chancez / capper

capper

Capper is a distributed tcpdump tool.

Use it to help you diagnose and troubleshoot network issues in your environments.

How it works

Using libpcap capper can capture packets just like tcpdump or Wireshark, but it offers a set of server components for remotely capturing packets.

The capper server component exposes a GRPC API which can be remotely queried using capper remote-capture.

You can also run the capper gateway which acts as a relay that federates queries to multiple capper servers, aggregates the results and streams them back to the client.

Features

• Timed captures, run a capture for a specified amount of time then automatically stop
• Limited captures. Specify a number of packets to capture before stopping
• Capture packets on hosts or in containers
• Supports targeting Kubernetes pods via containerd integration
• Support capturing from multiple interfaces

Planned features (in no particular order):

• Support targeting and capturing from multiple pods
• Support capturing by namespace without pod names
• Support capturing by pod labels/namespace labels
• Better default output (similar to tcpdump or tshark)
• Helm chart

Building

Building on Ubuntu:

Install Go and then run the following:

sudo apt install libpcap-dev build-essential
make

Deploy

kubectl apply -f k8s

Then to use it:

Usage

Open a connection to the gateway:

kubectl port-forward svc/capper-gateway 48999:48999

Then run:

./capper remote-capture

Or using docker:

docker run --privileged --net=host -v --rm -it ghcr.io/chancez/capper:latest remote-capture --server host.docker.internal:48999

Run capper --help for all possible commands, arguments, and flags. capper remote-capture and capper local-capture supports the basic options you would expect from tcpdump.

Demo