The follow index api completely reuses CCS infrastructure that was exposed via:
https://github.com/elastic/elasticsearch/pull/29495
This means that the leader index parameter support the same ccs index
to indicate that an index resides in a different cluster.
I also added a qa module that smoke tests the cross cluster nature of ccr.
The idea is that this test just verifies that ccr can read data from a
remote leader index and that is it, no crazy randomization or indirectly
testing other features.
This commit enables the run task for ccr by specifying that the ccr
project not be evaluated until after core is evaluated. This is
important since ccr is alphabetically before core and thus Gradle
evaluates it first.
Relates #3665
Martijn van Groningen
Jason Tedor