dnsmasq is run inside the container with output sent to stdout. But the container is run detached and so the logs are not captured. Docker provides configurable ways to capture the logs. We should capture them via `json-file` and then output the logs on failure or success.

References:
https://docs.docker.com/config/containers/logging/json-file/
https://docs.docker.com/config/containers/logging/plugins/
https://docs.docker.com/config/containers/logging/configure/