docs: changed layout to be closer to the final one

Signed-off-by: Sam Alba <sam.alba@gmail.com>

docs/administrator/_category_.json

@@ -0,0 +1,4 @@
+{
+  "label": "Administrator Manual",
+  "position": 6
+}

docs/administrator/operator.md

@@ -0,0 +1,45 @@
+---
+sidebar_position: 2
+---
+
+# Dagger Operator Manual
+
+## Custom buildkit setup
+
+Dagger can be configured to use an existing buildkit daemon, running either locally or remotely. This can be done using two environment variables: `BUILDKIT_HOST` and `DOCKER_HOST`.
+
+To use a buildkit daemon listening on TCP port `1234` on localhost:
+
+```shell
+export BUILDKIT_HOST=tcp://localhost:1234
+```
+
+To use a buildkit daemon running in a container named "super-buildkit" on the local docker host:
+
+```shell
+export BUILDKIT_HOST=docker-container://super-buildkit
+```
+
+To use a buildkit daemon running on a remote docker host (be careful to properly secure remotely accessible docker hosts!)
+
+```shell
+export BUILDKIT_HOST=docker-container://super-buildkit
+export DOCKER_HOST=tcp://my-remote-docker-host:2376
+```
+
+## OpenTracing Support
+
+Both Dagger and buildkit support opentracing. To capture traces to
+[Jaeger](https://github.com/jaegertracing/jaeger), ), set the `JAEGER_TRACE` environment variable to the collection address.
+
+A `docker-compose` file is available to help bootstrap the tracing environment:
+
+```shell
+docker-compose -f ./tracing.compose.yaml up -d
+export JAEGER_TRACE=localhost:6831
+export BUILDKIT_HOST=docker-container://dagger-buildkitd-jaeger
+
+dagger compute ...
+```
+
+You can then go to [http://localhost:16686/](http://localhost:16686/) in your browser to see the traces.