runtime: fail when a poststop hook fails

If a poststop hook run failed(maybe because the resource is still not ready to be recycled),
we expect that the delete operation could fail and be retried util all
poststop hooks run succeed.

Signed-off-by: Abel Feng <[email protected]>

config.md

@@ -634,7 +634,8 @@ The `poststart` hooks MUST be executed in the [runtime namespace](glossary.md#ru
 
 ### <a name="configHooksPoststop" />Poststop
 
-The `poststop` hooks MUST be called [after the container is deleted](runtime.md#lifecycle) but before the [`delete`](runtime.md#delete) operation returns.
+The `poststop` hooks MUST be called [after the user-specified process is killed](runtime.md#lifecycle), but before the [`delete`](runtime.md#delete) operation return.
+Runtime should make sure that if a `poststop` hook failed, the [`delete`](runtime.md#delete) operation could fail and be retried.
 Cleanup or debugging functions are examples of such a hook.
 
 The `poststop` hooks' path MUST resolve in the [runtime namespace](glossary.md#runtime-namespace).

runtime.md

@@ -76,7 +76,7 @@ The lifecycle describes the timeline of events that happen from when a container
 11. Runtime's [`delete`](runtime.md#delete) command is invoked with the unique identifier of the container.
 12. The container MUST be destroyed by undoing the steps performed during create phase (step 2).
 13. The [`poststop` hooks](config.md#poststop) MUST be invoked by the runtime.
-    If any `poststop` hook fails, the runtime MUST [log a warning](#warnings), but the remaining hooks and lifecycle continue as if the hook had succeeded.
+    If any `poststop` hook fails,  the runtime MUST [generate an error](#errors), so that the Runtime's [`delete`](runtime.md#delete) command fails and retry is required until all `poststop` hooks succeed.
 
 ## <a name="runtimeErrors" />Errors