cert-manager/trust-manager

trust-manager is a Kubernetes operator that distributes trust bundles across a cluster.

The tool solves the problem of managing certificate trust sources consistently across Kubernetes environments. It accepts a list of trusted certificate sources, combines them into a unified bundle, and makes that bundle available to applications throughout the cluster. Supported sources include public trust bundles equivalent to those provided by operating systems. When a bundle configuration changes, the tool automatically updates the corresponding ConfigMap in all namespaces, eliminating manual synchronization.

The tool suits teams running Kubernetes or OpenShift clusters that need centralized certificate management. It is particularly useful when applications require consistent access to a standard set of trusted CAs without duplicating configuration across namespaces. The simplest use case involves deploying a bundle based on default CAs, which creates a ConfigMap in every namespace ready for applications to mount and use.

Development activity shows a structured approach to testing and maintenance. The project maintains three distinct test categories—unit, integration, and end-to-end smoke tests—all of which run against every pull request alongside other checks. The codebase uses makefile-modules for shared build infrastructure, with changes to shared files synchronized from an upstream repository. Local development is supported through make targets that provision a Kind cluster with Docker and install both trust-manager and its cert-manager dependency for testing purposes.