[mike_hearn]

It's worth noting that Docker was primarily a godsend for people working in scripting languages like Ruby or Python, where they have very messy packaging systems, depend on tons of native Linux libraries and so on.

For people working on the JVM the world was in some sense already 'drenched in light'. You could just send the sysadmin a fat jar you developed on Windows or macOS and tell them to deploy it, done. Or maybe you'd use an app server, so you'd send a less fat jar and they'd deploy it via a GUI and it already gets high level services like db connections, backups, message queues etc.

Also, Docker doesn't really solve the common case of an app that depends on a DB, maybe email etc. Those are services that need administration, you can't just start up a random server and expect things to go well. At least you need backups, proper access control and so on.

So deployment difficulty was very much dependent on what ecosystem you were in.

[tinco]

That's certainly true and describes my circumstances at the time. But it's also good to note that it is great for C/C++ dependencies as well, our GIS applications require PROJ, and our machine learning projects various Nvidia cuda things.

Also, just last week I needed new smbd features, and the only way to deploy a recent smbd version whilst retaining sanity seems on Ubuntu seems to be to just use docker. Normally there's a PPA but there wasn't in this case for some reason.