EBS and Load Balancers

Day-4_AWS_Assignment

1. What are EBS Volumes?

EBS stands for Elastic Block Stores. They are persistent volumes that you can attach to the instances. With EBS volumes, your data will be preserved even when you stop your instances, unlike your instance store volumes where the data is deleted when you stop the instances.

2. What are the types of volumes for EC2 instances?

Following are the types of volumes in EBS

• General purpose

• Provisioned IOPS

• Magnetic

• Cold HDD

• Throughput optimized

3. What is the difference between Instance Store and EBS Volume?

EBS is attached to the EC2 instance for long-term data storage.	An instance store is used to store short-term data temporarily.
While using EBS as the storage type, the instances can be stopped and restarted without any data loss.	There is no option through which the user can stop and then restart the instance, the option that AWS provides while using the instance store is only to terminate the instance.
EBS volumes can be restored through the snapshots of the instances.	Instance Store is associated with the S3 templates.
EBS volumes can be attached, detached, and reattached to the EC2 instance.	The instance store volume cannot be detached or reattached.

4. Is it possible to modify/reduce/increase the size of EBS volume?

It is impossible to decrease EBS volume size. When you have 100GB EBS and you decide to modify it into 30GB you will get the error: The size of a volume can only be increased, not decreased.

5. What is an ELB?

ELB stands for Elastic Load balancing. ELB automatically distributes the incoming application traffic or network traffic across multiple targets like EC2, containers, and IP addresses.

6. What is the difference between NLB, CLB and ALB?

Application Load Balancer (ALB): ALB allows routing based on port numbers. It can also route requests to Lambda, and it can direct requests to many ports on the target. Application Load Balancer supports only layer 7 - HTTP/2 and Web Sockets. It can return primary responses on its own so the server can be set free of replying to redundant requests. ALB find use in Microservices and application.

Network Load Balancer (NLB): Network Load Balancer supports Layer 4 which is TCP and UDP. It is faster and high-performance since it is lower in the OSI model. It uses static IPs and can also be assigned elastic IPs. An example would be real-time data streaming or video streaming.

Classic Load Balancer (CLB) or Elastic Load Balancer (ELB version 1): ELB is the oldest Load balancer and the only one that offers application-specific sticky session cookies. It works both on Layer 7 and Layer 4. ELB also supports EC2-Classic.

7. What are Target Groups and where are they used?

Each target group is used to route requests to one or more registered targets. When you create a listener, you specify a target group for its default action. Traffic is forwarded to the target group specified in the listener rule. You can create different target groups for different types of requests.

If a target group is configured with the TLS protocol, the load balancer establishes TLS connections with the targets using certificates that you install on the targets.

When you create a target group, you specify its target type, which determines how you specify its targets. After you create a target group, you can't change its target type.

8. What are Health Checks in Load Balancers?

You register your targets with one or more target groups. The load balancer starts routing requests to a newly registered target as soon as the registration process is completed and the target passes the initial health checks. It can take a few minutes for the registration process to complete and health checks to start.

Network Load Balancers use active and passive health checks to determine whether a target is available to handle requests. By default, each load balancer node routes requests only to the healthy targets in its Availability Zone.

9. What is the internal DNS name in the load balancer?

The DNS name of an internal load balancer is publicly resolvable to the private IP addresses of the nodes. Therefore, internal load balancers can only route requests from clients with access to the VPC for the load balancer.

10. What is an internal and public-facing load balancer?

Public Load Balancers are used to load balance internet traffic to your VMs. An internal (or private) load balancer is used where private IPs are needed at the front end only. Internal load balancers are used to load balance traffic inside a virtual network.