問題描述

我試圖為由 2 個 mysql 主機組成的主機組使用 ansible 設置 mysql 主從復制.

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

這是我的場景:

我在第一個主機上運行一個任務并跳過第二個主機，所以第一個任務(即主復制狀態)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 個主機上運行另一個任務(跳過第一個主機)，該任務使用第一個任務的返回值，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.

現在，當我運行劇本時，第一個任務的變量似乎在第二個任務中不起作用

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

庫存文件

    [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 上的任務

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

- debug: var=master

Slave 上的任務

- 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

主輸出

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
    }
}

從輸出

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，由于未定義的變量，第二個主機的第二個任務失敗.但是，第一個主機的第一個任務中存在所需的變量.

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.

如何在另一個任務中使用從第一臺主機返回到第二臺主機的變量?

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

P.S:我見過使用 {{ hostvars['inventory_hostname']['variable'] }} 的方法.但是我對這種方法很困惑，因為需要直接添加庫存主機名或 IP 地址.我正在尋找可用于不同清單文件和劇本的通用模板.

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.

推薦答案

我解決了我的問題>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.

如何設置注冊變量以在 ansible 中的播放之間保持不變?但是直到我發布這個問題我才注意到它.

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.

這是我在 ansible 任務中所做的:

Here is what I did in the ansible tasks:

• 我創建了一個虛擬主機 master_value_holder 并定義了所需的變量.(這里我需要 master_log_file 和master_log_Postion)
• 使用 hostvars['master_value_holder']['master_log_file'] 訪問變量

• 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 上的任務

- 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 的任務

- 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

輸出

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]

從上面的輸出中可以看出，主復制狀態現在對兩臺主機都可用.

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

這篇關于如何在ansible中為不同的主機使用另一個任務中的一個任務的返回值的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！