Route 53 and Networking Flashcards
You want to route all traffic from Europe to EU-WEST1, What routing policy would you use and what location would you specify for your users?
Geolocation and set location to “Europe’. R53 allows you to identify countries or continents
What is a multi-value answer routing policy and how do you set one up
An MVA policy will return a list of healthy endpoints to the client (Browser). You create multiple record sets containing an endpoint with associated health checks. When the record set is queried only healthy endpoints are returned and the browser picks one at random.
Is the domain registrar the same as a DNS?
No
What are the steps to use a 3rd party domain with R53
- You need to create a hosted zone in R53 using your domain.
- Update your 3rd party name server records to point to the AWS name servers provided when you create the hosted zone.
You have an R53 record-set pointing to an instances IP as the endpoint. You need to change this to an ELB. What record type do you currently have and what is it changed to?
You currently have an A (or AAAA for IPv6) and you will need to change to an Alias
There are 4 common record types in R53. What are they and what do they do?
A: URL to IPv4
AAAA: URL to IPv6
CNAME: URL to URL
ALIAS: URL to AWS Resource
How do health checks relate to DNS Queries
Only healthy resources will be returned as a response to a DNS query. This enables failover routing. Health checks are mandatory for fail over R53 Policy
can health checks be integrated with Cloudwatch?
Yes
Why would you use a weighted routing policy?
To control the percentage of requests going to a specific endpoint. Helpful for:
- A/B Deployments
- Splitting traffic between regions
What is the default health check interval in R53 and roughly how many health checkers will check and endpoint?
One every 30 second interval per health check with approximately 15 health checks per end point.
By default how many health checks need to fail for an instance to be unhealthy? How many for it to become healthy?
3 for both
When would you use a latency routing policy?
When latency for users is a priority. Under this policy traffic is redirected to the server that has the least latency as evaluated in terms of the user to the designated region.
In a latency routing policy will traffic be directed to the closest region?
Not especially. The lowest latency will be used which may not be the closest region to the user
Does R53 support healthchecks?
Yes - Health checks can be configured to simulate common user requests
What are the 6 routing policies for R53
Simple, Multivalue, Geo-location, latency, failover, weighted.
How are alias records resolved externally
As A or AAAA records
In R53 where can private domain names be resolved
Private Domain names can only be resolved by instances within your VPC
Does a simple routing policy allow for health checks?
No. You cannot attach a health check to a simple routing policy.
When would you use a simple routing policy?
When you only need to redirect to a single resource
If multiple values are returned from a simple routing policy, what action does the client take?
It picks a random value from the list
Can a CNAME record point to a root domain - i.e. planittesting.com
No. A CNAME record can only point to subdomains - i.e. test.planittesting.com
Why would you use a geolocation policy?
When you need to route traffic for specific users to specific regions based on their geographic location. You should always have a default policy if a region cannot be identified
What is the purpose of a default policy in R53 geolocation and is it mandatory?
The default policy is used if a match cannot be found based on the users location. It is not mandatory.
If you have a failover record-set in R53 called ‘failover’ which contains the IP for the primary and the secondary for the domain example.com - what is the URL for the primary and the secondary?
failover.example.com for both. R53 will switch from primary and secondary in the record-set automatically.
If you need a heath check to check just the connectivity of a port - which sort of health check would you use?
TCP health check
If you have an https health check does this verify the SSL certificate associated with the connection?
No
You have a weighted routing policy setup. 50% of traffic goes to EU-WEST-1, 50% goes to US-EAST-1. You change the policy to 70/30 respectively and go to the browser but the old policy seems to still be in effect - whats the simplest reason?
Its likely that the TTL has not expired and your browser is still executing from cache
Which layer does an application ELB work on?
Layer 7 - HTTP. Allows balancing on the URL. Allows balancing to multiple apps on the same instance.
What protocols can be used in an R53 health check?
HTTP, HTTPS, TCP
What are the 3 failover policies in R53?
Active/Active: R54 returns primary resource. In case of failure R53 returns backup resource. Must be a failover policy
Active/Passive: Multiple active resources. In case of failure return a healthy resource - any policy but failover
Combination of Both: Multiple routing policies built as a reee
What the maximum number of endpoints returned in an MVA query?
8
When would you use an MVA routing policy? Is this a replacement for an ELB?
When you want R53 to route traffic to multiple endpoints. It is not an ELB replacement
