[ansible series] fundamentals -01

1. brief introduction

• Ansible Tracing to the source
  Ansible From science fiction , It is a fictitious communication device that transmits information at the speed of Superlight .
• Ansible What is it? ？
  Ansible It is a modular automatic operation and maintenance tool , be based on python Language implementation , from Paramiko,PyYAML and Jinjia2 It consists of three key modules .Ansible Supports multi node publishing 、 Remote task execution , By default SSH Make a remote connection .
• Ansible Basic framework
  
  Ansible The composition of the basic architecture ：
  Host Inventory： Host list , Definition ansible Managed hosts
  Playbooks： Script ,ansible Task configuration file for , Define multiple tasks in the script ,ansible Automatic execution
  Ansible： The core
  Core Module： Core module ,ansible Bring their own
  Custom Module： Extension module , If the core module is not enough to accomplish some function , You can add expansion modules
  Plugins： Complete the supplement of module function
  Connection Plugins：ansible By default ssh Connect to each host , But other connection methods are also supported

2.Ansible install

The main installation methods are as follows 4 Kind of

• Method 1：yum install

yum install epel-release
yum install ansible

• Method 2：pip install

pip install ansible

• Method 3：brew install

brew install ansible

• Method 4： Source code installation （mac recommend ）

git clone https://github.com/ansible/ansible.git
cd ansible
sudo python setup.py install 

After installation , Use ansible --version Check if the installation is successful
The installation succeeds when the version information is displayed , Here's the picture
Refer to the figure

3. To configure SSH secret key （ Secret free connection of controlled host ）

Test environment ： CentOS Linux release 7.7.1908 (Core)
The test is conducted locally , That is, both the control host and the controlled host are localhost

• Generate key file

ssh-keygen

ssh-keygen No parameters after , Default generation rsa Type key file , If the following box appears, the key generation is successful . Key file in /root/.ssh Under the table of contents .
Refer to the figure

• Password free login
  After generating the key file, enter , Following commands , You need to enter the password once during

ssh-copy-id localhost

Refer to the figure

It's going on ssh localhost when , You no longer need to enter a password , Direct access to

4. ansible The configuration file

• modify ansible.cfg The configuration file
  Ansible Profile location /etc/ansible/ansible.cfg
  Configuration file changes

  • Get rid of host_key_checking = False Before # Number , Disable every execution ansible Command check ssh key host
  • Get rid of log_path = /var/log/ansible.log Before # Number , Log on

5. test

5.1 The test sample 1

stay /etc/ansible/hosts end of file , add to localhost, Save file exit

Refer to the figure

Enter the following command to perform the connectivity test

ansible all -m ping

The test results are as follows ：

5.2 The test sample 2

This sample implements a ansible Version of Hello World!
Create a new directory , Create... In this directory inventory and all.yml Two documents

• inventory The contents of the document

[all]
localhost

Refer to the figure

• all.yml The contents of the document

---

- name: debug Hello World
  hosts: all
  gather_facts: no
  tasks:

  - name: debug
    debug:

Refer to the figure

• function

ansible-playbook -i inventory all.yml

The output results are shown in the figure below

msg Medium output Hello World!