1. Ansible architecture

Ansible's help documentation:
http://www.ansible.com.cn/index.html

2. Introduction to YAML Language

• Basic Rules

All members of the list (list, [,,,...]) begin with the same indentation level and begin with "-". Requirements - A space must be followed.

- apple
- banana
- orange
- pear

Corresponding python output

['apple', 'banana', 'orange', 'pear']

A dictionary (dictionary, {key1:value1, key2:value2, key3:value3,...}) consists of a set of keys: values, and a space must be followed.

node_a:
    conntimeout: 300
    external: 
    iface: eth0
    port: 556
    internal: 
    iface: eth0
    port: 778
    broadcast: 
    client: 1000
    server: 2000
node_b:
    0: 
    ip: 10.0.0.1
    name: b1
    1:
    ip: 10.0.0.2
    name: b2

Corresponding python output

{
    'node_b': {                       #Note the nesting hierarchy.
        0: None,                      #Notice the null value.
        'ip': '10.0.0.2',             #Note that key cannot be repeated, and repetition covers.
        'name': 'b2', 
        1: None
    }, 
    'node_a': {
        'iface': 'eth0', 
        'port': 778, 
        'server': 2000, 
        'broadcast': None,
        'client': 1000, 
        'external': None, 
        'conntimeout': 300, 
        'internal': None
    }
}

It is suggested that the yaml file should be the first line.

• Illustrative examples
  test.yaml

---
name: Tom Smith
age: 37
spouse: 
    name: Jane Smith
    age: 35
children: 
    - name1: Jimmy Smith
      age1: 15
    - name2: Jenny Smith
      age2: 12

• Read code for python

#!/usr/bin/python

import yaml

file = open("test.yaml")
x = yaml.load(file)
print x

results of enforcement

{
    'age': 37,
    'spouse': {
        'age': 25,
        'name': 'Jane Smith'
    }, 
    'name': 'Tom Smith', 
    'children': [
        {
            'age1': 15, 
            'name1':  'Jimmy Smith'
        }, 
        {
            'age2': 12, 
            'name2': 'Jenny Smith'
        }
    ]
}

• Another comprehensive example

---
name: Example Developer
job: Developer
skill: Elite
employed: True
foods: 
    - Apple
    - Orange
    - Strawberry
    - Mango
languages:
    ruby: Elite
    python: Elite
    dotnet: Lame

Display of python

{
    'name': 'Example Developer',
    'job': 'Developer',
    'skill': 'Elite', 
    'employed': True,
    'foods': [
        'Apple', 'Orange', 'Strawberry', 'Mango'
    ], 
    'languages': {
        'ruby': 'Elite',
        'python': 'Elite',
        'dotnet': 'Lame'
    } 
}

3. Installation of Ansible

• Installation of CentOS YUM

First install EPEL source
 Installation on the main control machine
yum install -y ansible
ansible --version
 Test the installation for success
ansible 192.168.12.1 -m ping -k -u beeworkshop
 Be careful:
- k means ssh uses password authentication (otherwise key authentication)
- u Specifies the username for ssh login
 Or through / etc/ansible/hosts configuration
192.168.12.1 ansible_ssh_user=bee
 To specify ssh login users.
/ The 192.168.12.1 address should be configured in the etc/ansible/hosts file, which is equivalent to whitelist, otherwise no command will be executed.

• Installation of Ubuntu

$ sudo apt-get install software-properties-common
$ sudo apt-add-repository ppa:ansible/ansible
$ sudo apt-get update
$ sudo apt-get install ansible

