I have been working with docker version 18.02 building images locally. Now, I need to work with Openshift3.11 which run docker version 1.13. I just wondering if my images build locally be compatible and run in Openshift3.11.
More generally, what is the compatibility level/restrictions for images built by different version of docker engine? How to understand it? Thanks.
I just wondering if my images build locally be compatible and run in Openshift3.11
As I have been working for couple of years with Openshift, from 3.2 to 3.11, I can give some info on this
Here is the docker version that we use currently
$ docker --version
Docker version 19.03.1, build 74b1e89
As stated by you Openshift 3.11 needs docker version with 1.13.1, but this won't stop you deploying images that were built with newer versions of docker.
We were using Docker 18.*, earlier while deploying it to Openshift 3.2 and 3.9. But haven't faced any issues so far with the compatibility of Docker images.
For some more info on docker compatibility - https://success.docker.com/article/compatibility-matrix
If we check some of docker release notes/blogs we do see that major changes were in either security/fixes/features or something more related to docker swarm.
For example, from docker release 1.13
Benefits include:
Specifying the number of desired instances for each service
Rolling update policies
Service constraints
Clean-up commands
Docker 1.13 introduces a couple of nifty commands to help users understand how much disk space Docker is using, and help remove unused data.
docker system df -- will show used space, similar to the unix tool df
docker system prune -- will remove all unused data.
Some more info on release 1.13 and release 1.19
So as a whole, building images and running containers remain the same irrespective of docker version we use, if the underlying command/concepts are the same in both the versions.
Hope this helps!
