AWS Loadbalancer and Autoscaling Flashcards
What types of load balancers can you have in AWS?
- Classic LB
- Network NLB
- Application ALB
Is an ELB, highly available?
Yes, it is created in a region and across multiple AZ’s in the region.
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How does AWS create a logical ELB in AWS?
The logical LB is created from several nodes distributed into the available AZ’s. As you see each of these nodes has a separate public IP, to enable it to seems as if you are connecting to a single endpoint of the ELB, AWS creates a URL they you connect to when accessing the ELB, this URL will return all the ELBs of the ELBs to you. This causes an issue in that the load may not be distributed equally depending on how my instances you have in each AZ, to get around this the ELB has cross zones replication, in classic LB you had to enable it, newer LBs have it enabled by default.
When using an ELB with an autoscaling group, what has the autoscaling group to do as it adds and removes nodes?
The autoscaling group has to add and remove the registration of the nodes with the ELB target group.
Can you use an ELB without Autoscaling group?
Yes, you just have to register the instances with the ELB target group.
What is an ELB target group used for?
A target group is used to group instances the ELB will distribute traffic to.
Should, I use classic LB?
No, they are moving away from this LB, you should use NLB or ALB.
What transports do classic LB support?
TCP, SSL, HTTP, HTTS
In a classic LB do I get a security group for my ELB?
Yes, when you create an ELB you create or assign a security group.
What are ELB health checks?
ELB performs a check on the backend instance, by performing one of the following,
- Checking the instance status
- Sending an HTTP/HTTPs request and checking th response code.
If the software running on my webserver holds state and requires thet any returning request be sent to the same server node, is this possible with ELB
Use ELB client sticky session, you have two options,
- LB generate cookies
- Application generated cookies
I the classic ELB a layer 7 device?
No
What is an ALB?
It is an application load balancer and operates at layer 7 with a wider set of services,
- EC2
- Contaners
- Lambda
I require the ability to route HTTP traffic based on the path, what LB should I use?
ALB
I require an LB that can route based on path and can be internal facing, what type of ELB should I choose?
ALB
I require an LB that will work for both IPv4 and IPv6, what ELB should I use?
ALB
What is the target group?
It is a collection of instances.
I am using a lambda function and I wnat to have an LB in front of it so I can control the traffic going to different function and also to enable blue/green deployments, what is my best option?
Use an AL, ALB support Lambda functions.
Does NLB support WebSockets?
No, you will need an ALB
I have a multiple application that needs an LB, what LB can I used the also can do rooting at L7?
You cna use the ALB, it enables you to route based on pat and domain.
Can I use multiple certs on an ALB?
Yes.
I want to understand who is hitting my LB, how and I architect this?
LB’s support access logs and enable you to capture th logs.
I want to understand who is hitting my LB, how and I architect this?
LB’s support access logs and enable you to capture the logs.