Getting --link error

[digitaltim-de]

Docker 20.10.21 & 20.10.22:

Error:
dockerfile parse error line 23: Unknown flag: link

If i delete the --link tags it works.

Docker compose latest version 2.14.2 any idea why?

[maxhelias]

Your docker engine must be greater than 20.10.14

[maxhelias]

And if you want more information about the link option :

• https://docs.docker.com/engine/reference/builder/#copy---link
• https://www.howtogeek.com/devops/how-to-accelerate-docker-builds-and-optimize-caching-with-copy-link/

[TacoV]

The Docker Engine versions OP uses are greater than 20.10.14.
I am experiencing the same issue on Docker Engine 20.10.17.

Sending build context to Docker daemon  3.674kB
Sending build context to Docker daemon  3.674kB
2 errors occurred:
        * Error response from daemon: dockerfile parse error line 23: Unknown flag: link
        * Error response from daemon: dockerfile parse error line 23: Unknown flag: link

The trick was in the last link: "This feature is only available when using the BuildKit backend, and is ignored when using the classic builder backend."
After export DOCKER_BUILDKIT=1 it all worked as expected

[digitaltim-de]

Can confirm, that DOCKER_BUILDKIT fix it. So closed.