Don’t be surprise. It is very natural movement from monolithic style to MSA. And it is not sooner issue. Just happen to late 2021 as a plan. And most of customer doesn’t impact your system. Due to many of service provider (GCP, AWS, AZURE, OpenShift, RKE and so on) already change their Container Runtime from (a little noisy?) old version of docker to light Container Runtime. I.e. new version of docker or others. And also it is no no no impact to your current image because you already use containerD monstly and what if you use old version of docker and also k8s said support old dockershim with there supportive method.

1. The Myths of deprecating Docker in kubernetes.
This document provides for customer and eco partenr for understanding docker in k8s.
- Email: hj@mz.co.kr, geunwoo.j.shim@gmail.com
- Github: https://github.com/sysnet4admin, https://github.com/gnu-gnu
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the
following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial
portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT
OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE. Copyright <2020>

2. !"#$%&'()&*+#,-&').*#)&#/01#
There is many of Container Runtime could integrated with k8s cluster. K8s is eager to be
standard to connect from other. Like module.
Here is official Container Runtimes in k8s document.
https://kubernetes.io/ko/docs/setup/production-environment/container-runtimes/
2#3)4#5!#$%&'()&*+#,-&').*1#6%+#/01#7#

3. 8"#$%&'()&*+#,-&').*#9*+1)%&#4:(&;*.*&'###
Here is chagement per each of version. So, this changement will remove dockershim and
isolate each of component and dedicate them for own purpose.
[ Pic #2 docker -> containerD ]
See more detail about it.
[ Pic #3 docker -> containerD with kubelet ]
(Docker CE 18.03)
(Docker CE 18.06)

4. 8"#<*'=**&#/01#(&>#4%&'()&*+?#)&#':*#@%%/#ABCD#8E8!#8FG#
ContainerD is not ‘must choose’. It is optional value. And dockershim go away BYE BYE
2#3)4#5H#>%4/*+#)&#/01#7#
2#3)4#5I#4%&'()&*+?#3)J*K)&*#7#
#
L"#CMN#?,#
Don’t be surprise. It is very natural movement from monolithic style to MSA. And it is not
sooner issue. Just happen to late 2021 as a plan. And most of customer doesn’t impact your
system. Due to many of service provider (GCP, AWS, AZURE, OpenShift, RKE and so on)
already change their Container Runtime from (a little noisy?) old version of docker to light
Container Runtime. I.e. new version of docker or others. And also it is no no no impact to
your current image because you already use containerD monstly and what if you use old
version of docker and also k8s said support old dockershim with there supportive method.
Thus, you do not worry about it. It is CNCF!! J Gotcha!
(‘Kubernetes administrators will be able to use dockershim in future. Keep an eye on the
Mirantis and Docker blogs for updated information about the future of dockershim and how
to install the standalone shim.’)
Reference:
1. https://kubernetes.io/blog/2020/12/02/dont-panic-kubernetes-and-docker/
2. https://kubernetes.io/blog/2020/12/02/dockershim-faq/
See ya!
Hoon Jo & gnu.