Code review comment for lp://staging/~foli/landscape-charm/tools-fixes

While the exclude tables argument is good for quick dev and migration checking, I'm sort of averse to adding a generic exclude tables argument.

All of these exclude tables arguments in this tool in general feel like a bandaid for something that landscape broke by not properly dropping a table that we no longer use when we removed it from our model. Hard-coding these known shortcomings in the code is the lesser evil than adding the flexibility to specify any exclude-tables on the commandline because it raises our awareness of patches that landscape now needs to clean up these orphaned tables.

If we further extend the db-migrator tool to allow users to override the intended behavior, we risk losing the data (the feedback loop from the pain of changing the tool) which was needed to just get the migration to work in the first place.

to be noted, the issues you have run into currently with ec2_region and change_package_lock_request and metadata_*_seq have each resulted in landscape db patches in trunk for our next release (so this won't hit other customers at some point).