Argo CD components, CRDs and architectural patterns.
It runs the Argo CD API server which exposes the API consumed by the Web UI, CLI, and CI/CD systems.
- Application management and status reporting
- Invoking of application operations (e.g. sync, rollback, user-defined actions)
- Repository and cluster credential management (stored as Kubernetes secrets)
- Authentication and auth delegation to external identity providers
- RBAC enforcement
- Listener/forwarder for Git webhook events
It runs Argo CD Application Controller, which is a Kubernetes controller, that continuously monitors running applications and compares the current state against the desired target state.
- OutOfSync application state detection
- Optionally takes corrective actions against OutOfSync states
- Invoking any user-defined hooks for lifecycle events (e.g. PreSync, Sync, PostSync)
It runs Argo CD Repository Server, which maintains a local cache of the Git repository holding the application manifests.
- Generating and returning the Kubernetes manifests based on:
- Repository URL
- Revision (commit, tag, branch)
- Application path
- Template specific settings (e.g. parameters, Helm values.yaml)
It runs Argo CD Dex, which is an identity service that uses OpenID Connect to drive authentication for Argo CD.
- Deferring authentication to:
- LDAP servers
- SAML providers
- Other identity providers, such as GitHub, Google, and Active Directory
It runs Redis, which is an open source in-memory data structure store, used as a database.
Application is a custom Resource Definition (CRD) which represents a deployed application instance in an environment. It is defined by two key pieces of information:
- Source: reference to the desired state in Git (repository, revision, path, environment)
- Destination: reference to the target cluster and namespace
Projects provide a logical grouping of applications. It can apply restrictions to applications, such as:
- What may be deployed (trusted Git sources)
- Where apps may be deployed to (destination clusters and namespaces)
- What kinds of objects may be deployed (e.g. RBAC, CRDs, DaemonSets, NetworkPolicy)
- Defining project roles to provide application RBAC (bound to OIDC groups and/or JWT tokens)
App of Apps (Cluster Bootstrapping)
It is a pattern that creates an Argo CD application that creates other apps. This allows you to declaratively manage a group of apps that can be deployed and configured.