Code duplication between bottlerocket and bottlerocket-core-kit repositiories

[rajivr]

Currently there seems to be code duplication between rust crates that are present in

• bottlerocket/sources
• bottlerocket-core-kit/sources

Is there any specific reason why this duplication exists? If so, which repository should we consider to be authoritative version of the code.

[cbgbt]

Hello,

I believe the entirety of this duplication is caused by the migration system used during Bottlerocket's in-place update process.

To make a long story short, the authoritative code is in bottlerocket-core-kit, and you can likely disregard the duplicated bottlerocket sources if you are not using the in-place update system.

To elaborate a bit:

Migrations run arbitrary signed binaries which are useful for making changes during the update process that can't be fixed by simply replacing the root partition. Most often they are used to update users' settings values when we make changes to the shape of settings objects, or modify default values.

In these cases, migrations inspect the running host's settings within the datastore to make the requisite modifications. This requires the datastore library, and historically the schnauzer templating engine to more deeply inspect settings that are dynamically generated during Bottlerocket's boot process.

In core-kit 6.0.0, we added several features to Bottlerocket's default settings system that should eliminate the need for schnauzer in migrations. I opened #4458 to track the removal of the duplicated sources that are no longer need as a result of that effort.

[rajivr]

Thanks @cbgbt for the reply.