Add VFS context override for Accumulo DS

Add VFS context override for Accumulo DS

See this page at the bottom: https://geomesa.atlassian.net/wiki/spaces/GEOMESA/pages/502661122/GeoMesa+Accumulo+Distributed+Runtime+Tips

Basically we want to add a VFS context override to a DS and set it on the batch scanners so that we can test upgrades of geomesa iterators without switching the namespace context...allows for blue/green deploys

Original JIRA Issue: https://geomesa.atlassian.net/browse/GEOMESA-2431

Key: GEOMESA-2431
Type: Story
Priority: Major
Status: To Do
Resolution: Unresolved
Reporter: Andrew Hulbert
Created: Wed, 10 Oct 2018 14:38:24 -0400
Updated: Fri, 17 Apr 2020 13:38:18 -0400

Comments:

557058:48912df4-0004-4f90-9915-db26684ec006 (Tue, 14 Apr 2020 15:43:31 -0400):

Andrew Hulbert Emilio Lahr-Vivaz should we try and squeeze this in so that we can test GeoMesa 3.0 upgrades more easily? Or is it too late?

557058:da7f6dfa-f0a1-468b-aec5-2cb61273feb5 (Tue, 14 Apr 2020 16:07:22 -0400):

I feel like configuration is complicated enough that we shouldn't make it more complicated....
you can always clone a table to a new namespace (cloning doesn't copy the data).

557058:3bdf14b8-308b-42a1-93b4-2ee86eacfbc7 (Fri, 17 Apr 2020 13:18:56 -0400):

If you clone a table that is doing ingest it will then start copying though right? Or rather keep the old ones around.

557058:da7f6dfa-f0a1-468b-aec5-2cb61273feb5 (Fri, 17 Apr 2020 13:38:18 -0400):

true.

Start with the Accumulo data-store implementation and the batch scanner setup; the issue points to the GeoMesa Accumulo Distributed Runtime Tips page for the VFS context behavior. Done means the data store can override its VFS context for batch scanners, supporting iterator upgrades without switching the namespace context.