Serverless Framework — AWS Lambda MicroVMs (sandboxes) — complete example

A complete, deploy-as-is showcase of the sandboxes top-level property, which deploys AWS Lambda MicroVMs. serverless deploy works with no edits — read serverless.yml top to bottom and you've seen most of what the feature does.

The single api sandbox exercises: a local Dockerfile build, minimumMemory, description, environment, lifecycle hooks (ready + run), full observability (custom metric filters, alarms → a self-contained SNS topic, and a dashboard), custom iam, and tags. VPC egress and a pre-built s3:// artifact are included as commented blocks (they need account-specific IDs).

The app (app/app.js) is a tiny Node.js echo server on :8080 plus a lifecycle-hook server on :9000.

What gets created

serverless deploy provisions, for the api sandbox:

• AWS::Lambda::MicrovmImage — the sandbox image (built in-cloud from ./app)
• build + execution IAM roles (least-privilege, plus your custom iam statements)
• a CloudWatch log group (/aws/lambda-microvms/sandboxes-example-api-<stage>)
• a metric filter + alarm for each observability.metrics.filters entry (errors, warnings)
• an SNS topic (AlertTopic) the alarms publish to
• one dashboard per service — sandboxes-example-<stage>-sandboxes

Deploy

serverless deploy

✔ Service deployed to stack sandboxes-example-dev (…s)

dashboard: https://<region>.console.aws.amazon.com/cloudwatch/home?region=<region>#dashboards/dashboard/sandboxes-example-dev-sandboxes

serverless deploy prints the CloudWatch dashboard URL for the service — open it to see the metrics, logs, and alarm widgets.

After deploy, subscribe to the alerts topic to actually receive alarm notifications:

aws sns subscribe --protocol email --notification-endpoint you@example.com \
  --topic-arn "$(aws sns list-topics --query "Topics[?contains(TopicArn,'AlertTopic')].TopicArn | [0]" --output text)"

Invoke

serverless invoke --sandbox api --path /hello
# --sandbox is required (it names which sandbox to call) and is the invoke target.
# --method and --path are optional (default GET /).

The app echoes the request; GREETING is the environment variable from serverless.yml:

{"method":"GET","path":"/hello","headers":{"host":"<microvm-id>.lambda-microvm.us-east-1.on.aws"},"body":"","GREETING":"hello-from-sandboxes"}

See the alarm and dashboard react

observability is on by default. To watch it work, send a few requests whose log lines match the errors filter, then open the dashboard URL from the deploy output:

for i in 1 2 3 4 5 6; do serverless invoke --sandbox api --path "/error-$i" >/dev/null; done

Within ~2 minutes the dashboard's errors metric climbs to 6 and the errors alarm flips to ALARM (threshold 5); a few /warn-* requests move the warnings metric without tripping its alarm (3 ≤ 5).

Logs

Defaults to the last 10 minutes of events; widen the window with --startTime:

serverless logs --sandbox api --startTime 30m

Develop locally

Run the sandbox on your machine (Docker), with the same config — edits to app/ rebuild the image automatically:

serverless dev --sandbox api

It starts a local, SDK-compatible AWS Lambda MicroVMs emulator (prints its endpoint, e.g. http://127.0.0.1:9100); point the AWS SDK/CLI at that endpoint (--endpoint-url) to launch the sandbox locally with no cloud cost.

Roll back

Each deploy is retained; roll back to a previous one:

serverless deploy list            # list timestamps
serverless rollback --timestamp <timestamp>

Remove

serverless remove

Enabling the commented examples

• VPC egress (worker): uncomment the block and set vpc.subnetIds / vpc.securityGroupIds to IDs from your account. Subnets must be in MicroVM-supported Availability Zones (in us-east-1, avoid use1-az3).
• Pre-packaged S3 artifact (prebuilt): zip and upload the app source, then set the s3:// URI (the framework still builds the image in-cloud from it):
  cd app && zip -r /tmp/worker-src.zip . && aws s3 cp /tmp/worker-src.zip s3://<your-bucket>/worker-src.zip
  

See ../minimal/ for the smallest possible configuration (just artifact).