[chubot]

Just to double-click on container technology, why do you think it took so long for this technology that was built into Solaris to become mainstream with Docker?

I think VMWare deserves a mention here? And the terms OS Virtualization vs Hardware virtualization do as well (Ctrl-F doesn't find them.)

For awhile hardware virtualization (VMWare) was more prevalent, but it's more complex and has more overhead than OS virtualization (containers). That is how people solved the problem of having powerful machines and small workloads (or workloads with a lot of variance).

Although historically it might have been that hardware virtualization actually came first, in IBM mainframes. In the Unix world I guess OS virtualization came first.

[kakwa_]

I think docker succeeded not because it was a better container or virtualization solution, or because it was lighter than VMs. Jails or Solaris zones have existed for years or decades, and on Linux, we had openvz and vserver long before Docker. And I'm not even mentioning plain old chroot (with indeed some security issues).

I didn't follow the latest development, but for a while, Docker was not even that great in term of robustness and stability. I never was a big fan of the userland proxy for example. And from what I've read, upgrading from one docker version to another could be quite painful (disclaimer: I toyed with docker a little, I haven't used it in production yet).

IMHO, Docker succeeded because it brought a complete ecosystem around containers:

* Ways to generate the container image through Dockerfile

* Ways to compose an image on top of another (itself on top of another, etc...)

* Ways to share and distribute these images with Docker Registry