Rudder tools

Following #14276, there are some adaptation needed to totally support Docker for Rudder

Agent¶

We need for the agent to detect that it is running within Docker - correct way seems to be https://stackoverflow.com/questions/20010199/how-to-determine-if-a-process-runs-inside-lxc-docker
Inventory should be augmented to have docker also

Services¶

systemctl doesn't exists within docker, so we need a way to start/stop/check services (S6 or equivalent)
We need to adapt techniques, generic methods and scripts (rudder agent check) to support this service management method

dependencies/volumes¶

identify the volumes and files to share - postgresl, ldap, config files statics
caution to data corruption when shutting down container

packaging¶

Need to automatically detect the version of the data used, and update them if necessary - some of these tasks are in packaging, here they need to be outsourced in a script and automatically run at the start of container
rational is: data are static, container can change versions outside of the data

And pleinty others