Merge pull request #953 from kinvolk/alban/hook-paths

config: Clarify execution environment for hooks

Author: crosbymichael

config.md

@@ -375,6 +375,7 @@ For POSIX platforms, the configuration structure supports `hooks` for configurin
         Entries in the array contain the following properties:
         * **`path`** (string, REQUIRED) with similar semantics to [IEEE Std 1003.1-2008 `execv`'s *path*][ieee-1003.1-2008-functions-exec].
             This specification extends the IEEE standard in that **`path`** MUST be absolute.
+            Runtimes MUST resolve this value in the [runtime namespace](glossary.md#runtime-namespace).
         * **`args`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2008 `execv`'s *argv*][ieee-1003.1-2008-functions-exec].
         * **`env`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2008's `environ`][ieee-1003.1-2008-xbd-c8.1].
         * **`timeout`** (int, OPTIONAL) is the number of seconds before aborting the hook.
@@ -386,6 +387,7 @@ For POSIX platforms, the configuration structure supports `hooks` for configurin
 
 Hooks allow users to specify programs to run before or after various lifecycle events.
 Hooks MUST be called in the listed order.
+Hooks MUST be executed in the [runtime namespace](glossary.md#runtime-namespace).
 The [state](runtime.md#state) of the container MUST be passed to hooks over stdin so that they may do work appropriate to the current state of the container.
 
 ### <a name="configHooksPrestart" />Prestart