docs(genesis): explain shared image activation

docs/source/developers/guides/code/genesis_openembedded_plan.rst

@@ -230,8 +230,14 @@ xCAT server boundary
 --------------------
 
 The OpenEmbedded layer builds and exports a kernel, compressed initramfs,
-checksums, reports, and optional signed extensions.  Installing those
-artifacts and writing network boot configuration belongs to xCAT server code.
+checksums, reports, and optional signed extensions.  Packages install each
+export under ``genesis-openembedded/ARCH``.  ``mknb`` verifies and publishes
+that export when present, while retaining the old Genesis path as a fallback.
+
+The management-node and service-node packages recommend the ``x86_64`` and
+``ppc64le`` images.  These are weak dependencies so an older or partial mirror
+does not block an xCAT upgrade.  Other target images can be installed from the
+same common repository before running ``mknb ARCH``.
 
 Server integration should be reviewed separately from the image.  Independent
 bugs found while testing Genesis, such as TFTP path handling or Kea policy,

docs/source/guides/admin-guides/references/man8/mknb.8.rst

@@ -34,11 +34,24 @@ for the same architecture that the management node is.  So you normally do not n
 
 If you make custom changes to the network boot root image, you will need to run \ **mknb**\  again to regenerate the diskless image to include your changes.  If you have an xCAT Hierarchical Cluster with Service Nodes having local /tftpboot directories (site.sharedtftp=0), you will need to copy the generated root image to each Service Node.
 
-An exported Genesis image is identified by ``xcat-genesis.manifest``, which records its format version and architecture. The directory also contains ``kernel``, ``initramfs.cpio.gz``, and ``SHA256SUMS`` in ``/opt/xcat/share/xcat/netboot/genesis/ARCH``. \ **mknb**\  verifies the manifest and both boot files before publishing them under the configured TFTP root. An incomplete or invalid export leaves the current boot files unchanged. The legacy ``fs/`` layout remains supported and is packed locally.
+An OpenEmbedded Genesis package installs an exported image under
+``/opt/xcat/share/xcat/netboot/genesis-openembedded/ARCH``.  \ **mknb**\
+prefers that image when it is installed.  Otherwise it uses the old image under
+``/opt/xcat/share/xcat/netboot/genesis/ARCH``.
+
+An export is identified by ``xcat-genesis.manifest``, which records its format
+version and architecture.  The directory also contains ``kernel``,
+``initramfs.cpio.gz``, and ``SHA256SUMS``.  \ **mknb**\  verifies the manifest
+and both boot files before publishing them under the configured TFTP root.  An
+incomplete or invalid export leaves the current boot files unchanged.  The
+legacy ``fs/`` layout remains supported and is packed locally.
 
 When multiple IPv4 addresses are configured for the same network, \ **mknb**\  uses a locally assigned ``site.master`` for the xcatd endpoint, or the first address reported by the operating system when ``site.master`` is not local. POWER discovery configurations also use this address for their kernel and initrd URLs.
 
-Presently, the architectures x86_64 and ppc64 are supported. For ppc64le, use the ppc64 architecture.
+OpenEmbedded images use the exact architecture names ``x86``, ``x86_64``,
+``ppc64``, ``ppc64le``, ``armv7hf``, ``aarch64``, and ``riscv64``.  If an
+OpenEmbedded ``ppc64le`` image is not installed, \ **mknb**\  keeps the old
+behavior and uses the legacy ``ppc64`` image.
 
 
 *******

docs/source/guides/install-guides/common_sections.rst

@@ -143,6 +143,12 @@ Unless you are downloading ``xcat-dep`` to match a specific version of xCAT, it'
         cd <os>/<arch>
         ./mklocalrepo.sh
 
+#. Configure the common repository from the same mirror.  This repository is
+   independent of the management-node operating system and architecture: ::
+
+        cd ~/xcat/xcat-dep/common
+        ./mklocalrepo.sh
+
 .. END_configure_xcat_local_repo_xcat-dep_RPM
 
 .. BEGIN_configure_xcat_local_repo_xcat-dep_DEBIAN
@@ -225,4 +231,3 @@ xCAT is started automatically after the installation, but the following commands
 
 
 .. END_verifying_xcat
-

docs/source/guides/install-guides/yum/configure_xcat.rst

@@ -6,14 +6,16 @@ xCAT software and repo files can be obtained from: `<http://xcat.org/download.ht
 Internet Repository
 -------------------
 
-Install ``xCAT-release`` to configure both the ``xcat-core`` and ``xcat-dep``
-repositories and their signing key::
+Install ``xCAT-release`` to configure the core, distribution-specific
+dependency, and common dependency repositories and their signing key::
 
     dnf install https://xcat.org/files/xcat/repos/yum/latest/xcat-core/xCAT-release-latest.noarch.rpm
 
-The dependency repository is selected automatically from the operating-system
-release and architecture reported by DNF.  The installed repository files are
-marked as configuration files, so package upgrades preserve local changes.
+The distribution-specific repository follows the operating-system release and
+architecture reported by DNF.  The common repository carries packages that do
+not depend on the management-node distribution, including OpenEmbedded Genesis
+images.  The installed repository files are marked as configuration files, so
+package upgrades preserve local changes.
 
 Continue to the next section to install xCAT.