Ever needed to diagnose weird networking bugs on BOSH deployed VMs? We ran into a problem with a BOSH release that would create routes for itself on the networking stack. To detect this, Arpy was created.
Arpy is a simple bash script which uses the BOSH CLI and jq. The ip addresses of each of the vms in a particular deployment are looped through. An ssh session is established and an arping command is run against all the ip addresses in the deployment. You can quickly identify which virtual machines can (and importantly cannot) send and receive traffic.
Start by setting a few environment variables:
export BOSH_ENVIRONMENT="name of your bosh director"
export BOSH_DEPLOYMENT="name of your deployment"
Clone this repo and call the script to view the response. To see the results on the screen and dump them to a flat file run:
./arpy.sh 2>&1 | tee results.out