How to get info about the bridged interface of a node?

[chlohr]

Related Bug

No response

Feature Description

Hello,
Let'say I've started a node with: kathara vstart --eth 0:A --bridged -n pc1
What should I do to get IP of this bridged interface ?
Something answering "Hey, node pc1 is at 172.17.0.2"
Many thanks!
Regards

Solution

No response

Alternative Solutions

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Additional Context

No response

[Skazza94]

Hi @chlohr,
Kathará does not directly manage the Layer3 of the network (it is set up by the user through the startup files and Docker).
Therefore, there is no straightforward way to know the bridged IP address from Kathará.

You need to "ask" the device about the IP address.

If you know the eth number, for example eth3, you can obtain the IP address by running:

kathara exec <device_name> -- ip addr show dev eth3

If you need a machine-readable output, you can try the following:

kathara exec <device_name> -- ip -j addr show dev eth3

Will give you a JSON output.

[chlohr]

Many thanks for your message.

I guess the right way to do this is to ask Docker:

docker inspect ` kathara linfo -n pc1 | sed -ne 's,.*Container Name: \(.*\) .*,\1,p' ` | jq -r '.[0].NetworkSettings.Networks.bridge.IPAddress'

But this is rather complex. Is there a more simple way?

[chlohr]

Another suggestion (not necessarily simpler):

 docker inspect --format='{{println .NetworkSettings.Networks.bridge.IPAddress}}' `docker ps --filter 'label=name=pc1' --format '{{.ID}}'`

[Skazza94]

Hi @chlohr,
both your solutions are fine.

But this is rather complex. Is there a more simple way?

As I already mentioned before, Kathará does not handle the IP stack (even if the bridged is managed by Docker). Therefore we do not expose any API to retrieve IP addresses (which might also be unassigned to interfaces).