doc/mgr: explain error message - dashboard.rst

Explain that an error message received in response to
"redirect_resolve_ip_addr True" might be caused by having an
insufficiently recent release of Ceph running in your cluster.

Fixes: https://tracker.ceph.com/issues/61312
Signed-off-by: Zac Dover <zac.dover@proton.me>
(cherry picked from commit 78545030761330c44168dbb3f8d1e4c3c9a9a3bd)

diff --git a/doc/mgr/dashboard.rst b/doc/mgr/dashboard.rst
index 696676aeb342c0d1ea3616d8c0fe23c3ceaa5e35..3080533e2166e376b34ea1f6797d66cd2d24bafe 100644 (file)
--- a/doc/mgr/dashboard.rst
+++ b/doc/mgr/dashboard.rst
@@ -1257,6 +1257,14 @@ You can disable it again by::
 
   $ ceph config set mgr mgr/dashboard/redirect_resolve_ip_addr False
 
+.. warning::
+
+   If you attempt to activate redirection by using the command above and you
+   get the error message ``EINVAL: unrecognized config option
+   'mgr/dashboard/redirect_resolve_ip_addr'``, then you might be running a
+   release of Ceph prior to version 17.2.6. This feature was introduced in
+   17.2.6, in this commit: https://github.com/ceph/ceph/pull/48219.
+
 HAProxy example configuration
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^