Introduce docker-based web monitoring system

We have around twenty websites and services out on the web. I need a monitoring system to monitor all these services (mostly http/https, but others like mail servers should be possible). Must-haves: - frequently check if the service is reachable - check if the http status is OK (not 404/50x or something like that) - host health checks (free disk space, memory usage, load etc.), all are linux machines, mostly docker hosts - alert via email if something is off - alert via SMS Nice-to-haves: - do some content checking for websites (I could provide some information in the config, so the system can see if it gets the right page, maybe there exist even better approaches) - check if ssl certificates have a remaining life team of at least 14 days Please state in your offer which nice-to-have-points you can do and if there is an additional price for them. All this should have a simple to use web interface. The software used should be under active development and OPEN SOURCE. It should run on a docker host within one or more docker containers (maybe one database container and one container for the monitoring server). I would prefer using something from docker hub that seems to be under active development, so I have a good starting point if I want to upgrade later. But if you have good arguments against this, I'm open to here them :-) What you have to do: - give me an installation instruction for running the docker containers for the monitoring system - step-by-step guidance on configuring the hosts/services - help me if I have questions about the installation within 7 days after everything is done I am an experienced software developer and I very ofter work on the shell. But I do not have the time to read the manual, but want a tailor-made solution for what I've described above. The above mentioned nice-to-have-points can also be added later on when the core system is running fine.