mysql - 如何在ansible中为不同主机使用另一个任务中一个任务的返回值

Question

我试图使用ansible为由2个mysql主机组成的主机组设置mysql主从复制。

这是我的场景:

我在第一台主机上运行一个任务并跳过第二台主机，因此第一个任务(即主复制状态)返回一些值，例如位置、文件等。

然后，我在第二个主机中运行另一个任务(跳过第一个主机)，该任务使用第一个任务的返回值，如 master.Position、master.File 等。

现在，当我运行剧本时，第一个任务的变量似乎在第二个任务中不起作用

库存文件

    [mysql]
    stagmysql01 ansible_host=1.1.1.1 ansible_ssh_user=ansible ansible_connection=ssh
    stagmysql02 ansible_host=1.1.1.2 ansible_ssh_user=ansible ansible_connection=ssh 

Master 的任务

- name: Mysql - Check master replication status.
  mysql_replication: mode=getmaster
  register: master

- debug: var=master

从属任务

- name: Mysql - Configure replication on the slave.
  mysql_replication:
    mode: changemaster
    master_host: "{{ replication_master }}"
    master_user: "{{ replication_user }}"
    master_password: "{{ replication_pass }}"
    master_log_file: "{{ master.File }}"
    master_log_pos: "{{ master.Position }}"
  ignore_errors: True

主输出

TASK [Mysql_Base : Mysql - Check master replication status.] ****************
skipping: [stagmysql02]
ok: [stagmysql01]

TASK [Mysql_Base : debug] ***************************************************
ok: [stagmysql01] => {
    "master": {
        "Binlog_Do_DB": "", 
        "Binlog_Ignore_DB": "mysql,performance_schema", 
        "Executed_Gtid_Set": "", 
        "File": "mysql-bin.000003", 
        "Is_Master": true, 
        "Position": 64687163, 
        "changed": false, 
        "failed": false
    }
}
ok: [stagmysql02] => {
    "master": {
        "changed": false, 
        "skip_reason": "Conditional result was False", 
        "skipped": true
    }
}

从输出

TASK [Mysql_Base : Mysql - Configure replication on the slave.] *************
skipping: [stagmysql01]
fatal: [stagmysql02]: FAILED! => {"failed": true, "msg": "The task includes an option with an undefined variable. The error was: 'dict object' has no attribute 'File'\n\nThe error appears to have been in '/root/ansible/roles/Mysql_Base/tasks/replication.yml': line 30, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- name: Mysql - Configure replication on the slave.\n  ^ here\n\nexception type: <class 'ansible.errors.AnsibleUndefinedVariable'>\nexception: 'dict object' has no attribute 'File'"}
...ignoring

正如您在上面看到的，由于 undefined variable ，第二个主机的第二个任务失败。但是，所需的变量存在于第一个主机的第一个任务中。

如何在另一个任务的第二台主机中使用从第一台主机返回的变量？

P.S:我已经看到了使用 {{ hostvars['inventory_hostname']['variable'] }} 的方法。然而，我对这种方法很困惑，因为需要直接添加 inventory_hostname 或 IP 地址。我一直在寻找一个可用于不同库存文件和剧本的通用模板。

Answer 1

通过将变量定义到新的虚拟主机，然后通过hostvars在剧本中使用它，我能够解决我的问题。

How do I set register a variable to persist between plays in ansible? 中的一个答案中已经提到了类似的解决方案然而，直到我发布这个问题我才注意到它。

这是我在 ansible 任务中所做的事情:

• 我创建了一个虚拟主机 master_value_holder 并定义了所需的变量。 (这里我需要master_log_file和master_log_Postion)
• 使用hostvars['master_value_holder']['master_log_file']访问变量

Master 的任务

- name: Mysql - Check master replication status.
  mysql_replication: mode=getmaster
  register: master

- name: "Add master return values to a dummy host"
  add_host:
    name:   "master_value_holder"
    master_log_file: "{{ master.File }}"
    master_log_pos: "{{ master.Position }}"

从站的任务

- name: Mysql - Displaying master replication status
  debug: msg="Master Bin Log File  is {{ hostvars['master_value_holder']['master_log_file'] }} and Master Bin Log Position is {{ hostvars['master_value_holder']['master_log_pos'] }}"

- name: Mysql - Configure replication on the slave.
  mysql_replication:
    mode: changemaster
    master_host: "{{ replication_master }}"
    master_user: "{{ replication_user }}"
    master_password: "{{ replication_pass }}"
    master_log_file: "{{ hostvars['master_value_holder']['master_log_file'] }}"
    master_log_pos: "{{ hostvars['master_value_holder']['master_log_pos'] }}"
  when: ansible_eth0.ipv4.address != replication_master and not slave.Slave_SQL_Running

输出

TASK [Mysql_Base : Mysql - Check master replication status.] ****************
skipping: [stagmysql02]
ok: [stagmysql01]

TASK [AZ-Mysql_Base : Add master return values to a dummy host] ****************
changed: [stagmysql01]

TASK [AZ-Mysql_Base : Mysql - Displaying master replication status] ************
ok: [stagmysql01] => {
    "msg": "Master Bin Log File  is mysql-bin.000001 and Master Bin Log Position is 154"
}
ok: [stagmysql02] => {
    "msg": "Master Bin Log File  is mysql-bin.000001 and Master Bin Log Position is 154"
}

TASK [AZ-Mysql_Base : Mysql - Configure replication on the slave.] *************
skipping: [stagmysql01]
skipping: [stagmysql02]

从上面的输出可以看出，现在两台主机都处于主复制状态。