Sentinel
ELI5 — The Vibe Check
Sentinel is HashiCorp's policy engine for their tools — Terraform, Vault, Consul, Nomad. Before Terraform applies changes, Sentinel checks if they comply with your rules. 'Is the instance type approved?' 'Is encryption enabled?' If not, the apply is blocked. It's like a bouncer specifically for HashiCorp's ecosystem.
Real Talk
HashiCorp Sentinel is an embedded policy-as-code framework for the HashiCorp enterprise stack. It enforces policies during Terraform runs, Vault operations, and Consul/Nomad actions. Policies are written in the Sentinel language and evaluated at different enforcement levels (advisory, soft-mandatory, hard-mandatory). It's a paid feature of HashiCorp's enterprise products.
When You'll Hear This
"Sentinel blocks any Terraform plan that creates unencrypted storage." / "We have hard-mandatory Sentinel policies for production infrastructure changes."
Related Terms
Compliance
Compliance means following the rules — legal, industry, or governmental standards that say how you must handle data and security.
OPA (Open Policy Agent)
OPA is an open-source policy engine that lets you write rules in a language called Rego. 'Can this user access this resource?
Policy as Code
Policy as Code means writing your rules and compliance requirements as actual code that gets enforced automatically.
Terraform
Terraform is a tool that lets you describe your entire cloud infrastructure in code files, then type one command to make it real.