docs(ai): add external containers docs (#687)

* docs(ai): add external container manager docs

This commit adds documentation for the external container manager
feature now that it has been thoroughly tested and some issues have been
fixed.

---------

Co-authored-by: 0xb79 <[email protected]>

Author: rickstaa

ai/orchestrators/models-config.mdx

@@ -40,7 +40,10 @@ currently **recommended** models and their respective prices.
   {
     "pipeline": "audio-to-text",
     "model_id": "openai/whisper-large-v3",
-    "price_per_unit": 12882811
+    "price_per_unit": 12882811,
+    "url": "<CONTAINER_URL>:<PORT>",
+    "token": "<OPTIONAL_BEARER_TOKEN>",
+    "capacity": 1
   },
   {
     "pipeline": "segment-anything-2",
@@ -65,7 +68,7 @@ currently **recommended** models and their respective prices.
     "model_id": "parler-tts/parler-tts-large-v1",
     "price_per_unit": 11,
     "pixels_per_unit": 1e2,
-    "currency": "USD",
+    "currency": "USD"
   }
 ]
 ```
@@ -93,6 +96,18 @@ currently **recommended** models and their respective prices.
 <ParamField path="optimization_flags" type="object">
   Optional flags to enhance performance (details below).
 </ParamField>
+<ParamField path="url" type="string" optional="true">
+  Optional URL and port where the model container or custom container manager software is running.  
+  [See External Containers](#external-containers)
+</ParamField>
+<ParamField path="token" type="string">
+  Optional token required to interact with the model container or custom container manager software.  
+  [See External Containers](#external-containers)
+</ParamField>
+<ParamField path="capacity" type="integer">
+  Optional capacity of the model. This is the number of inference tasks the model can handle at the same time. This defaults to 1.  
+  [See External Containers](#external-containers)
+</ParamField>
 
 ### Optimization Flags
 
@@ -134,3 +149,37 @@ are available:
   loss**. The speedup becomes more pronounced as the number of inference steps
   increases. Cannot be used simultaneously with `SFAST`.
 </ParamField>
+
+### External Containers
+
+<Warning>
+  This feature is intended for advanced users. Incorrect setup can lead to a
+  lower orchestrator score and reduced fees. If external containers are used, 
+  it is the Orchestrator's responsibility to ensure the correct container with 
+  the correct endpoints is running behind the specified `url`. 
+</Warning>
+
+External containers can be for one model to stack on top of managed model containers, 
+an auto-scaling GPU cluster behind a load balancer or anything in between. Orchestrators
+can use external containers to extend the models served or fully replace the AI Worker managed model containers
+using the [Docker client Go library](https://pkg.go.dev/github.com/docker/docker/client)
+to start and stop containers specified at startup of the AI Worker. 
+  
+External containers can be used by specifying the `url`, `capacity` and `token` fields in the
+model configuration. The only requirement is that the `url` specified responds as expected to the AI Worker same
+as the managed containers would respond (including http error codes). As long as the container management software
+acts as a pass through to the model container you can use any container management software to implement the custom 
+management of the runner containers including [Kubernetes](https://kubernetes.io/), [Podman](https://podman.io/), 
+[Docker Swarm](https://docs.docker.com/engine/swarm/), [Nomad](https://www.nomadproject.io/), or custom scripts to 
+manage container lifecycles based on request volume
+
+
+- The `url` set will be used to confirm a model container is running at startup of the AI Worker using the `/health` endpoint. 
+  Inference requests will be forwarded to the `url` same as they are to the managed containers after startup.
+- The `capacity` should be set to the maximum amount of requests that can be processed concurrently for the pipeline/model id (default is 1).
+  If auto scaling containers, take care that the startup time is fast if setting `warm: true` because slow response time will 
+  negatively impact your selection by Gateways for future requests.
+- The `token` field is used to secure the model container `url` from unauthorized access and is strongly
+  suggested to use if the containers are exposed to external networks.
+
+We welcome feedback to improve this feature, so please reach out to us if you have suggestions to enable better experience running external containers.