[GregorStocks]

When you're managing more than a handful of servers, you very quickly start wanting to be able to run the same command on multiple machines - "upgrade all my API boxes to the not-vulnerable nginx", for instance, or "push this binary out to all my database servers". These sorts of services make that straightforward, and generally provide a large library of prewritten modules to do moderately-complicated things without having to write a lot of boilerplate or read somebody else's Bash scripts or Perl.

[tootie]

Well, I've done that just using remote shell commands. And I'd have an easier time reading someone else's bash than I would their ansible whatevers. Is it actually more concise?

[eropple]

When written correctly, it's idempotent. I've done a lot of server management with bash and it's a lot easier to achieve idempotency with something like Chef.

[crdoconnor]

It's usually more concise because idempotency comes by default. Instead of saying "create this file" (which might throw a 'file already exists' error the 2nd time you run the setup script), you say "ensure this file exists".

Some bash commands are idempotent too (e.g. apt-get install), but it's not something you can rely upon, and you often have to code the idempotency in yourself.

[rb2k_]

What if you have to upgrade a software package and add a new config file that is different on every server. I guess you can do that via a horrible sed command, but having native template support with variables is pretty nice.

Same for things like "tune the amount of worker processes depending on the amount of CPU cores the machine in question has".

[ayrx]

Things like Ansible/Salt and similar tools cut out a lot of the boilerplate. There are also plenty of modules you can reuse without having to roll your own. You can achieve the same results using Bash/Perl/Python but a lot more effort is needed.