CALMS is a conceptual framework for the integration of development and operations (DevOps) teams, functions and systems within an organization. The CALMS framework is often used as a maturity model, helping managers to evaluate whether or not their organization is ready for DevOps -- and if not, what needs to change. The acronym CALMS is credited to Jez Humble, co-author of "The DevOps Handbook."
The five pillars of the CALMS framework for DevOps are:
Culture - there is a culture of shared responsibility.
Automation - team members seek out ways to automate as many tasks as possible and are comfortable with the idea of continuous delivery.
Lean - team members are able to visualize work in progress (WIP), limit batch sizes and manage queue lengths.
Measurement - data is collected on everything and there are mechanisms in place that provide visibility into all systems.
Sharing - there are user-friendly communication channels that encourage ongoing communication between development and operations.
The CALMS framework is sometimes considered an alternative to ITSM (Information Technology Service Management), a strategic approach to designing, delivering, managing and improving the way IT is used within an organization. ITSM, which is often associated with ITIL (Information Technology Infrastructure Library) is considered by some IT administrators to be too rigid and therefore incompatible with DevOps. CALMS is sometimes thought of as a way of negotiating the differences between the two approaches.