Resources like security groups often require multiple ingress or egress blocks. Writing these manually creates maintenance debt. A single security policy change can require editing multiple identical blocks, increasing the chance of human error.
Dynamic blocks shift the work from writing repeated configuration to defining structured data. Terraform iterates over a collection and generates the nested blocks automatically during configuration evaluation. Once expanded, the provider receives the same API payload it would receive from manually written blocks.
The result is infrastructure defined by data structures rather than duplicated syntax.
This lesson explains how Terraform expands dynamic blocks, how iterator objects work, and why dynamic blocks cannot create structures outside the provider schema.