You'd be surprised. Big Java enterprise apps deployed to Tomcat or God-forbid! IBM/Oracle app servers can take 2-3-5 minutes just to be fully operational. I've had deployment health checkers timeout after 2 minutes because the servers just wouldn't be up. It seems insane, but that's how life looks for thousands of developers.
> It seems insane, but that's how life looks for thousands of developers.
True, but there's tens of thousands of developers not using big Java enterprise apps where having Docker add 4-5-6+ seconds of startup time has a huge negative impact.
gunicorn (Python) apps tend to start in hundreds of milliseconds (even pretty big ones).
puma (Ruby) apps tend to start in seconds or tens of seconds (it can get higher for massive apps).
cowboy (Elixir) apps tend to start in low seconds (this includes booting up the BEAM VM).
Just the above 3 examples cover the Flask, Django, Rails and Phoenix ecosystem. That's a lot of developers.
One app I work with has 40 top level gems and about 17,000 lines of Ruby code (which goes a longs ways in Rails). It's not "big big" but it's not tiny. It takes under 10s to boot up. I'm sure if you have a Shopify-tier app it takes much longer, but a majority of apps aren't at that scale.
I was just throwing out examples and I'm just trying to say not everyone is dealing with cases where Docker's added 2-5+ seconds isn't a big deal. For a Flask app those few seconds make it ~20-50x longer to start up due to Docker and for a majority of other frameworks / average app sizes, it's a non-ignorable amount.
