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Kubectl plugin to ease sniffing on kubernetes pods using tcpdump and wireshark
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README.md

ksniff

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A kubectl plugin that utilize tcpdump and Wireshark to start a remote capture on any pod in your Kubernetes cluster.

You get the full power of Wireshark with minimal impact on your running pods.

Intro

When working with micro-services, many times it's very helpful to get a capture of the network activity between your micro-service and it's dependencies.

ksniff use kubectl to upload a statically compiled tcpdump binary to your pod and redirecting it's output to your local Wireshark for smooth network debugging experience.

Demo

Demo!

Production Readiness

Ksniff isn't production ready yet, running ksniff for production workloads isn't recommended at this point.

Installation

Installation via krew (https://github.com/GoogleContainerTools/krew)

kubectl krew install sniff

For manual installation, download the latest release package, unzip it and use the attached makefile:

unzip ksniff.zip
make install

Build

Requirements:

  1. libpcap-dev: for tcpdump compilation (Ubuntu: sudo apt-get install libpcap-dev)
  2. jq: for parsing kubectl version
  3. go 1.11 or newer

Compiling:

linux:      make linux
windows:    make windows
mac:        make darwin

To compile a static tcpdump binary:

make static-tcpdump

Usage

kubectl < 1.12:
kubectl plugin sniff <POD_NAME> [-n <NAMESPACE_NAME>] [-c <CONTAINER_NAME>] [-i <INTERFACE_NAME>] [-f <CAPTURE_FILTER>] [-o OUTPUT_FILE] [-l LOCAL_TCPDUMP_FILE] [-r REMOTE_TCPDUMP_FILE]

kubectl >= 1.12:
kubectl sniff <POD_NAME> [-n <NAMESPACE_NAME>] [-c <CONTAINER_NAME>] [-i <INTERFACE_NAME>] [-f <CAPTURE_FILTER>] [-o OUTPUT_FILE] [-l LOCAL_TCPDUMP_FILE] [-r REMOTE_TCPDUMP_FILE]

POD_NAME: Required. the name of the kubernetes pod to start capture it's traffic.
NAMESPACE_NAME: Optional. Namespace name. used to specify the target namespace to operate on.
CONTAINER_NAME: Optional. If omitted, the first container in the pod will be chosen.
INTERFACE_NAME: Optional. Pod Interface to capture from. If omited, all Pod interfaces will be captured.
CAPTURE_FILTER: Optional. specify a specific tcpdump capture filter. If omitted no filter will be used.
OUTPUT_FILE: Optional. if specified, ksniff will redirect tcpdump output to local file instead of wireshark.
LOCAL_TCPDUMP_FILE: Optional. if specified, ksniff will use this path as the local path of the static tcpdump binary.
REMOTE_TCPDUMP_FILE: Optional. if specified, ksniff will use the specified path as the remote path to upload static tcpdump to.

Non-Privileged and Scratch Pods

To reduce attack surface and have small and lean containers, many production-ready containers runs as non-privileged user or even as a scratch container.

To support those containers as well, ksniff now ships with the "-p" (privileged) mode. When executed with the -p flag, ksniff will create a new pod on the remote kubernetes cluster that will have access to the node docker daemon.

ksniff will than use that pod to execute a container attached to the target container network namespace and perform the actual network capture.

Contribution

More than welcome! please don't hesitate to open bugs, questions, pull requests

Future Work

  1. Instead of uploading static tcpdump, use the future support of "kubectl debug" feature (https://github.com/kubernetes/community/pull/649) which should be a much cleaner solution.
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