Why would you assume Alpine is only used for containers? I use it for my own local home server, as it's very lightweight and easy to tweak to how I want it.
Sadly when playing the CVE game, Debian containers are no contest to alpine.
For CentOS in a container I can see absolutely no reasons except if the SW is only tested against it.
To make sure that once services are up and running, they keep running and are restarted automatically? To have good, centralized logging? To manage in-container services the same way you do on the container host?
There's plenty of good reasons for one to want to do so.
I think it is counter to best practices to run multiple services in a single container. Although maybe you just need to with some proprietary software.
I still think that orchestration should live outside containers, whether within one box or several. BTW systemd has some vestiges of container orchestration built in.
OTOH there are other approaches; say, LXD directly assumes an ecosystem of processes within a container, more akin to a VM than to a single chroot-ed / jailed service process.
> OTOH there are other approaches; say, LXD directly assumes an ecosystem of processes within a container, more akin to a VM than to a single chroot-ed / jailed service process.
Those are what I had in mind. Basically cheaper VPS like service but built on Linux container tech instead of full virtualization. Maybe they are less of a rage these days, when fully virtualized KVM/Vmware VPS are so cheap. But about 5 years ago I did run my email server, webserver and database on such a container for $1-1.5$/mo. When I was able to switch to full virtualization at similar price point, I did. But there's nothing weird about runing multiple different processes in a "container" :)