cnetstat dumps a list of TCP connections on a host, with their
Kubernetes container and pod names if they are from a container. It
currently assumes that the containers run on Docker, with labels in
the format that my version of Kubelet uses.
To get an x86-64 binary, download the latest release like this:
curl -L https://github.com/microsoft/cnetstat/releases/latest/download/cnetstat.x86_64 > cnetstat
Make it executable:
chmod +x ./cnetstat
and then run it like this:
sudo ./cnetstat
You should see output like this:
Namespace Pod Container Protocol Local Host Local Port Remote Host Remote Port Connection State
myapp frontend fe-server https aks-nodepool1-23 4592 10.2.9.76 https ESTABLISHED
myapp backend be-server https aks-nodepool1-23 6820 10.2.10.82 https ESTABLISHED
myapp backend log-scraper https aks-nodepool1-23 7819 10.2.9.83 https TIME_WAIT
If you want JSON output, try this:
sudo ./cnetstat --format=json
If you want to count connections per origin/destination pair, use the
--summaryStatistics option.
(To run on other architectures, you'll need to build from source. There are instructions in the contributing doc.
We built cnetstat to help figure out which containers in a Kubernetes cluster were using up TCP ports by opening lots of short-lived outbound connections.
You might want to use cnetstat if you have that problem, or any problem related to the interaction of container-level and host-level networking. We hope cnetstat will be helpful to you too.
See the design doc.
Is there a feature that would make cnetstat more useful for you? Are you hitting a bug? Is the documentation unclear or lacking? Please let us know!
See the contributing doc for the details.
Whether it's a feature, a bug report, or anything else, your contributions make cnetstat better for everyone. Thank you.