| # Component manager |
| |
| <<../_v2_banner.md>> |
| |
| The component manager is the heart of the component framework. It maintains the |
| [component topology][doc-topology], manages |
| [component lifecycle][doc-lifecycle], provides components with the |
| [capabilities][doc-capabilities] they require at runtime, and keeps them |
| isolated from one another. |
| |
| ## Booting the system |
| |
| The component manager is responsible for starting most processes in the system. |
| It is one of the first processes created when the system boots and it is one |
| of the last processes destroyed when the system shuts down. |
| |
| The component manager coordinates the execution of all components, beginning |
| with the root component that is launched at boot. The root component then |
| asks the component manager to start other components such as the device |
| manager, filesystems, network stack, and other essential services. |
| |
| ## Intermediation |
| |
| The component manager intermediates all introductions between components at |
| runtime. |
| |
| For example, when a component connects to a [protocol][doc-protocol], the |
| component manager validates the request, uses |
| [capability routing][doc-capability-routing] to find the component that exposes |
| the desired service, starts it if needed, establishes a direct connection |
| between the client and the service, and continues to monitor the relationship so |
| that the client and service are held accountable for their behavior. |
| |
| The component manager has a highly privileged role in the system. Through |
| intermediation, it makes many critical decisions for system security and |
| stability. |
| |
| ## Framework capabilities |
| |
| The component manager offers a variety of framework capabilities to components. |
| Components use these capabilities to interact with their environment with the |
| help of the component manager. |
| |
| Commonly used framework capabilities include |
| [`fuchsia.sys2.Realm`](#realm-protocol) and [events](#events). |
| |
| ## Framework extensions |
| |
| The component manager supports a variety of framework extensions that |
| components can implement to integrate new functionality with their environment. |
| |
| - [Runners][doc-runners]: Integrate programming language runtimes and |
| application frameworks. |
| - [Resolvers][doc-resolvers]: Integrate software delivery systems. |
| |
| [doc-capabilities]: /docs/concepts/components/v2/capabilities |
| [doc-capability-routing]: /docs/concepts/components/v2/topology.md#capability-routing |
| [doc-hub]: /docs/concepts/components/v2/hub.md |
| [doc-lifecycle]: lifecycle.md |
| [doc-protocol]: /docs/concepts/components/v2/capabilities/protocol.md |
| [doc-realms]: /docs/concepts/components/v2/realms.md |
| [doc-resolvers]: /docs/concepts/components/v2/capabilities/resolvers.md |
| [doc-runners]: /docs/concepts/components/v2/capabilities/runners.md |
| [doc-topology]: /docs/concepts/components/v2/topology.md |
| [events]: /docs/concepts/components/v2/capabilities/event.md |
| [realm-protocol]: /sdk/fidl/fuchsia.sys2/realm.fidl |
