====== AWS CLI - Create a Network Load Balancer  ======

[[https://docs.aws.amazon.com/elasticloadbalancing/latest/network/network-load-balancer-cli.html|AWS ELB]]

===== Before you begin =====

Install the AWS CLI or update to the current version of the AWS CLI if
you are using a version that does not support Network Load Balancers.
For more information, see Installing the AWS Command Line Interface in
the AWS Command Line Interface User Guide.

Decide which Availability Zones you will use for your EC2 instances.
Configure your virtual private cloud (VPC) with at least one public
subnet in each of these Availability Zones.

Launch at least one EC2 instance in each Availability Zone. Ensure that
the security groups for these instances allow TCP access from clients on
the listener port and health check requests from your VPC. For more
information, see Target security groups.

===== Create your load balancer =====

Use the create-load-balancer command to create a load balancer,
specifying a public subnet for each Availability Zone in which you
launched instances. You can specify only one subnet per Availability
Zone.

    aws elbv2 create-load-balancer --name my-load-balancer --type network 
    --subnets subnet-0e3f5cac72EXAMPLE

The output includes the Amazon Resource Name (ARN) of the load balancer,
with the following format:

    arn:aws:elasticloadbalancing:us-east-2:123456789012:loadbalancer/net/my-load-balancer/1234567890123456

Use the create-target-group command to create a target group, specifying
the same VPC that you used for your EC2 instances:

    aws elbv2 create-target-group --name my-targets --protocol TCP \
    --port 80 --vpc-id vpc-0598c7d356EXAMPLE

The output includes the ARN of the target group, with this format:

    arn:aws:elasticloadbalancing:us-east-2:123456789012:targetgroup/my-targets/1234567890123456

Use the register-targets command to register your instances with your
target group:

    aws elbv2 register-targets --target-group-arn targetgroup-arn \
    --targets Id=i-1234567890abcdef0 Id=i-0abcdef1234567890

Use the create-listener command to create a listener for your load
balancer with a default rule that forwards requests to your target
group:

    aws elbv2 create-listener --load-balancer-arn loadbalancer-arn --protocol TCP --port 80  \
    --default-actions Type=forward,TargetGroupArn=targetgroup-arn

The output contains the ARN of the listener, with the following format:

    arn:aws:elasticloadbalancing:us-east-2:123456789012:listener/net/my-load-balancer/1234567890123456/1234567890123456

(Optional) You can verify the health of the registered targets for your
target group using this describe-target-health command:

    aws elbv2 describe-target-health --target-group-arn targetgroup-arn

===== Specify an Elastic IP address for your load balancer =====

When you create a Network Load Balancer, you can specify one Elastic IP
address per subnet using a subnet mapping.

    aws elbv2 create-load-balancer --name my-load-balancer --type network \
    --subnet-mappings SubnetId=subnet-0e3f5cac72EXAMPLE,AllocationId=eipalloc-12345678

===== Delete your load balancer =====

When you no longer need your load balancer and target group, you can
delete them as follows:

    aws elbv2 delete-load-balancer --load-balancer-arn loadbalancer-arn
    aws elbv2 delete-target-group --target-group-arn targetgroup-arn