@girish Hi Girish! So I could totally be misreading this, but after some testing, it really does look like CPU and Mem stats do come through from the underlying host... Here is what I tried to confirm this. Let me know if I am way off base and I'm missing something crucial.
First, just base observations:
Prometheus reports back 4GB of total system memory, much more than the 512MB I have allocated for the Prometheus app container itself. Most of the time, the CPU utilization of my host VPS hovers around 2-3% as reported by Prometheus data, whereas the (according to Top) CPU utilization of the container is 1-2.5% Graphs on my VPS provider's control panel roughly correlate to the CPU utilization observed in Prometheus data.Second, based on stress-testing
Using Stress to stress-test individual CPUs or all CPUs to 100% in the host system correctly registers corresponding observations in Prometheus data. Using Stress -vm within the Prometheus app container to take up 256MB of RAM correctly registers a ~256MB bump over existing baseline memory observations from Prometheus data, and not 50+% utilization as would be expected if the container stats were being reported (container has 512MB allocated to it). Using Stress -vm out on the host system to chew up 2 GB of memory correctly shows a ~2GB increase in memory utilization reported by Prometheus data.So far CPU, Mem, and Network stats are all that I have played with, and Network is the only one so far that I can confirm positively does only report the container stats instead of the host system.
Not having correct network stats isn't a deal-breaker for me (though it would be nice, but not if doing so would put the system at risk of a container breach). I thought I'd at least report my findings thus far for anyone else that stumbles upon this.
Anyway, even if I am wrong, I have had a real great time playing with this! Thanks for making it all possible!
