TIL about socat, a Unix command that can be used to create bi-directional TCP proxies, much like ssh -L. Example (via), forward traffic from local port 8080 to example.com port 5545:
socat tcp-l:8080,fork,reuseaddr tcp:example.com:5545
Useful for setting up ad-hoc proxies to a Kubernetes cluster to access resources only available to the cluster itself. Launch socat using kubectx run with a port set in the cluster:
kubectl run --rm -it --port 8080 --image alpine \
--overrides='{"metadata":{"name":"my-proxy"}}' \
sh -- sh -c 'apk add socat && socat tcp-l:8080,fork,reuseaddr tcp:backend.example.com:5545'
Then, setup a port forward to your pod to access the port locally:
kubectl port-forward pod/my-proxy 8080:8080
With this, you can now access backend.example.com:5545 on localhost port 8080.
dev-notes