NIFI-7192 - nifi.sh install not working on systemd servers

[rmarturano]

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Description of PR

After invoking nifi.sh install, systemd manager configuration is reloaded. In this way, wrapper from init.d to systemd service is generated and the service will work smoothly. Fixes bug NIFI-7192.

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[rmarturano]

@pvillard31 / @alopresto can you please take a look on this?

[jfrazee]

@rmarturano For due diligence, what distributions has this been tested against? I have two worries with this: (1) that the commands might not always be on the path and (2) that using pidof might not be reliable.

I think it might be worthwhile to add some additional checks (e.g., what's mentioned by https://www.freedesktop.org/software/systemd/man/sd_booted.html).

[jfrazee]

@rmarturano Do you still want to see this go in?

[rmarturano]

@jfrazee @exceptionfactory first of all thanks for your inputs.
I applied suggested changes and rebased.

[github-actions]

We're marking this PR as stale due to lack of updates in the past few months. If after another couple of weeks the stale label has not been removed this PR will be closed. This stale marker and eventual auto close does not indicate a judgement of the PR just lack of reviewer bandwidth and helps us keep the PR queue more manageable. If you would like this PR re-opened you can do so and a committer can remove the stale tag. Or you can open a new PR. Try to help review other PRs to increase PR review bandwidth which in turn helps yours.

[rmarturano]

@jfrazee Shall we merge it?

[MikeThomsen]

@jfrazee why did you hold off on merge after approving? Was more work required?

[jfrazee]

@MikeThomsen Was just trying to snag some time to test on something besides Ubuntu. I validated it on Ubuntu 20.04 and OpenSuSE 15.3. This fix works as expected for both.

There was a wrinkle with OpenSuSE -- they removed the rc*.d dirs entirely now so need to open another issue for that. This doesn't have anything to do with this PR though so merged.

Thanks @rmarturano