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Read about this over on Twitter: https://twitter.com/Dixie3Flatline/status/1334188913724850177?s=19 https://twitter.com/Dixie3Flatline/status/133418891372485017

Read about this over on Twitter: https://twitter.com/Dixie3Flatline/status/1334188913724850177?s=19 https://twitter.com/Dixie3Flatline/status/133418891372485017... The only "official" notice about it so far seems to be in the linked changelog.

boberoni 6y ago
This was very useful. Thanks for sharing. It seems that Docker images will still run fine on k8s. The main change is that they're moving away from the "Docker runtime", which is supposed to be installed on each of the nodes in your cluster. More details about k8s container runtimes here: https://kubernetes.io/docs/setup/production-environment/container-runtimes/ https://kubernetes.io/docs/setup/production-environment/cont...
- jsmith45 6y ago
  Right. The simplest option is to use containerd, as the runtime. Installing docker will also install containerd (because docker uses it internally), so nothing much needs to change except a configuration option. docker and k8s can run side by side sharing the same containerd instance, in case you need to do something like build containers inside your k8s cluster. You lose out on things that require access to the docker daemon socket, but ideally any such software should be replaced with something that talks with the kubernetes API instead. (exception is building containers in cluster. If you need that, run docker side by side with the kubelet, or use buildkit with containerd integration). You also lose the ability to interact with containers with the docker cli tool. Use crictl instead, which has most of the same commands, but also includes certain k8s relevant information in output tables.
- ccmcarey 6y ago
  Yep, they're not really "Docker" images. A while ago the image/container formats were standardized through the OCI.
fhrow4484 6y ago
The twitter thread has way more details about the change, which is why I submitted it here: https://news.ycombinator.com/item?id=25279424 https://news.ycombinator.com/item?id=25279424 https://twitter.com/IanColdwater/status/1334149283449352200 https://twitter.com/IanColdwater/status/1334149283449352200 also has some details
shuuji3 6y ago
There are several official responses now to help us understand this deprecation. K8sContributors on Twitter: "#Kubernetes 1.20 introduces an important change to the kubelet - the deprecation of #Docker as a container runtime option. What does this mean and why is it happening? You can learn more in our blog post! https://t.co/lzPPzwXUNM https://t.co/lzPPzwXUNM" / Twitter - https://twitter.com/K8sContributors/status/1334301732830990336 https://twitter.com/K8sContributors/status/13343017328309903... Don't Panic: Kubernetes and Docker | Kubernetes - https://kubernetes.io/blog/2020/12/02/dont-panic-kubernetes-and-docker/ https://kubernetes.io/blog/2020/12/02/dont-panic-kubernetes-... Dockershim Deprecation FAQ | Kubernetes - https://kubernetes.io/blog/2020/12/02/dockershim-faq/ https://kubernetes.io/blog/2020/12/02/dockershim-faq/

boberoni 6y ago

This was very useful. Thanks for sharing. It seems that Docker images will still run fine on k8s. The main change is that they're moving away from the "Docker runtime", which is supposed to be installed on each of the nodes in your cluster. More details about k8s container runtimes here: https://kubernetes.io/docs/setup/production-environment/container-runtimes/ https://kubernetes.io/docs/setup/production-environment/cont...

jsmith45 6y ago
Right. The simplest option is to use containerd, as the runtime. Installing docker will also install containerd (because docker uses it internally), so nothing much needs to change except a configuration option. docker and k8s can run side by side sharing the same containerd instance, in case you need to do something like build containers inside your k8s cluster. You lose out on things that require access to the docker daemon socket, but ideally any such software should be replaced with something that talks with the kubernetes API instead. (exception is building containers in cluster. If you need that, run docker side by side with the kubelet, or use buildkit with containerd integration). You also lose the ability to interact with containers with the docker cli tool. Use crictl instead, which has most of the same commands, but also includes certain k8s relevant information in output tables.
ccmcarey 6y ago
Yep, they're not really "Docker" images. A while ago the image/container formats were standardized through the OCI.

fhrow4484 6y ago

The twitter thread has way more details about the change, which is why I submitted it here: https://news.ycombinator.com/item?id=25279424 https://news.ycombinator.com/item?id=25279424 https://twitter.com/IanColdwater/status/1334149283449352200 https://twitter.com/IanColdwater/status/1334149283449352200 also has some details

shuuji3 6y ago

There are several official responses now to help us understand this deprecation. K8sContributors on Twitter: "#Kubernetes 1.20 introduces an important change to the kubelet - the deprecation of #Docker as a container runtime option. What does this mean and why is it happening? You can learn more in our blog post! https://t.co/lzPPzwXUNM https://t.co/lzPPzwXUNM" / Twitter - https://twitter.com/K8sContributors/status/1334301732830990336 https://twitter.com/K8sContributors/status/13343017328309903... Don't Panic: Kubernetes and Docker | Kubernetes - https://kubernetes.io/blog/2020/12/02/dont-panic-kubernetes-and-docker/ https://kubernetes.io/blog/2020/12/02/dont-panic-kubernetes-... Dockershim Deprecation FAQ | Kubernetes - https://kubernetes.io/blog/2020/12/02/dockershim-faq/ https://kubernetes.io/blog/2020/12/02/dockershim-faq/