feat: enable dns tracing by default

also updates README to reflect the change, while adding links to hapi
and koa instrumentation that were missing

README.md

@@ -198,7 +198,9 @@ These plugins are hosted at <https://github.com/open-telemetry/opentelemetry-js-
 - [@opentelemetry/plugin-redis][otel-contrib-plugin-redis]
 - [@opentelemetry/plugin-ioredis][otel-contrib-plugin-ioredis]
 - [@opentelemetry/plugin-express][otel-contrib-plugin-express]
-- [@opentelemetry/plugin-dns][otel-contrib-plugin-dns] - By default, this plugin is not loaded [#612](https://github.com/open-telemetry/opentelemetry-js/issues/612)
+- [@opentelemetry/plugin-dns][otel-contrib-plugin-dns]
+- [@opentelemetry/hapi-instrumentation][otel-contrib-hapi-instrumentation]
+- [@opentelemetry/koa-instrumentation][otel-contrib-koa-instrumentation]
 
 #### Web Plugins
 
@@ -265,3 +267,5 @@ Apache 2.0 - See [LICENSE][license-url] for more information.
 [otel-contrib-plugin-express]: https://github.com/open-telemetry/opentelemetry-js-contrib/tree/master/plugins/node/opentelemetry-plugin-express
 [otel-contrib-plugin-user-interaction]: https://github.com/open-telemetry/opentelemetry-js-contrib/tree/master/plugins/web/opentelemetry-plugin-user-interaction
 [otel-contrib-plugin-document-load]: https://github.com/open-telemetry/opentelemetry-js-contrib/tree/master/plugins/web/opentelemetry-plugin-document-load
+[otel-contrib-hapi-instrumentation]: https://github.com/open-telemetry/opentelemetry-js-contrib/tree/master/plugins/node/opentelemetry-hapi-instrumentation
+[otel-contrib-koa-instrumentation]: https://github.com/open-telemetry/opentelemetry-js-contrib/tree/master/plugins/node/opentelemetry-koa-instrumentation

packages/opentelemetry-node/src/config.ts

@@ -40,4 +40,5 @@ export const DEFAULT_INSTRUMENTATION_PLUGINS: Plugins = {
   express: { enabled: true, path: '@opentelemetry/plugin-express' },
   '@hapi/hapi': { enabled: true, path: '@opentelemetry/hapi-instrumentation' },
   koa: { enabled: true, path: '@opentelemetry/koa-instrumentation' },
+  dns: { enabled: true, path: '@opentelemetry/dns' },
 };