Not every module contributes to every runtime.

The core-runtime module defines each runtime:

- The target JVM for the runtime. Each runtime has its own JVM compatibility constraints.
- Some base services that are available to code hosted by the runtime. This varies by runtime.
- Additional constraints. For example, the CLI client runtimes limit the libraries that are available to the code in that runtime, for performance reasons. 

This platform does not provide special support for a particular kind of automation. This is the responsibility of other platforms.

It is made up of 3 architecture modules:

- **core-runtime**: Provides the runtimes or "containers" in which code runs. These runtimes include the Gradle client, the daemon and the worker processes. This is the base module on which all other architecture modules depend.

When working on some source code it is important to be aware of the runtimes in which it will run, so that you don't break these constraints.
There is some assistance in the IDE for this plus a lot of validation that is applied at build time and on CI, but it is useful to keep these constraints in mind as well.

See [Gradle runtimes](runtimes.md) for a list of these runtimes and more details.

### Build execution model

This platform does not provide special support for a particular kind of automation. This is the responsibility of other platforms. 

It is made up of 3 architecture modules:

- **Runtime**: Provides the runtimes or "containers" in which code runs. These runtimes include the Gradle client, the daemon and the worker processes. This is the base module on which all other architecture modules depend.

* Fixed a panic in `kubectl run --attach ...` when the api server failed to create the runtime object (due to name conflict, PSP restriction, etc.) ([#61713](https://github.com/kubernetes/kubernetes/pull/61713), [@mountkin](https://github.com/mountkin))

  - [alpha] Introducing the v1alpha1 CRI API to allow pluggable container runtimes; an experimental docker-CRI integration is ready for testing and feedback. ([docs](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-node/container-runtime-interface.md)) ([kubernetes/features#54](https://github.com/kubernetes...

    * Rebase image on debian-base:v1.0.0
* If a pod has a running instance, the stats of its previously terminated instances will not show up in the kubelet summary stats any more for CRI runtimes like containerd and cri-o. ([#77426](https://github.com/kubernetes/kubernetes/pull/77426), [@Random-Liu](https://github.com/Random-Liu))

* Kubelet now proxies container streaming between apiserver and container runtime. The connection between kubelet and apiserver is authenticated. Container runtime should change streaming server to serve on localhost, to make the connection between kubelet and container runtime local. ([#64006](https://github.com/kubernetes/kubernetes/pull/64006), [@Random-Liu](https://github.com/Random-Liu))

From v1.24 onwards, you will need to either use one of the other [supported runtimes](https://kubernetes.io/docs/setup/production-environment/container-runtimes/) (such as containerd or CRI-O)
or use cri-dockerd if you are relying on Docker Engine as your container runtime.
For more information about ensuring your cluster is ready for this removal, please

cgroupDriver value in the KubeletConfiguration is now always set to "systemd" unless the user is explicit about it. This requires existing machine setups to configure the container runtime to use the "systemd" driver. Documentation on this topic can be found here: https://kubernetes.io/docs/setup/production-environment/container-runtimes/. When upgrading existing clusters / nodes using "kubeadm upgrade" the old cgroupDriver value is preserved, but in 1.22 this change will also apply to "upgrade". For more...