A
Explanation
Correct option:
Path-based Routing
Elastic Load Balancing automatically distributes incoming application traffic across multiple targets, such as Amazon EC2 instances, containers, IP addresses, and Lambda functions.
If your application is composed of several individual services, an Application Load Balancer can route a request to a service based on the content of the request. Here are the different types –
Host-based Routing:
You can route a client request based on the Host field of the HTTP header allowing you to route to multiple domains from the same load balancer.
Path-based Routing:
You can route a client request based on the URL path of the HTTP header.
HTTP header-based routing:
You can route a client request based on the value of any standard or custom HTTP header.
HTTP method-based routing:
You can route a client request based on any standard or custom HTTP method.
Query string parameter-based routing:
You can route a client request based on the query string or query parameters.
Source IP address CIDR-based routing:
You can route a client request based on source IP address CIDR from where the request originates.
Path-based Routing Overview:
You can use path conditions to define rules that route requests based on the URL in the request (also known as path-based routing).
The path pattern is applied only to the path of the URL, not to its query parameters.
Incorrect options:
Query string parameter-based routing
HTTP header-based routing
Host-based Routing
As mentioned earlier in the explanation, none of these three types of routing support requests based on the URL path of the HTTP header. Hence these three are incorrect.