Update README.md (#1748)

* Update README.md

* Explicitly specify instrumentation packages

* Formatting

* Remove outdated sample containing broken link that no longer exists from README, fixes check-links

* Clarify wording

Author: wpessers

nodejs/README.md

@@ -5,8 +5,61 @@ the `AWS_LAMBDA_EXEC_WRAPPER` environment variable will initialize OpenTelemetry
 
 To use, add the layer to your function configuration and then set `AWS_LAMBDA_EXEC_WRAPPER` to `/opt/otel-handler`.
 
-[AWS SDK v2 instrumentation](https://github.com/aspecto-io/opentelemetry-ext-js/tree/master/packages/instrumentation-aws-sdk) is also
-included and loaded automatically if you use the AWS SDK v2.
+## Configuring auto instrumentation
+
+[AWS SDK v3 instrumentation](https://github.com/open-telemetry/opentelemetry-js-contrib/tree/main/plugins/node/opentelemetry-instrumentation-aws-sdk)
+is included and loaded automatically by default.
+A subset of instrumentations from the [OTEL auto-instrumentations-node metapackage](https://github.com/open-telemetry/opentelemetry-js-contrib/tree/main/metapackages/auto-instrumentations-node)
+are also included.
+
+Following instrumentations from the metapackage are included:
+- `amqplib`
+- `bunyan`
+- `cassandra-driver`
+- `connect`
+- `dataloader`
+- `dns` *- default*
+- `express` *- default*
+- `fs`
+- `graphql` *- default*
+- `grpc` *- default*
+- `hapi` *- default*
+- `http` *- default*
+- `ioredis` *- default*
+- `kafkajs`
+- `knex`
+- `koa` *- default*
+- `memcached`
+- `mongodb` *- default*
+- `mongoose`
+- `mysql` *- default*
+- `mysql2`
+- `nestjs-core`
+- `net` *- default*
+- `pg` *- default*
+- `pino`
+- `redis` *- default*
+- `restify`
+- `socket.io`
+- `undici`
+- `winston`
+
+Instrumentations annotated with "*- default*" are loaded by default.
+
+To only load specific instrumentations, specify the `OTEL_NODE_ENABLED_INSTRUMENTATIONS` environment variable in the lambda configuration.
+This disables all the defaults, and only enables the ones you specify. Selectively disabling instrumentations from the defaults is also possible with the `OTEL_NODE_DISABLED_INSTRUMENTATIONS` environment variable.
+
+The environment variables should be set to a comma-separated list of the instrumentation package names without the 
+`@opentelemetry/instrumentation-` prefix.
+
+For example, to enable only `@opentelemetry/instrumentation-http` and `@opentelemetry/instrumentation-undici`:
+```shell
+OTEL_NODE_ENABLED_INSTRUMENTATIONS="http,undici"
+```
+To disable only `@opentelemetry/instrumentation-net`:
+```shell
+OTEL_NODE_DISABLED_INSTRUMENTATIONS="net"
+```
 
 ## Building
 
@@ -31,5 +84,4 @@ You'll find the generated layer zip file at `./packages/layer/build/layer.zip`.
 Sample applications are provided to show usage of the above layer.
 
 - Application using AWS SDK - shows using the wrapper with an application using AWS SDK without code change.
-  - [Using layer built from source](./integration-tests/aws-sdk)
   - [WIP] [Using OTel Public Layer](./sample-apps/aws-sdk)