Please consider this chart a moment; it shows the different hosting models common today:

[![enter image description here](https://i.stack.imgur.com/ehcV1.png)](https://i.stack.imgur.com/ehcV1.png)

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From the chart I learn that CaaS, PaaS and FaaS are three hosting-models by which a user can't control the OS it gets (as the OS of its server environment - webserver, email server and whatever-else-server leaning on the internet).

But I wonder how can a client for a CaaS/PaaS/FaaS service actually know if the operating system of their server environment is **really of the newest version in every possible manner**.

I wonder what ways I have as a customer to ensure a CaaS/PaaS/FaaS company won't literally lie to me when they report "Your Debian is latest" (say Debian 9 or 10 (that should come out soon, or 11 or 12), or "Your ArchLinux is latest" and so on and so forth.

In all three I can automate everything above the OS with Ansible but that still doesn't make me quiet in my mind; I'm still "anxious" regarding my OS; I desire all its upgrades to be fully automated as well.

**What tools should I have in my environment** (a CLI terminal wouldn't necessarily be enough here by itself) to actually really know if they report the truth and not plain lying to me regarding the OS version (minor, major, and release)?

Although a bit old (say 4-8 years) OS can be stable in relation to all up2date software above it, I would still prefer to be up2date in everything, if circumstances allow it (till now I had 5$-30$ IaaS VPSs on DigitalOcean).