diff --git a/runtime.md b/runtime.md index 098851e22..c51949fa3 100644 --- a/runtime.md +++ b/runtime.md @@ -13,8 +13,6 @@ The state of a container MUST include, at least, the following properties: * **`id`**: (string) is the container's ID. This MUST be unique across all containers on this host. There is no requirement that it be unique across hosts. -The ID is provided in the state because hooks will be executed with the state as the payload. -This allows the hooks to perform cleanup and teardown logic after the runtime destroys its own state. * **`pid`**: (int) is the ID of the main process within the container, as seen by the host. * **`bundlePath`**: (string) is the absolute path to the container's bundle directory. This is provided so that consumers can find the container's configuration and root filesystem on the host. @@ -34,22 +32,19 @@ See [Query State](#query-state) for information on retrieving the state of a con ## Lifecycle The lifecycle describes the timeline of events that happen from when a container is created to when it ceases to exist. - -1. OCI compliant runtime is invoked with a reference to the location of the bundle. - How this reference is passed to the runtime is an implementation detail. +1. OCI compliant runtime's `create` command is invoked with a reference to the location of the bundle and a unique identifier. + How these references are passed to the runtime is an implementation detail. 2. The container's runtime environment MUST be created according to the configuration in [`config.json`](config.md). - Any updates to `config.json` after container is running MUST not affect the container. -3. The prestart hooks MUST be invoked by the runtime. - If any prestart hook fails, then the container MUST be stopped and the lifecycle continues at step 7. -4. The user specified process MUST be executed in the container. -5. The poststart hooks MUST be invoked by the runtime. - If any poststart hook fails, then the container MUST be stopped and the lifecycle continues at step 7. -6. Additional actions such as pausing the container, resuming the container or signaling the container MAY be performed using the runtime interface. - The container MAY also error out, exit or crash. -7. The container MUST be destroyed by undoing the steps performed during create phase (step 2). -8. The poststop hooks MUST be invoked by the runtime and errors, if any, SHOULD be logged. - -Note: The lifecycle is a WIP and it will evolve as we have more use cases and more information on the viability of a separate create phase. + While the resources requested in the [`config.json`](config.md) MUST be created, the user-specified code (from [`process`](config.md#process-configuration) MUST NOT be run at this time. + Any updates to `config.json` after this step MUST NOT affect the container. +3. Once the container is created additional actions MAY be performed based on the features the runtime chooses to support. + However, some actions might only be available based on the current state of the container (e.g. only available while it is started). +4. Runtime's `start` command is invoked with the unique identifier of the container. + The runtime MUST run the user-specified code, as specified by [`process`](config.md#process-configuration). +5. The container's process is stopped. + This MAY happen due to them erroring out, exiting, crashing or the runtime's `kill` operation being invoked. +6. Runtime's `delete` command is invoked with the unique identifier of the container. + The container MUST be destroyed by undoing the steps performed during create phase (step 2). ## Errors @@ -67,36 +62,50 @@ Note: these operations are not specifying any command-line APIs, and the paramen `state ` This operation MUST generate an error if it is not provided the ID of a container. +Attempting to query a container that does not exist MUST generate an error. This operation MUST return the state of a container as specified in the [State](#state) section. -### Start +### Create -`start ` +`create ` This operation MUST generate an error if it is not provided a path to the bundle and the container ID to associate with the container. -If the ID provided is not unique across all containers within the scope of the runtime, or is not valid in any other way, the implementation MUST generate an error. -Using the data in `config.json`, that are in the bundle's directory, this operation MUST create a new container. -This includes creating the relevant namespaces, resource limits, etc and configuring the appropriate capabilities for the container. -A new process within the scope of the container MUST be created as specified by the `config.json` file otherwise an error MUST be generated. +If the ID provided is not unique across all containers within the scope of the runtime, or is not valid in any other way, the implementation MUST generate an error and a new container MUST not be created. +Using the data in [`config.json`](config.md), this operation MUST create a new container. +This means that all of the resources associated with the container MUST be created, however, the user-specified process MUST NOT be run at this time. The runtime MAY validate `config.json` against this spec, either generically or with respect to the local system capabilities, before creating the container ([step 2](#lifecycle)). -If the runtime does not perform initial validation and triggers an error due to an invalid or incompatible configuration, it MUST generate an error and jump to cleanup ([step 7](#lifecycle)). -Runtime callers who are interested in pre-start validation can run [bundle-validation tools](implementations.md#testing--tools) before invoking the start operation. +Runtime callers who are interested in pre-create validation can run [bundle-validation tools](implementations.md#testing--tools) before invoking the create operation. + +Any changes made to the [`config.json`](config.md) file after this operation will not have an effect on the container. + +### Start +`start ` -Attempting to start an already running container MUST have no effect on the container and MUST generate an error. +This operation MUST generate an error if it is not provided the container ID. +Attempting to start a container that does not exist MUST generate an error. +Attempting to start an already started container MUST have no effect on the container and MUST generate an error. +This operation MUST run the user-specified code as specified by [`process`](config.md#process-configuration). +If the runtime fails to run the code as specified, an error MUST be generated. + +### Kill +`kill ` -### Stop +This operation MUST generate an error if it is not provided the container ID. +Attempting to send a signal to a container that is not running MUST have no effect on the container and MUST generate an error. +This operation MUST send the specified signal to the process in the container. -`stop ` +### Delete +`delete ` This operation MUST generate an error if it is not provided the container ID. -This operation MUST stop and delete a running container. -Stopping a container MUST stop all of the processes running within the scope of the container. -Deleting a container MUST delete the associated namespaces and resources associated with the container. -Once a container is deleted, its `id` MAY be used by subsequent containers. -Attempting to stop a container that is not running MUST have no effect on the container and MUST generate an error. +Attempting to delete a container that does not exist MUST generate an error. +Attempting to delete a container whose process is still running MUST generate an error. +Deleting a container MUST delete the resources that were created during the `create` step. +Note that resources associated with the container, but not created by this container, MUST NOT be deleted. +Once a container is deleted its ID MAY be used by a subsequent container. -## Hooks +## Hooks Many of the operations specified in this specification have "hooks" that allow for additional actions to be taken before or after each operation. See [runtime configuration for hooks](./config.md#hooks) for more information.