as someone in almost the same situation (about 50 instances), but chose to go with docker, I just want to say you made the right choice. Of course a few years

as someone in almost the same situation (about 50 instances), but chose to go with docker, I just want to say you made the right choice. Of course a few years ago, being young and a one man ops team, I wanted to use the cool new thing and so did everyone else. I went with Ansible after being a Chef guy for a while due to ease of getting started. That was the easy part. Love Ansible, but it was slow to get new Docker functionality for a while, and not having the built in functionality of having Chef runs happening periodically without paying for Tower means I have to be more mindful and deliberate with keeping my infra in sync and up to date. Enter Docker and months and months of headaches just to get something usable on the local workstation level. So much wasted time dealing with breaking changes and figuring out exactly which version to use and very rarely upgrading. Debugging and troubleshooting becomes an unintuitive nightmare. Even after all that, our site still ended up running really slow locally in Docker. This is because with apps (such as CMS) that handle many, many files, I/O slows wayyy down. Ended up discovering Dinghy (shout out to codekitchen) and got it to a decent state (but make sure developers don't accidentally install Docker for Mac as it is and always has been a CPU gobbling mess). Then on top of that there is the container orchestration (consul-template), monitoring (Prometheus is cool, but takes a bit to understand what is needed to get the metrics you want), logging (fluentd is again, cool, but oh man is parsing logs a PITA to understand), debugging tools etc. I can't even imagine what adding k8 on top of the many quirks of Docker would mean. I luckily took one look at needing a whole zookeeper cluster just to get started, and immediately gave up on that.