Refactoring and Sharding a Monolithic State

Table of Contents

1. Challenge

   Analyze monolithic configurations to identify logical boundaries and inter-resource dependencies suitable for state sharding

   • List and count all resources in the monolithic state.
   • Categorize each resource into networking or compute layers.
   • Trace dependencies to confirm a one-way boundary from compute to networking.
2. Challenge

   Execute surgical resource migration between state files using CLI commands to achieve a sharded infrastructure architecture

   • Create the networking and compute shard configurations with matching resource addresses.
   • Move networking and compute resources into separate local state files using terraform state mv.
   • Push each shard to its own remote backend key and verify that the monolith state is empty.
3. Challenge

   Validate the integrity of the split states by performing plan operations and ensuring connectivity between partitioned components

   • Run terraform plan and terraform apply in each shard to confirm zero drift and save outputs.
   • Demonstrate reduced blast radius by applying a networking tag change and confirming that the compute shard remains unaffected.
   • Verify cross-shard connectivity through the remote state data source.
   • Compare resource counts across both shards with the original monolith and confirm that EC2 instances are running in the correct networking infrastructure.