Merge pull request #198 from percona/pxc-4610

PXC-4610 [DOCS]- update YUM limitation (8.4)

docs/yum.md

@@ -37,22 +37,20 @@ For information on SELinux, see [Enabling SELinux](selinux.md#selinux).
 
 For more information on the Percona Software repositories and configuring Percona Repositories with `percona-release`, see the [Percona Software Repositories Documentation](https://docs.percona.com/percona-software-repositories/index.html).
 
-=== "Install on Red Hat 7"
-
-    ```{.bash data-prompt="$"}
-    $ sudo yum install https://repo.percona.com/yum/percona-release-latest.noarch.rpm
-    $ sudo percona-release enable-only pxc-80 release
-    $ sudo percona-release enable tools release
-    $ sudo yum install percona-xtradb-cluster
-    ```
-
-=== "Install on Red Hat 8 or later"
-
-    ```{.bash data-prompt="$"}
-    $ sudo yum install https://repo.percona.com/yum/percona-release-latest.noarch.rpm
-    $ sudo percona-release setup pxc-80
-    $ sudo yum install percona-xtradb-cluster
-    ```
+
+## Install on Red Hat 8 or later
+
+RHEL 8 and other EL8 systems enable the MySQL module by default. This module hides the Percona-provided packages and the module must be disabled to make these packages visible. The following command disables the module: 
+
+```{.bash data-prompt="$"} 
+$ sudo yum module disable mysql
+```
+
+```{.bash data-prompt="$"}
+$ sudo yum install https://repo.percona.com/yum/percona-release-latest.noarch.rpm
+$ sudo percona-release setup pxc-84-lts
+$ sudo yum install percona-xtradb-cluster
+```
 
 ## After installation