Default to Rocky Linux instead of CentOS Stream

We agreed that CentOS Stream 9 images are not published as we keep it
for CI use only (to check potential failures before it hits RHEL).

We recommend Rocky Linux 9 instead.

Change-Id: I06e6746e5c2abbdcd97912ea2f99d82fc662531d

ansible/group_vars/all.yml

@@ -43,7 +43,7 @@ kolla_ansible_setup_gather_subset: "{{ omit }}"
 config_strategy: "COPY_ALWAYS"
 
 # Valid options are ['centos', 'debian', 'rocky', 'ubuntu']
-kolla_base_distro: "centos"
+kolla_base_distro: "rocky"
 
 kolla_internal_vip_address: "{{ kolla_internal_address | default('') }}"
 kolla_internal_fqdn: "{{ kolla_internal_vip_address }}"

doc/source/user/support-matrix.rst

@@ -24,7 +24,8 @@ Kolla Ansible supports the following host Operating Systems (OS):
 .. note::
 
    CentOS Stream 9 is supported as a host OS while Kolla does not publish CS9
-   based images. Users can build them on their own.
+   based images. Users can build them on their own. We recommend using Rocky
+   Linux 9 images instead.
 
 
 

etc/kolla/globals.yml

@@ -31,7 +31,7 @@ workaround_ansible_issue_8743: yes
 #config_strategy: "COPY_ALWAYS"
 
 # Valid options are ['centos', 'debian', 'rocky', 'ubuntu']
-#kolla_base_distro: "centos"
+#kolla_base_distro: "rocky"
 
 # Do not override this unless you know what you are doing.
 #openstack_release: "master"

releasenotes/notes/rocky-is-now-default-fa143fd417dd7132.yaml

@@ -0,0 +1,5 @@
+---
+other:
+  - |
+    Rocky Linux 9 based images are now recommended (instead of CentOS Stream
+    ones).