如何让 Ansible 在已配置的主机上跳过运行任务? [英] How to let Ansible to skip run tasks on a host when its already configured?

问题描述

我们有 2 个剧本 Basic-env 和 Upgrade-env 来管理我们的主机.

We have 2 playbooks Basic-env and Upgrade-env to manager our hosts.

ansible-playbook Basic-env 正在做基本的环境设置(yum、生成密钥、安全任务)并注册服务.

The ansible-playbook Basic-env is doing the the basic environment setup(yum, generate keys, security tasks) and register the services.

ansible-playbook Upgrade-env 正在对软件和配置进行无中断升级 (NDU).

The ansible-playbook Upgrade-env is doing the non-disruptive Upgrade(NDU) for the software and configuration.

我们会动态地将新主机放入库存，并每 10 分钟运行一次 Basic-env.

We will dynamic put new hosts into inventory, and run Basic-env each 10 mins.

问题:是否可以让ansible跳过在旧主机上执行Basic-env中的任务而只在新主机上运行它们?

Question: Is possible to let ansible skip execute the tasks which in Basic-env at old hosts and only run them in new hosts?

注意:我们不想为每个新主机单独运行 playbook，而是为所有主机每 10 分钟运行一次 Basic-env.

Note: We do not want to run playbook for each new hosts separately, instead run run Basic-env each 10 mins for all hosts.

推荐答案

您可以简单地检查主机上的某些内容.假设您的剧本生成文件 /foo/bar.然后在你的剧本/角色的开头有一个这样的任务:

You could simply check for something on the host. Let's say your playbook generates the file /foo/bar. Then at the beginning of your playbook/role have a task like this:

- stat:
    path: /foo/bar
  register: check

然后对于您不想处理的任何任务，您可以应用这样的条件:

Then for any task which you do not want to process you can apply a condition like this:

when: not p.stat.exists

另一种(也许更简洁)的解决方案是使用本地事实.在你的剧本的最后创建一个文件 /etc/ansible/facts.d/setup_complete.fact ，内容如下:

Another (and maybe cleaner) solution is to use local facts. At the very end of your playbook create a file /etc/ansible/facts.d/setup_complete.fact with the content:

{"setup_complete": "true"}

当 Ansible 下次运行时，ansible_local.setup_complete 将可用.那么你的情况可能看起来像

When Ansible runs the next time, the fact ansible_local.setup_complete will be available. Then your condition could look like

when: "setup_complete" not in ansible_local

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