問題描述

我試圖為由 2 個(gè) mysql 主機(jī)組成的主機(jī)組使用 ansible 設(shè)置 mysql 主從復(fù)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(gè)主機(jī)上運(yùn)行一個(gè)任務(wù)并跳過第二個(gè)主機(jī)，所以第一個(gè)任務(wù)(即主復(fù)制狀態(tài))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(gè)主機(jī)上運(yùn)行另一個(gè)任務(wù)(跳過第一個(gè)主機(jī))，該任務(wù)使用第一個(gè)任務(wù)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(xiàn)在，當(dāng)我運(yùn)行劇本時(shí)，第一個(gè)任務(wù)的變量似乎在第二個(gè)任務(wù)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(wù)

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

- debug: var=master

Slave 上的任務(wù)

- 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(gè)主機(jī)的第二個(gè)任務(wù)失敗.但是，第一個(gè)主機(jī)的第一個(gè)任務(wù)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(gè)任務(wù)中使用從第一臺(tái)主機(jī)返回到第二臺(tái)主機(jī)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(duì)這種方法很困惑，因?yàn)樾枰苯犹砑訋齑嬷鳈C(jī)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(shè)置注冊(cè)變量以在 ansible 中的播放之間保持不變?但是直到我發(fā)布這個(gè)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(wù)中所做的:

Here is what I did in the ansible tasks:

• 我創(chuàng)建了一個(gè)虛擬主機(jī) 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(wù)

- 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(wù)

- 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(fù)制狀態(tài)現(xiàn)在對(duì)兩臺(tái)主機(jī)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(guān)于如何在ansible中為不同的主機(jī)使用另一個(gè)任務(wù)中的一個(gè)任務(wù)的返回值的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！