Revisit conflicting package removal

In https://review.openstack.org/534819 we introduced the removal
of conflicting packages from the targeted host, but then we deleted
the list for RedHat in https://review.openstack.org/578844 because
yum kept removing and re-adding the same packages.

In https://review.openstack.org/603205 we solve the issue properly
given that yum is case-insensitive, and the root cause of the repeat
remove/install.

As such, in this patch, we restore the removal of conflicting
packages for RedHat in a different way. Each of the package removal
tasks are moved into the tasks specific to each package manager so
that each can be handled differently.

Change-Id: I70fbfa6eff8796713c6bec32319382273f8281f8
Related-Bug: #1762421
Related-Bug: #1742206
(cherry picked from commit 72f402d3e9)

tasks/galera_install.yml

@@ -33,11 +33,6 @@
   when:
     - ansible_architecture == 'ppc64le'
 
-- name: Remove conflicting distro packages
-  package:
-    name: "{{ galera_server_mariadb_distro_packages_remove | default([]) }}"
-    state: absent
-
 - include_tasks: "galera_install_{{ ansible_pkg_mgr }}.yml"
 
 - name: Record galera has been deployed

tasks/galera_install_apt.yml

@@ -13,6 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Remove conflicting distro packages
+  package:
+    name: "{{ galera_server_mariadb_distro_packages_remove | default([]) }}"
+    state: absent
+
 - name: If a keyfile is provided, copy the gpg keyfile to the key location
   copy:
     src: "{{ item.keyfile }}"

tasks/galera_install_yum.yml

@@ -13,6 +13,29 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Unfortunately yum is case-insensitive, and RDO has mariadb-* packages,
+# while the MariaDB repo has MariaDB-* packages and they conflict.
+# To work around this we have to query for any installed RDO/CentOS
+# packages using rpm, then remove them. We have to remove them without
+# dependencies, otherwise for distro package installation types on shared
+# hosts it removes far too many packages.
+- name: Remove conflicting packages
+  shell: |
+    exit_code=0
+    for pkg in {{ galera_server_mariadb_distro_packages_remove | join(' ') }}; do
+      if rpm --query --quiet ${pkg}; then
+        rpm -ev --nodeps ${pkg}
+        exit_code=2
+      fi
+    done
+    exit ${exit_code}
+  register: _remove_existing_mariadb_packages
+  changed_when: _remove_existing_mariadb_packages.rc == 2
+  failed_when: _remove_existing_mariadb_packages.rc not in [0, 2]
+  args:
+    warn: no
+    executable: /bin/bash
+
 - name: Update the local file system CRUD
   file:
     src: "{{ item.src|default(omit) }}"

tasks/galera_install_zypper.yml

@@ -13,6 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Remove conflicting distro packages
+  package:
+    name: "{{ galera_server_mariadb_distro_packages_remove }}"
+    state: absent
+
 - name: Update the local file system CRUD
   file:
     src: "{{ item.src|default(omit) }}"

vars/redhat-7.yml

@@ -54,6 +54,12 @@ galera_server_mariadb_distro_packages:
   - rsync
   - socat
 
+# Conflicting packages with those from the MariaDB repository
+galera_server_mariadb_distro_packages_remove:
+  - mariadb-common
+  - mariadb-config
+  - mariadb-server
+
 # The packages to uninstall during an upgrade from a previous version
 galera_server_upgrade_packages_remove:
   - MariaDB-Galera-server