Elastic Load Balancing v2: Create listener from the CLI

Part 233 of AWS from Zero. This is lesson 8 in the Elastic Load Balancing v2 track.

What we are learning

Use create-listener to create or register one Elastic Load Balancing v2 resource through the CLI. This lesson identifies the required input shape, saves the raw response, and keeps inspection separate from execution.

The AWS CLI operation is aws elbv2 create-listener. Required operation inputs: --load-balancer-arn (string), --default-actions (list). The modeled top-level response contains Listeners.

Before you run it

aws sts get-caller-identity
REGION="${AWS_REGION:-ap-south-1}"
LOAD_BALANCER_ARN="replace-with-load-balancer-arn"
aws elbv2 create-listener help

Use a sandbox account or an approved learning environment. Read the operation help before supplying identifiers, ARNs, network ranges, policy documents, or customer data.

Cost note: Load balancers, LCUs, capacity units, and processed data can incur charges.

The command

aws elbv2 create-listener \
  --generate-cli-skeleton input > part-233-request.json
 
# Edit every placeholder in part-233-request.json, then run:
aws elbv2 create-listener \
  --cli-input-json file://part-233-request.json \
  --region "$REGION" \
  --output json > part-233-response.json

The response is saved to part-233-response.json so inspection is separate from execution. Review part-233-request.json, replace every placeholder, and remove unsupported optional fields before the real call.

Inspect the result

node -e "const r=require('./part-233-response.json'); console.log(Object.keys(r))"
node -e "const r=require('./part-233-response.json'); console.log(JSON.stringify(r, null, 2))"

Compare the returned identifiers and status fields with the account, Region, and resource you intended to target. For asynchronous operations, continue with the service's matching get, list, or describe command until it reaches a terminal state.

One tiny variation

node -e "const r=require('./part-233-response.json'); console.log(JSON.stringify(r["Listeners"], null, 2))"

This variation changes output inspection rather than adding another infrastructure concept. Keep the raw JSON while developing a query so a narrow projection does not hide an error or unexpected field.

Common mistake

Do not run a generated request unchanged. Replace every placeholder, add ownership tags where supported, estimate cost, and verify that the selected Region and account are disposable.

Cleanup

# Review the inverse operation before removing the demo resource.
aws elbv2 delete-listener help
rm -f part-233-request.json part-233-response.json part-233-payload.bin part-233-debug.log

Local request and response files may contain account IDs, ARNs, names, or service configuration. Remove them when the lab is complete and follow dependency-aware cleanup for any AWS resource you created.

Next, we will learn Elastic Load Balancing v2: Create load balancer from the CLI.

Official AWS CLI reference