Add netcat into the image

[samuel-deal-tisseo]

Hello.

I've read the issue #326 and I understand why there is no official health-check.
However, I think it netcat should be included inside the image to allow users to set a simple nc -z localhost 5672 healthcheck when then want it without having to build a custom image.

Thank you

[lukebakken]

Hello, thanks for using RabbitMQ.

Docker makes it so easy to add netcat yourself that it will not be considered here. Only utilities necessary to run RabbitMQ are included in these images.

[michaelklishin]

nc -z localhost 5672

is not meaningfully different from

rabbitmq-diagnostics check_port_connectivity -q

and just like that health check, it has one major problem: the node may or may not be accessible at localhost, or from a remote node if you run rabbitmq-diagnostics command there.

Instead of gathering information from GitHub issues, I'd consult the official doc guide on Monitoring and Health checks.