lib: introduce global -w option for VRF netns backend

Current -n option is only for zebra and mgmtd. All other daemons receive
the VRF backend configuration from zebra upon connection to it. This
leads to a potential race condition - daemons need to know the backend
before they start reading their config, but they can be not connected to
zebra yet at this point. As the VRF backend cannot change during runtime,
let's introduce a new global -w option for setting netns backend, to
make sure that all daemons know their VRF backend immediately after
start.

The reason for introducing a new option instead of making -n global is
that ospfd already uses -n for another purposes.

Signed-off-by: Igor Ryzhov <idryzhov@gmail.com>

3 files changed, 15 insertions, 0 deletions

diff --git a/doc/manpages/frr-zebra.rst b/doc/manpages/frr-zebra.rst
index 6cc46b806d..356c128e30 100644
--- a/doc/manpages/frr-zebra.rst
+++ b/doc/manpages/frr-zebra.rst
@@ -38,6 +38,8 @@ OPTIONS available for the |DAEMON| command:
 
    Enable namespace VRF backend. By default, the VRF backend relies on VRF-lite support from the Linux kernel. This option permits discovering Linux named network namespaces and mapping it to FRR VRF contexts.
 
+   This option is deprecated. Please use the global -w option instead.
+
 ROUTES
 ------
 
diff --git a/doc/user/basic.rst b/doc/user/basic.rst
index 5fdd1887fa..b2d47a38eb 100644
--- a/doc/user/basic.rst
+++ b/doc/user/basic.rst
@@ -754,6 +754,17 @@ These options apply to all |PACKAGE_NAME| daemons.
    be added to all files that use the statedir.  If you have "/var/run/frr"
    as the default statedir then it will become "/var/run/frr/<namespace>".
 
+.. option:: -w, --vrfwnetns
+
+   Enable namespace VRF backend. By default, the VRF backend relies on VRF-lite
+   support from the Linux kernel. This option permits discovering Linux named
+   network namespaces and mapping them to FRR VRF contexts. This option must be
+   the same for all running daemons. The easiest way to pass the same option to
+   all daemons is to use the ``frr_global_options`` variable in the
+   :ref:`Daemons Configuration File <daemons-configuration-file>`.
+
+   .. seealso:: :ref:`zebra-vrf`
+
 .. option:: -o, --vrfdefaultname <name>
 
    Set the name used for the *Default VRF* in CLI commands and YANG models.
diff --git a/doc/user/zebra.rst b/doc/user/zebra.rst
index ac29b1c7d4..ef3a619853 100644
--- a/doc/user/zebra.rst
+++ b/doc/user/zebra.rst
@@ -53,6 +53,8 @@ Besides the common invocation options (:ref:`common-invocation-options`), the
    VRF defined by *Zebra*, as usual. If this option is specified when running
    *Zebra*, one must also specify the same option for *mgmtd*.
 
+   This options is deprecated. Please use the global -w option instead.
+
    .. seealso:: :ref:`zebra-vrf`
 
 .. option:: -z <path_to_socket>, --socket <path_to_socket>