将运行RHEL7和MySQL5.7的服务器升级到RHEL8.

备份重要数据和配置文件。

执行以下命令更新更新RHEL 7系统和所有软件包：

sudo yum update

禁用所有存在的第三方存储库。不禁用会导致系统更新不成功。

安装升级插件和EPEL存储库：

sudo yum install epel-release
sudo yum install python2-pip
sudo pip install --upgrade pip
sudo pip install 'ansible<=2.7'

创建一个用于升级的Ansible Playbook：

---
- name: Upgrade server from RHEL 7 to RHEL 8
  hosts: all
  become: true

  tasks:
  - name: Install the Pre-upgrade Assistant package
    package:
      name: redhat-upgrade-tool
      state: present

  - name: Run the Pre-upgrade Assistant
    command: preupg -s RHEL/7 -8
    register: preupg

  - name: Print Pre-upgrade Assistant results
    debug:
      var: preupg.stdout_lines

  - name: Upgrade distribution packages
    command: rpm -Va --nofiles --nodigest
    register: var1

  - name: Print updated distribution packages
    debug:
      var: var1.stdout_lines

  - name: Perform the actual upgrade
    command: /usr/bin/rhui-installer /usr/share/redhat-upgrade-tool/upgrade/minimal-rhui-image/rhui-minimal.img
    register: upgrade

  - name: Print upgrade results
    debug:
      var: upgrade.stdout_lines

  - name: Reboot the system
    reboot:
      reboot_timeout: 600
      pre_reboot_delay: 5
      post_reboot_delay: 5
      test_command: uptime

  - name: Check if the upgrade was successful
    assert:
      that: ansible_distribution_major_version == '8'

在此Playbook中，执行以下操作：

• 安装预升级助手包。
• 运行预升级助手。
• 更新发行版软件包。
• 执行实际升级。
• 重启系统。
• 检查升级是否成功。

运行升级Playbook：

ansible-playbook upgrade-rhel7-to-rhel8.yaml -i inv.txt