Linux Nine Yin canon of nine yin Bones claw fragment 5 (ansible usage two playbook and YAML syntax)

Playbook is a list of one or more "play"

The main function of play is to dress up a pre-set host as a role defined in advance through the task in ansible. Fundamentally, the so-called task is nothing more than a call to Ansible's module. By organizing multiple play in one playbook, you can connect them to run in a pre-programmed mechanism.

Playbook use Yaml language to write each ansible Playbook is a yaml format file, so to learn to write a script (Playbook), we first understand the basic use of YAML syntax

One, Yaml introduction

YAML is a highly readable format for expressing data sequences in Ali. Yaml references a number of other languages, including: XML,

C language, Python, Perl, e-mail format RFC2822, and so on. Clark Evans published the first of its kind in 2001

Language, in addition ingy d?t NET and Oren Ben-kiki are also common designers of this language

Second, the characteristics

Good readability of Yaml

The interactivity between Yaml and scripting language is good

YAML uses the data type of the implementation language

YAML has a consistent information model.

Yaml is easy to implement

YAML can process based on streams

Yaml has strong expressive ability and good extensibility

YAML Syntax Format:

1. In a single file, multiple files can be distinguished by three consecutive hyphen (--). In addition, there is a choice of three consecutive dot numbers

( ... ) Used to indicate the end of a file

2. The second line begins to write the contents of the playbook normally, it is generally suggested that the Playbook function

3. Comment Code using the # number

4. Indentation must be uniform, not space and tab mix

5. The level of indentation must also be consistent, the same indentation represents the same level, the level of the program discrimination configuration is by indenting the knot

Line-up to achieve

6.YAML file content is consistent with the Linux system case-sensitivity, is case-sensitive, and the k/v value is case-insensitive

The value of the 7.k/v can be written in either the same or a newline. Peer use: Separate

8.V is a string, but it's another list.

9. A complete code block function requires minimum elements to include Name:task

10. A name can consist of only one task

11.YAML file extension is usually yml or Yaml

Introduction to YAML Syntax:

List

List: Lists, all of whose elements begin with "-"

Example:

# A List of tasty fruits

–apple

–orange

–strawberry

–mango

Dictionary

Dictionary: A dictionary, usually consisting of multiple keys and value

Example:

—

# an Employee record

Name:example Developer

Job:developer

Skill:elite

You can also place key:value in {} to represent, separating multiple key:value

Example:

—

# an Employee record

{name:example Developer, job:developer, Skill:elite}

Third, the script playbook

Playbook Core elements:

hosts: List of remote hosts executed

tasks: Task List

varniables: Built-in variables or custom variables are called in Playbook

Templates: Templates that can replace variables in template files and implement some simple logic files

handlers: Used in conjunction with notify, the action triggered by a specific condition, satisfies the condition to execute, otherwise does not execute

tags: a tag that specifies a task execution that selects some code in the run playbook. The ansible has idempotent nature. So

will automatically skip the parts that are not changed. At this point, if you are sure that it has not changed, you can skip these code snippets through tags

Hosts:

role:each play in playbook is intended to allow one or more hosts to use a specified user

Identity execution tasks. Hosts are used to specify the host to perform the specified tasks, which must be defined in the host manifest

Can be in the following form:

One.example.com

One.example.com:two.example.com

192.168.1.50

192.168.1.*

Websrvs:dbsrvs Two-group set

Websrvs:&dbsrvs intersection of two groups

Webservers:!dbsrvs in Websrvs group, but not in Dbsrvs group

Example:

–hosts:websrvs:dbsrvs

Remote_user

function: can be used in host and task. You can also perform tasks on the remote host by specifying how it is sudo.

It can be used for play global or a task, and even when sudo is specified using Sudo_user to specify sudo

User

–hosts:websrvs

Remote_user:root

Tasks

–name:test Connection

Ping:

remote_user:magedu

Sudo:yes default sudo is root

Sudo_user:wang sudo to Wang

tasks:

Role: Task List

Format: module:arguments

Note:the shell and command modules are followed by commands, not key=value

Check playbook:

Ansible-playbook-c file.yml

How to run Playbook:

Ansible-playbook <filrname.yml> ... [Options]

Options

–check only detects changes that may occur, but does not actually operate

–list-hosts List the hosts running the task

–limit Host list is only performed for hosts in the host list

-V,-VV,-VVV Show detailed procedures

  

One of the simplest playbook to include is the base component host, Remote_user, tasks

Example 1:

Vim Http.yml

—

–hosts:websrvs

Remote_user:root

Tasks

–name:create New File

File:name=/data/newfile State=touch

–name:create New File

User:name=test2 System=yes Shell=/sbin/nologin

–name:install Package

Yum:name=httpd

–name:copy Index

Copy:src=/var/www/html/index.html dest=/var/www/html/

–name:start Service

SERVICE:NAME=HTTPD state=started Enabled=yes

Example: Create a simple script and execute

Tags tags

Task The task can also be labeled with "tags", which can then be invoked with the-T specified on the ansible-playbook command

Example 2: Using tags

Vim Http.yml

—

–host:websrvs

Remote_user:root

Tasks

–name:install httpd Package

Yum:name=httpd

Tags:inshttpd

–name:copy conf File

Copy:src=files/httpd.conf Dest=/etc/httpd/conf/backup=yes

Tags:cphttpd

–name:start Service

SERVICE:NAME=HTTPD STATE=STARTD Enable=yes

Tags:rshttpd

ansible-playbook-t rshttpd httpd.yml separate execution rshttp

Linux Nine Yin canon of nine yin Bones claw fragment 5 (ansible usage two playbook and YAML syntax)