Expand on the definition of our ops

runtime.md

@@ -1,19 +1,15 @@
 # Runtime and Lifecycle
 
-## State
+## Scope of a Container
+
+Barring access control concerns, the entity using a runtime to create a container MUST be able to use the operations defined in this specification against that same container.
+Whether other entities using the same, or other, instance of the runtime can see that container is out of scope of this specification.
 
-Runtime MUST store container metadata on disk so that external tools can consume and act on this information.
-It is recommended that this data be stored in a temporary filesystem so that it can be removed on a system reboot.
-On Linux/Unix based systems the metadata MUST be stored under `/run/opencontainer/containers`.
-For non-Linux/Unix based systems the location of the root metadata directory is currently undefined.
-Within that directory there MUST be one directory for each container created, where the name of the directory MUST be the ID of the container.
-For example: for a Linux container with an ID of `173975398351`, there will be a corresponding directory: `/run/opencontainer/containers/173975398351`.
-Within each container's directory, there MUST be a JSON encoded file called `state.json` that contains the runtime state of the container.
-For example: `/run/opencontainer/containers/173975398351/state.json`.
+## State
 
-The `state.json` file MUST contain all of the following properties:
+The state of a container MUST include, at least, the following propeties:
 
-* **`version`**: (string) is the OCF specification version used when creating the container.
+* **`ociVersion`**: (string) is the OCI specification version used when creating the container.
 * **`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.
@@ -23,37 +19,111 @@ This allows the hooks to perform cleanup and teardown logic after the runtime de
 * **`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.
 
-*Example*
-
+When serialized in JSON, the format MUST adhere to the following pattern:
 ```json
 {
-    "version": "0.2.0",
-    "id": "oc-container",
+    "ociVersion": "0.2.0",
+    "id": "oci-container1",
     "pid": 4422,
     "bundlePath": "/containers/redis"
 }
 ```
 
+See [Query State](#query-state) for information on retrieving the state of a container.
+
 ## 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 by passing the bundle path as argument.
-2. The container's runtime environment is created according to the configuration in [`config.json`](config.md).
-   Any updates to `config.json` after container is running do not affect the container.
-3. The container's state.json file is written to the filesystem.
-4. The prestart hooks are invoked by the runtime.
-   If any prestart hook fails, then the container is stopped and the lifecycle continues at step 8.
-5. The user specified process is executed in the container.
-6. The poststart hooks are invoked by the runtime.
-   If any poststart hook fails, then the container is stopped and the lifecycle continues at step 8.
-7. Additional actions such as pausing the container, resuming the container or signaling the container may be performed using the runtime interface.
-   The container could also error out or crash.
-8. The container is destroyed by undoing the steps performed during create phase (step 2).
-9. The poststop hooks are invoked by the runtime and errors, if any, are logged.
-10. The state.json file associated with the container is removed and the return code of the container's user specified process is returned or logged.
+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.
+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 8.
+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 8.
+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, MAY 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.
 
+## Operations
+
+OCI compliant runtimes MUST support the following operations, unless the operation is not supported by the base operating system.
+
+### Errors
+In cases where the specified operation generates an error, this specification does not mandate how, or even if, that error is returned or exposed to the user of an implementation.
+Unless otherwise stated, generating an error MUST leave the state of the environment as if the operation were never attempted - modulo any possible trivial ancillary changes such as logging.
+
+### Query State
+
+`state <container-id>`
+
+This operation MUST generate an error if it is not provided the ID of a container.
+This operation MUST return the state of a container as specified in the [State](#state) section.
+In particular, the state MUST be serialized as JSON.
+
+
+### Start
+
+`start <container-id> <path-to-bundle>`
+
+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.
+
+Attempting to start an already running container MUST have no effect on the container and MUST generate an error.
+
+### Stop
+
+`stop <container-id>`
+
+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.
+
+### Exec
+
+`exec <container-id> <path-to-json>`
+
+This operation MUST generate an error if it is not provided the container ID and a path to the JSON describing the process to start.
+The JSON describing the new process MUST adhere to the [Process configuration](config.md#process-configuration) definition.
+This operation MUST create a new process within the scope of the container.
+If the container is not running then this operation MUST have no effect on the container and MUST generate an error.
+Executing this operation multiple times MUST result in a new process each time.
+Example:
+```
+{
+    "terminal": true,
+    "user": {
+        "uid": 0,
+        "gid": 0,
+        "additionalGids": null
+    },
+    "args": [
+        "/bin/sleep",
+        "60"
+    ],
+    "env": [
+        "version=1.0"
+    ],
+    "cwd": "...",
+}
+```
+This specification does not manadate the name of this JSON file.
+See the specification of the `config.json` file for the definition of these fields.
+The stopping, or exiting, of these secondary process MUST have no effect on the state of the container.
+In other words, a container (and its PID 1 process) MUST NOT be stopped due to the exiting of a secondary process.
+
 ## Hooks
 
-See [runtime configuration for hooks](./config.md#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.