2 files changed, 6 insertions, 18 deletions
diff --git a/doc/source/admin/image-building.rst b/doc/source/admin/image-building.rst
index ead62e9af..6d585ba03 100644
--- a/doc/source/admin/image-building.rst
+++ b/doc/source/admin/image-building.rst
@@ -78,21 +78,6 @@ See the :ref:`support matrix <support-matrix-base-images>` for information on
 supported base image distribution versions and supported images on each
 distribution.
 
-The Train ``9.1.0`` release supports both CentOS 7 and 8 base container images.
-The default is to use CentOS 7. CentOS 8 may be used as follows:
-
-.. code-block:: console
-
-   kolla-build --base centos --base-tag 8
-
-Kolla uses the tag to set defaults for the distribution Python version and
-package manager. If you need to use a base image with a different tag, use the
-following options:
-
-.. code-block:: console
-
-   kolla-build --base centos --base-image <base image> --base-tag <base tag> --distro-package-manager dnf --distro-python-version 3.6
-
 It is possible to build only a subset of images by specifying them on the
 command line:
 
diff --git a/doc/source/support_matrix.rst b/doc/source/support_matrix.rst
index 4aa9e8df1..a44608340 100644
--- a/doc/source/support_matrix.rst
+++ b/doc/source/support_matrix.rst
@@ -17,14 +17,17 @@ The following base container images are supported:
 .. note::
 
    Train is the last release of Kolla to support CentOS 7 as a base container
-   image. The Train ``9.1.0`` release also supports CentOS 8 images, and
-   provides a route for migration.
+   image.
+
+.. note::
+
+   CentOS 8 is no longer supported since it has been marked as End of Life
+   and repositories have been removed from CentOS mirrors.
 
 ============= ============ ================
 Distribution  Default base Default base tag
 ============= ============ ================
 CentOS 7      centos       7
-CentOS 8      centos       8
 Debian Buster debian       10
 RHEL 8        rhel         8
 Ubuntu Bionic ubuntu       18.04