If CompactionCoordinator dies, external compactions monitor page becomes stuck

[DomGarguilo]

One thing that I thought of, that I'm not sure how we want to handle, is if the page is refreshed, the banner indicating "Compaction Coordinator Not Running" shows up. But it doesn't appear that this will ever happen automatically via auto-refresh and will only show up on a full page reload.

Originally posted by @DomGarguilo in #3057 (comment)

Another bug that might be more relevant but is caused by the same thing is when the CompactionCoordinator dies, the tables that track it and the other external compaction tables will stay on screen without any change in data. This happens because the source that the tables pull from results in an error being thrown which blocks the datatables code and keeps them as-is.

I think to fix these issues we need to move the following functionality, which checks if the CompactionCoordinator is running into the javascript code so we can handle this case and avoid having to manually refresh the page:

accumulo/server/monitor/src/main/resources/org/apache/accumulo/monitor/templates/ec.ftl

Line 26 in 5c870af

<#if coordinatorRunning == true>

[ctubbsii]

@DomGarguilo This ticket was marked to be fixed for 2.1.1, because the bug was observed there. However, the PR which fixes this was merged to the main branch to be fixed in 3.0.0. Was it not possible to fix this in 2.1.1? Or are you intending to backport the fix to the 2.1 maintenance branch?

[DomGarguilo]

@DomGarguilo This ticket was marked to be fixed for 2.1.1, because the bug was observed there. However, the PR which fixes this was merged to the main branch to be fixed in 3.0.0. Was it not possible to fix this in 2.1.1? Or are you intending to backport the fix to the 2.1 maintenance branch?

I can backport it to 2.1 too. I'll work on another PR against the 2.1 branch.