• pip Installation

$ sudo pip install ansible

4. Ansible configuration file

• /etc/ansible/hosts

# Ex 1: Ungrouped hosts, specify before any group headers.

## green.example.com
## blue.example.com
## 192.168.100.1
## 192.168.100.10

# Ex 2: A collection of hosts belonging to the 'webservers' group

## [webservers]
## alpha.example.org
## beta.example.org
## 192.168.1.100
## 192.168.1.110

# If you have multiple hosts following a pattern you can specify
# them like this:

## www[001:006].example.com

# Ex 3: A collection of database servers in the 'dbservers' group

## [dbservers]
## 
## db01.intranet.mydomain.net
## db02.intranet.mydomain.net
## 10.25.1.56
## 10.25.1.57

# Here's another example of host ranges, this time there are no
# leading 0s:

## db-[99:101]-node.example.com

Ansible specifies the list of hosts that Ansible works by defining the number of hosts and the group rule Inventory. Ansible reads the / etc/ansible/hosts file by default to obtain the controlled host.
If the hosts file is not the default location, you need to use the - i option to specify:

ansible -i /home/beeworkshop/hosts bidder -m ping

localhost is added to Inventory by default.
A host can belong to multiple groups, but priority is needed to avoid conflicts.
If you do not use SSH's default port 22, you need to specify the port

bee.example.com:5555

Use of aliases

jumper ansible_ssh_port=5555 ansible_ssh_host=192.168.1.50

Specify connection type and user name

localhost ansible_connection=local
abc.exam.com ansible_connection=ssh ansible_ssh_user=abc
def.exam.com ansible_connection=ssh ansible_ssh_user=def

• Host variables
  For playbook configuration.

[atlanta]
host1 http_port=80 maxRequestsPerChild=808
host2 http_port=303 maxRequestsPerChild=909

• Group variables
  Group variables cover all members of a group.

[atlanta]
host1
host2
[atlanta:vars]
ntp_server=ntp.atlanta.example.com
proxy=proxy.atlanta.example.com

• group nesting

[atlanta]
host1
host2
[raleigh]
host2
host3
[southeast:children]
atlanta
raleigh
[usa:children]
southeast
northeast
southwest
northwest

• Separating host and group variables
  In order to better specify host and group variables, Ansible supports separating hostname and group variables defined by hosts files separately and storing them in YAML files. Inventory directory and playbook directory can store group_vars and host_vars, but playbook has higher priority.

5. Ansible Common Modules

• Help

ansible-doc -l
ansible-doc -s <module>

• get help
  https://docs.ansible.com/ansible/latest/modules/modules_by_category.html
• Syntax of calling module

ansible operation target-m module name-a module parameter

• Usage of Common Modules

(1) setup
 Get client details
ansible webserver -m setup

(2) copy
 Send files to clients
 Close SELinux on the client
ansible webserver -m command -a "yum install -y install libselinux-python"
ansible webserver -m copy -a "src=/usr/local/src/test.py dest=/tmp owner=root group=root mode 0755 force=yes"

force:
yes coverage
 Copy files when no exists

backup:
Back up the original file before yes overrides, and the backup file contains the time
 No no backup

Path contains / replicates do not contain the directory, only the contents of the directory
 Path does not contain / copy contains the directory

(3) synchronize
 rsync needs to be installed in advance
 Copy files and directories to clients
ansible 192.168.1.21 -m synchronize -a "src=/usr/local/src/ dest=/usr/local/src/ delete=yes compress=yes"
delete=yes makes the content on both sides the same - the new client does not exist, the client deletes differently.
compress=yes open compression
 Path contains / replicates do not contain the directory, only the contents of the directory
 Path does not contain / copy contains the directory

(4) file
 Setting File Catalog Properties
 Group defines the group of file directories
 Model defines permissions for file directories
 Owner defines the owner of the file directory
 Path required option, path
 recurse sets file properties recursively, only valid for directories
 src links to the original file, only for state=link
 dest link target, only for state=link
 force yes: coverage, no: no coverage
 state Link File Status
 link Creates Soft Links
 Create directories if directory directories do not exist
 File is not created even if the file does not exist
 absent deletes directories, files, link files
 Touch with touch command

ansible 192.168.2.1 -m file -a "src=/usr/local/src/test.py dest=/tmp/test.py state=link"
ansible 192.168.2.1 -m command -a 'll /tmp/test.py'
ansible 192.168.2.1 -m file -a "path=/tmp/test.py state=absent"
ansible 192.168.2.1 -m file -a 'path=/tmp/test.py state=touch owner=root group=root mode=0755'
ansible webserver -m file -a  'path=/tmp/test state=directory owner=root group=root mode=0755'