It eliminates the dependency of specific distributions problem and, maybe more importantly, it solves the dependency of specific distribution versions problem (i.e. working fine now but might not work at all later in the very same distribution because some libraries are missing or default configuration is different).
For example, one of the games I have in my GOG library is over 10 years old and has a native Linux binary, which won’t work in a modern Debian-based distro by default because some of the libraries it requires aren’t installed (meanwhile, the Windows binary will work just fine with Wine). It would be kinda deluded to expect the devs would keep on updating the Linux native distro (or even the Windows one) for over a decade, whilst if it had been released as a Docker app, that would not be a problem.
So yeah, stuff like Docker does have a reasonable justification when it comes to isolating from some external dependencies which the application devs have no control over, especially when it comes to future-proofing your app: the Docker API itself needs to remain backwards compatible, but there is no requirement that the Linux distros are backwards compatible (something which would be much harder to guarantee).
Mind you, Docker and similar is a bit of a hack to solve a systemic (cultural even) problem in software development which is that devs don’t really do proper dependency management and just throw in everything and the kitchen sink in terms of external libraries (which then depend on external libraries which in turn depend on more external libraries) into the simplest of apps, but that’s a broader software development culture problem and most of present day developers only ever learned the “find some library that does what you need and add it to the list of dependencies of your build tool” way of programming.
I would love it if we solved what’s essentially the core Technical Architecture problem of in present day software development practices, but I have no idea how we can do so, hence the “hack” of things like Docker of pretty much including the whole runtime environment (funnilly enough, a variant of the old way of having your apps build statically with every dependency) to work around it.
It eliminates the dependency of specific distributions problem and, maybe more importantly, it solves the dependency of specific distribution versions problem (i.e. working fine now but might not work at all later in the very same distribution because some libraries are missing or default configuration is different).
For example, one of the games I have in my GOG library is over 10 years old and has a native Linux binary, which won’t work in a modern Debian-based distro by default because some of the libraries it requires aren’t installed (meanwhile, the Windows binary will work just fine with Wine). It would be kinda deluded to expect the devs would keep on updating the Linux native distro (or even the Windows one) for over a decade, whilst if it had been released as a Docker app, that would not be a problem.
So yeah, stuff like Docker does have a reasonable justification when it comes to isolating from some external dependencies which the application devs have no control over, especially when it comes to future-proofing your app: the Docker API itself needs to remain backwards compatible, but there is no requirement that the Linux distros are backwards compatible (something which would be much harder to guarantee).
Mind you, Docker and similar is a bit of a hack to solve a systemic (cultural even) problem in software development which is that devs don’t really do proper dependency management and just throw in everything and the kitchen sink in terms of external libraries (which then depend on external libraries which in turn depend on more external libraries) into the simplest of apps, but that’s a broader software development culture problem and most of present day developers only ever learned the “find some library that does what you need and add it to the list of dependencies of your build tool” way of programming.
I would love it if we solved what’s essentially the core Technical Architecture problem of in present day software development practices, but I have no idea how we can do so, hence the “hack” of things like Docker of pretty much including the whole runtime environment (funnilly enough, a variant of the old way of having your apps build statically with every dependency) to work around it.