Kubernetes Transparent Proxy

Transparent proxy and filtering for Kubernetes pods.

This project provides transparent proxy to pods using two deployment scenarios:

1. On any K8S cluster with manual addition of the init container.
2. A K8S 1.7+ cluster with deployment annotations and initializers to inject the init container.

The init container is responsible for adding the firewall rules to redirect outbound http/s traffic to the proxy server.

See the Helm chart README.md for all chart configuration options.

Technology used:

• Kubernetes Initializers
• Kubernetes Controllers
• Kubernetes RBAC
• mitmproxy
• Kubernetes Helm
• Google Container Engine

Deploying without initializers

Kubernetes Initializers are in alpha as of 1.7. This section shows how to deploy and use the transparent proxy on a K8S 1.6 cluster.

Figure 1. tproxy diagram

1. Install the helm chart:

cd charts/tproxy
helm install -n tproxy .
cd -

2. Run the example app:

kubectl apply -f examples/debian-locked-manual.yaml

3. Inspect the logs:

kubectl logs --selector=app=debian-app,variant=locked --tail=4

Example output:

https://www.google.com: 418
https://storage.googleapis.com/solutions-public-assets/: 200
PING www.google.com (209.85.200.147): 56 data bytes
ping: sending packet: Operation not permitted

Deploying with Initializers

Using the Kubernetes Initializer simplifies the runtime configuration. The initializer automatically intercepts deployments with the annotation: "initializer.kubernetes.io/tproxy": "true"` and adds the init container to the deployment.

Figure 1. tproxy with initializers diagram

1. Create an alpha GKE cluster with initializer support:

gcloud container clusters create tproxy-example \
  --zone us-central1-f \
  --machine-type n1-standard-1 \
  --num-nodes 3 \
  --enable-kubernetes-alpha \
  --cluster-version 1.7.6

NOTE: Run gcloud container get-server-config --zone us-central1-f to see all cluster versions.

2. Install Helm:

curl -sL https://storage.googleapis.com/kubernetes-helm/helm-v2.5.1-linux-amd64.tar.gz | tar -zxvf - && sudo mv linux-amd64/helm /usr/local/bin/ && rm -Rf linux-amd64

helm init

3. Install the Helm Chart:

cd charts/tproxy
helm install -n tproxy --set tproxy.useInitializer=true .
cd -

4. Deploy the example app that uses the annotation:

kubectl create -f examples/debian-locked.yaml

5. Inspect the logs:

kubectl logs --selector=app=debian-app,variant=locked --tail=4

Example output:

https://www.google.com: 418
https://storage.googleapis.com/solutions-public-assets/: 200
PING www.google.com (209.85.200.147): 56 data bytes
ping: sending packet: Operation not permitted