I will try to learn some more about packaging and play some with this . Meanwhile, for those interested - here are the some starter points around packaging stuff for bigtop.
0) top level build.gradle file defines all bigtop tasks. it sources a packages.gradle file that has the packaging tasks.
1) The bigtop.mk file defines all components in bigtop. it is referenced by packages.gradle.
2) Each component has a do-component-build script. That script builds the java project for you.
3) For deb and rpm specifics, those builders are in respective bigtop-packages/ directories. They
each use do-component-build to get the core jars. So the first step is to write do-component-build for tachyon, i think.
4) For smoke tests, you can just dump a groovy script into bigtop-tests/smoke-tests/tachyon.
For a simple example of how to package a single jar app, like mahout, you can see the
blog post : https://blogs.apache.org/bigtop/entry/getting_involved_with_bigtop_packaging .