debugnotes

# Testing network services

  * One debugger driver driving the whole test
      - Unpacked image/tarball with distribution root
  * Driver creates one debugger for each namespace (or alternatively one debugger as part of the driver)
  * For each system
      - Unshare mount namespace
      - Use image/tarball file for lower dir (alternatively use current root)
      - Create tmpfs for upper dir (for changes)
      - Create workdir for overlayfs operation
      - OverlayFS using mount with lower, upper and workdir as options to new mount point
      - Use the new mount point for pivot_root, keeping the original root
      - You can use the original root for data, logs and more
      - Spawn all services to be debugged
  * For each debugger (alternatively for each debugged process)
      - Unshare network
  * For each debugger pair in debugger driver
      - Create veth and/or hwsim
      - Move those into namespaces by file descriptor for `os.open("/proc/$PID/ns/net")`

References:

https://github.com/dbecvarik/pycoz