According to the release schedule, the slightly delayed version 1.24 of Kubernetes is expected to be officially released on May 3; This version contains a major change, that is, the built-in support for dockership will be completely removed. If you Use Docker Engine as When the container of Kubernetes cluster is running, it needs to be ready for migration in 1.24. To check if you are affected, see Check whether dockership abandonment affects you 。
Officially In December 2020 Officially announced The dockership will be abandoned by and is expected to be It will be officially removed when Kubernetes 1.24 is released in April 2022 。 According to the announcement, Maintaining dockership has become a heavy burden for Kubernetes maintainers.
according to introduce ， Docker is the first container runtime used by Kubernetes. However, as the Kubernetes project is transitioning to its own Open Container Initiative (OCI), it needs an expedient plan to realize the migration with other container runtimes; The expedient is dockership. In essence, dockership was originally used as a temporary solution (hence its name: shim ）The popular Docker Engine container runtime is allowed to convert OCI calls into Docker calls within Kubernetes' own container runtime interface (CRI).
As time goes by, dockership becomes deep-rooted in Kubernetes deployment, but it slows down the deployment speed and brings burden to maintainers; Therefore, it is inevitable to be eliminated. In addition, functions that are basically incompatible with dockership (such as cgroups v2 and user namespaces) are also being implemented in newer CRI operating systems; Removing support for dockership will allow further development in these areas.
"Dockership has become an anomaly in the Kubernetes project. The dependence on Docker and Dockership has penetrated into various tools and projects in the CNCF ecosystem, resulting in code vulnerability."
Developers who do not use CRI compliant runtime to replace dockership may destroy their clusters, not get timely security patch updates, and also miss new functions. The Kubernetes team posted a blog in January express At present, more and more cluster operators have switched to Other container runtime. "We believe there is no major obstacle to migration. The steps we take to improve the migration experience will point out a clearer path for you... We believe that the value you (and Kubernetes) gain from removing dockership can make up for your migration work."
Developers can still use Docker locally to develop or test their containers, no matter which container runtime they use for the Kubernetes cluster. Docker produced images will continue to work in all CRI compliant runtimes clusters, but will not continue to be supported.
