ctl script should handle "onPrem" as well as "onPremise"

[SaxyPandaBear]

Describe the bug
Changing to use onPremise is a breaking change introduced in #417. The agent should accept the existing onPrem flag as well.

[khanhntd]

Personally, I would not prefer to add onPrem flag even though its breaking existing user's behavior because considering the scale of custom flag, we should reduce addition customer flags whenever its possible. However, this change indeed could break internal customer impacts after merging from live; but, I would say a more addressing-problem would be the breaking change's visibility regarding external and internal customer.

[SaxyPandaBear]

I should have pressed on this further in the original PR. What benefit is there in doing onPremise instead of onPrem?

The fact that the code in the ctl script used to contain:

     onPremise)
          param_mode="onPrem"
          ;;

makes me think that we should have never touched this. If we don't expect customers to run the translator themselves, there was no reason for us to touch any of these flags.

[khanhntd]

I would disagree with that. Because we expect customers to not run the translator themselves; therefore, we should change the internal flow as smooth as possible. Such as the mentioned PR, why it should change mode from onPremise to onPrem only to adapt the translator and the downloader? Does every time we make a new custom flag, we should change the internal components as well or is this an exception? I would prefer more consistent flag between these components; and I would also say its because the existing customer's behavior does not mean its good though (same as DockerShim drawback for maintainability)

[SaxyPandaBear]

same as DockerShim drawback for maintainability

It's not the same though. Kubernetes announced that they were deprecating Dockershim support in k8s in a blog on December 2, 2020. https://kubernetes.io/blog/2020/12/02/dont-panic-kubernetes-and-docker/

They gave almost 1.5 years since the announcement in 2020 until the v1.24 release of k8s which actually removes the Docker support. https://kubernetes.io/releases/#release-v1-24

What we did was completely pull out the old flag without any announcement or transition period. This is bad user experience all across the board and is not an acceptable way to introduce a breaking change.

[SaxyPandaBear]

Done as part of #543