如何在ansible中为不同的主机使用另一个任务中的一个任务的返回值 [英] How to use return values of one task in another task for a different host in ansible

问题描述

我试图为由 2 个 mysql 主机组成的主机组使用 ansible 设置 mysql 主从复制.

I was trying to setup mysql master slave replication with ansible for a hostgroup consisting of 2 mysql hosts.

这是我的场景:

我在第一个主机上运行一个任务并跳过第二个主机，所以第一个任务(即主复制状态)返回一些值，如位置、文件等.

I run one task in the 1st host and skips the 2nd host, so the 1st task (i.e master replication status) returns some values like Position, File etc.

然后，我在第 2 个主机上运行另一个任务(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.

Then, I run another task in 2nd host (skips the 1st hosts), This task uses the return values of the 1st task like master.Position, master.File etc.

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

Now, when I run the playbook, the variables of the 1st task does not seem to be working in the 2nd task

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 上的任务

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

- debug: var=master

Slave 上的任务

- 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，由于未定义的变量，第二个主机的第二个任务失败.但是，第一个主机的第一个任务中存在所需的变量.

As, you can see above, the 2nd task failed for 2nd host because of undefined variables. However the required variables are there in 1st task of 1st host.

如何在另一个任务中使用从第一台主机返回到第二台主机的变量?

How do I use the variables returned from 1st host in 2nd host in another task ?

P.S:我见过使用 {{ hostvars['inventory_hostname']['variable'] }} 的方法.但是我对这种方法很困惑，因为需要直接添加库存主机名或 IP 地址.我正在寻找可用于不同清单文件和剧本的通用模板.

P.S: I have seen the approach of using {{ hostvars['inventory_hostname']['variable'] }}. However I'm quite confused with this approach as the inventory_hostname or IP address needs to be added directly. I was looking for a common template that can be used for different inventory files and playbooks.

推荐答案

我解决了我的问题>hostvars.

I was able to solve my problem by defining the variables to a new dummy host and then using it across the playbook with hostvars.

如何设置注册变量以在 ansible 中的播放之间保持不变?但是直到我发布这个问题我才注意到它.

Similar solution was already mentioned in one of the answers in How do I set register a variable to persist between plays in ansible? However I did not notice it until I posted this question.

这是我在 ansible 任务中所做的:

Here is what I did in the ansible tasks:

• 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

• I have created a dummy host master_value_holder and defined the required variables. (Here I needed master_log_file and master_log_Postion)
• Accessed the variables using hostvars['master_value_holder']['master_log_file']

Master 上的任务

- 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 }}"

Slave 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]

从上面的输出中可以看出，主复制状态现在对两台主机都可用.

As you can see from the above output that the master replication status is available for both the hosts now.

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