> a better alternative would instead be something akin to Dockerfiles where you assert what packages you want to be installed on top of a base system, and if you want anything changed you update the dockerfile and rebuild the whole shebang.
Something like Packer?
You are right that there are hidden pitfalls. But they shouldn't be a great deal if servers are cattle. A lot of corner cases are related to trying to manage servers that live forever. This shouldn't really be done in 2021 except in rare cases.
> i'm imagining a system where the local filesystem is more or less immutable and work is saved to separate filesystem
CoreOS worked like that. Immutable filesystem for the system itself. It also had a secondary "mirror" of this filesystem that was used for upgrades (and as a fallback in case boot failed). New stuff would either come when the instance first booted up (cloud-init), or via system upgrades.
They were acquired and so my experience with them ended there.
Something like Packer?
You are right that there are hidden pitfalls. But they shouldn't be a great deal if servers are cattle. A lot of corner cases are related to trying to manage servers that live forever. This shouldn't really be done in 2021 except in rare cases.
> i'm imagining a system where the local filesystem is more or less immutable and work is saved to separate filesystem
CoreOS worked like that. Immutable filesystem for the system itself. It also had a secondary "mirror" of this filesystem that was used for upgrades (and as a fallback in case boot failed). New stuff would either come when the instance first booted up (cloud-init), or via system upgrades.
They were acquired and so my experience with them ended there.
There's also https://nixos.org/