1.0 was released in 2015. There are stable LTS vendors for it.

It's pretty established. And much saner than cobbling together Ansible/Puppet/Chef playbooks for everything.

Saying that 2021's Kubernetes is established because 1.0 was released in 2015 is like saying that 1991's Linux is stable because Unix had existed for 20 years at that point. Kubernetes 1.0 and 1.20 share the same name, design principles and a certain amount of API compatibility, but it's impossible to take a nontrivial application running on 1.20 and just `kubectl apply` it on 1.0. Too much has changed.

Kubernetes is just now entering the realm of "becoming stable". Maybe in five years or so it'll finally be boring (in the best sense of the word) like Postgres.

Of course 1.20 has a myriad of additional featues. But 1.0 concepts are in 1.20, the fundamentals are stable. Schedule and run containers, expose them to the external network via a load balancer (or node port).

The declarative aspect is stable. Yes, many people are writing insane go programs to emit templated ksonnet or whatever that itself has a lot of bash embedded, but that's the equivalent of putting too much bash into the aforementioned configuration/orchestration playbooks.

Playbooks are terrible. They are a replacement for expert knowledge of platform tooling. There is no replacement for expertise and knowledge of the platform.

Serious problems are always reduced to understanding the platform, not the playbook. Ansible and the python ecosystem are especially broken. I will _never_ use another playbook to replace mature ssh driven deployments.

Yep, agreed. I found that the active control loops (coupled with the forgiving "just crashloop until our dependencies are up" approach) that k8s provides/promotes are the only sane way to ensure complex deployments. (The concepts could be used to create a new config management platform, but it would be really hard, as most of the building blocks are not idempotent, and making them such usually requires wrapping them and combining them with very I/O and CPU heavy reset/undo operations, blowing caches and basically starting from scratch.)

Hmm. The expectations and engineering of a platform like kubernetes and 'fail till right' require a lot of alignment work to get to the point where 'fail till right' works.

There is no silver bullet. Automation and self healing is a selling point but when it hits engineering it usually is a dud in terms of incorporation in existing environments.

The real novelty would be to generate a declarative description from the customer and provide an in place deployment solution via k8s. That would be the ultimate replacement solution.

I think what they may mean is more that there is an established platform within the organization. One that you have expertise and experience with, monitoring/backup/security tools that work with it, etc. K8s might not have as long a pedigree as VMs, but if you already have a setup to run K8s, people who know how to use it, documentation and tooling that allow devs to run their apps on it securely and efficiently, etc. it's pretty reasonable to want to encourage devs to "just" use k8s it if they want to stand up a new service rather than spinning up whatever random collection of technologies that dev happens to know better.

Well, firstly, the core components of k8s are pretty well understood now, and the APIs to them are not just going to change overnight.

Secondly, it doesn't really matter how old the platform is. As I said, it comes down to how familiar the operations team are with it. If you are running an on-premise or hybrid cloud, ops will want something familiar over all environments. They're not going to be happy with k8s on one, ansible on another, etc.