One of the tenants of building Docker containers is to keep them small and lean. In some cases, this can limit your troubleshooting options as the containers won't have many of the common Linux networking tools as part of their image. While not ideal, it is sometimes nice to have a container image that has these tools installed so that you can troubleshoot the network from the container perspective. In this chapter, we'll review how to build a Docker image specifically for this purpose.
In this recipe, we'll be using a single Docker network host. It is assumed that Docker is installed and in its default configuration. You'll also need root-level access in order to inspect and change the hosts networking and firewall configuration.