kubectl port-forwarding fails during use with moby: socat missing on VM

[ericpromislow]

Rancher Desktop Version

dev->1.0.0-beta1

Rancher Desktop K8s Version

1.21.6

What operating system are you using?

macOS

Operating System / Build Version

macOS Monterey 12.0.1

What CPU architecture are you using?

x64

Windows User Only

No response

Actual Behavior

Terminal 1:

$ kubectl port-forward $ALPACA_POD 48858:8080
Forwarding from 127.0.0.1:48858 -> 8080
Forwarding from [::1]:48858 -> 8080

Terminal 2:

curl http://localhost:48858/

Back to Terminal 1:

Handling connection for 48858
E0114 14:08:58.698803   17224 portforward.go:406] an error occurred forwarding 48858 -> 8080: error forwarding port 8080 to pod c5993e2de9902e4bb3fe8c579d8c41613fa34af5b67b6ecdbeaab5f4521c8574, uid : unable to do port forwarding: socat not found
E0114 14:08:58.699114   17224 portforward.go:234] lost connection to pod

Fix is to run sudo apk add socat on the VM

Steps to Reproduce

Ensure you're using the moby container engine. No problem with containerd

Do the following in terminal 1:

Install the sample app:

kubectl run alpaca-prod   --image=gcr.io/kuar-demo/kuard-amd64:blue --port=8080 --labels="ver=1,app=alpaca,env=prod"

Background on kubectl:

$ which kubectl
/usr/local/bin/kubectl

$ ls -l /usr/local/bin/kubectl
lrwxr-xr-x  1 OWNER GROUP 67 12 Jan 15:09 /usr/local/bin/kubectl -> .../workspace/rancher/desktop/resources/darwin/bin/kubectl

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"23", GitVersion:"v1.23.1", GitCommit:"86ec240af8cbd1b60bcc4c03c20da9b98005b92e", GitTreeState:"clean", BuildDate:"2021-12-16T11:41:01Z", GoVersion:"go1.17.5", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"23", GitVersion:"v1.23.1+k3s2", GitCommit:"a0cadcd3436745396c82821b4a0803ee460401e1", GitTreeState:"clean", BuildDate:"2022-01-14T08:22:21Z", GoVersion:"go1.17.5", Compiler:"gc", Platform:"linux/amd64"}

Now expose the app and port-forward to it:

$ kubectl expose pod alpaca-prod
$ kubectl port-forward alpaca-prod 48858:8080

Now switch to terminal 2 and hit the app through the port-forwarded tunnel:

curl http://localhost:48858/

Back to Terminal 1:

Handling connection for 48858
E0114 14:08:58.698803   17224 portforward.go:406] an error occurred forwarding 48858 -> 8080: error forwarding port 8080 to pod c5993e2de9902e4bb3fe8c579d8c41613fa34af5b67b6ecdbeaab5f4521c8574, uid : unable to do port forwarding: socat not found
E0114 14:08:58.699114   17224 portforward.go:234] lost connection to pod

Result

See above

Expected Behavior

Curl should dump a bunch of html output

Additional Information

No response

[ericpromislow]

Notes on Windows:

1. Running both kubectl port-forward and curl in Windows Powershell terminals: works
2. Running kubectl port-forward in Windows Powershell, curl in Ubuntu/WSL: curl fails to connect to localhost:48858 fails as expected
3. Running both in Ubuntu/WSL: works

Verified that we're running moby, not containerd.

[3r1co]

For some strange reason, sudo and apk are missing in my Rancher Desktop VM, but I managed to get around this with the following command:

docker run --rm -it -v /usr/bin:/usr/bin -v /usr/lib:/usr/lib alpine apk add socat

I'm also using Windows 10 with WSL2.

Maybe that helps someone having the same issue, but having socat as part of the base image would be really appreciated :-)

[jandubois]

having socat as part of the base image would be really appreciated

Will be fixed when #1280 is merged; should be in the 1.0.0 final release.