Remote Debugging Python Applications Runnning on Kubernetes

Setup for remote and interactive debugging of Python application running in Kubernetes.

Works with VS Code debugger. Can be used to debug multiple containers/pods at the same time

Repository includes two sample applications (app1 and app2 directories) and debug configuration for VS Code.

Accompanying article:

• Remote Interactive Debugging of Python Applications Running in Kubernetes

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Setup

Create cluster:

minikube start --kubernetes-version=v1.26.3

Build and deploy applications:

docker build -f app1/Dockerfile -t docker.io/martinheinz/python-debugging-app1:v1.0 app1
docker build -f app2/Dockerfile -t docker.io/martinheinz/python-debugging-app2:v1.0 app2

minikube image load docker.io/martinheinz/python-debugging-app1:v1.0
minikube image load docker.io/martinheinz/python-debugging-app2:v1.0

# ... or docker push ...

kubectl apply -f deployment.yaml

Build debugger image:

docker build -f debugger.Dockerfile -t docker.io/martinheinz/python-debugger:v1.0 .
minikube image load docker.io/martinheinz/python-debugger:v1.0

To debug:

1. Inject the ephemeral container into application Pods:

# Deployment patch
APP1_POD=$(kubectl get -l=app=app1 pod --output=jsonpath='{.items[0].metadata.name}')
APP2_POD=$(kubectl get -l=app=app2 pod --output=jsonpath='{.items[0].metadata.name}')
./create-debug-container.sh default "$APP1_POD" app1
./create-debug-container.sh default "$APP2_POD" app2

2. Forward application and debugger traffic to local:

kubectl port-forward "$APP1_POD" 5000 5678 &
kubectl port-forward "$APP2_POD" 5679:5678 &

3. Add breakpoints to your code
4. Launch debugger(s)

5. Query application API (curl localhost:5000)