Merge pull request #31 from Roblox/readme

Add limitations to README.md.

Author: shishir-a412ed

README.md

@@ -133,6 +133,19 @@ This will destroy your vagrant VM.
 ## Currently supported environments
 Ubuntu (>= 16.04)
 
+## Limitations
+
+`nomad-driver-containerd` [`v0.1`](https://github.com/Roblox/nomad-driver-containerd/releases/tag/v0.1) is **not** production ready.
+There are some open items which are currently being worked on.
+
+1) **Logging**: Logging is currently not supported i.e `nomad alloc logs` command won't work out-of-the-box for containers launched using `nomad-driver-containerd`. As a workaround, one can use `containerd` command line tool `ctr` to attach to container `stdout/stderr`. Both the issue and workaround is documented [`here`](https://github.com/Roblox/nomad-driver-containerd/issues/30)
+
+2) **Networking**: Networking is **not in scope** of containerd as described [`here`](https://kubernetes.io/blog/2017/11/containerd-container-runtime-options-kubernetes/). However an external CNI plugin can be used to add networking to the container. We are researching on how to enable networking for our internal use-cases, and would publish (open-source) that work at some point.
+
+3) **Port forwarding**: The ability to map a host port to a container port. This is currently not supported, but could be supported in future.
+
+4) **Consul connect**: When a user launches a job in `nomad`, s/he can add a [`service stanza`](https://www.nomadproject.io/docs/job-specification/service) which will instruct `nomad` to register the service with `consul` for service discovery. This is currently not supported.
+
 ## License
 
 Copyright 2020 Roblox Corporation