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overall situation	Set from the command line or configuration file
host	By list , The task of collecting or registering facts
paly	stay play And the... Set in the related structure

Variable priority setting ： Narrow areas take precedence over wide areas (play > host > overall situation )

3、 ... and 、 Variable setting and usage

1、 Using variables

2、 stay playbook Directly define variables in

  1 ---
  2 - name: test yml                # Project name 
  3   hosts: westos                 # Remote host list 
  4   vars:                         # Defining variables 
  5     NAME: zzh
  6   tasks:
  7     - name: create user         # Define subprojects 
  8       user:
  9         name: "{
   {NAME}}"        # Using variables

usage ：

3、 Define variables in the file

  1 ---
  2 - name: test yml
  3   hosts: westos
  4   vars_files: user.yml            # File to call variables 
  5   tasks:
  6     - name: create user
  7       user:
  8         name: "{
   {NAME}}"

usage ： So let's create one <user.yml> file , Write the variable name in the file . Call the variables in the file as follows in the script .

4、 Set host variables and manifest variables

  1 ---
  2 - name: test yml
  3   hosts: test                    # The variable to be specified is in the Group 
  4   tasks:
  5     - name: create user
  6       user:
  7         name: "{
   {NAME}}"

Add variables to the list , The variable is only valid for specific groups . How to write it ：[ Group name ：vars]

usage ：

5、 Directory setting variables

group_vars	Manifest variables , In the directory The file name is consistent with the host list name
host_vars	Host variables , In the directory The file name is consistent with the host name

Method 1 ：

Method 2 ：

6. Override variable with command

Be careful ： This method has the highest priority

ansible-playbook test.yml -e "NAME=westos_zzh"

7. Use an array to set variables

fit Multiple variables The definition of

  1 ---
  2 - name: test yml
  3   hosts: test
  4   vars_files: ./user.yml                    # Specify variable storage file 
  5   tasks:
  6     - name: show vars                       # subprojects 1
  7       debug:                                
  8         var: USERLIST['lee']['age']         # Show USERLIST Under the lee Of age The variables in the 
  9 
 10     - debug:                                # subprojects 2
 11         msg: "{
   {USERLIST['westos']}}"       # Show USERLIST Under the westos Partial variables

Create a file to store variables in the same directory .

Show multiple variables

8. Register variables

register Put the module's Output Capture and write to the specified character string in .

  1 ---
  2 - name: test register
  3   hosts: test
  4   tasks:
  5     - name: hostname command
  6       shell:
  7         hostname
  8       register: info                        # Store the output of the subproject as info In the list 
  9 
 10     - name: show messages
 11       debug:
 12         msg: "{
   {info['stdout']}}"            # from info Select output... From the list “stdout” Variable 
 13 
 14     - name: show rc                          # from info Select output... From the list “rc” Variable 
 15       debug:
 16         var: info['rc']

9. Fact variables ——ansible_facts

The following commands can be used to collect the factual information of the controlled host ：

ansible 172.25.254.151 -m setup

The fact variable is ansible Variables automatically detected in the controlled host ;
There is also host related information in the fact variable ;
When it is necessary to use host related information, it is not necessary to collect data , Just call it directly ;
Because the variable information is system information Do not set at will For information collection only , So it is called a fact variable .

  1 ---
  2 - name: test register
  3   hosts: test
  4   tasks:
  5     - debug:
  6         var: ansible_facts['enp1s0']['ipv4']['address']    # Filter the data under the fact variable

Save the value of the variable ：

  1 ---
  2 - name: test register
  3   hosts: test
  4   tasks:
  5     - lineinfile:
  6         path: /mnt/address
  7         line: "{
   { ansible_facts['enp1s0']['ipv4']['address']}}"
  8         create: yes

preservation enp1s0 Network card ipv4 Address to the controlled host </mnt/address> In file

Be careful ： gather_facts: no ## stay playbook Turn off fact variable collection in
This parameter will speed up execution , However, fact variables will not be collected, resulting in inaccurate results or even errors .

10. Magic variable

hostvars:	ansible Internal information of the software
group_names:	The currently managed host is in the same group
groups:	List all groups and hosts in the list
inventory_hostname:	Contains the name of the currently managed host configured in the manifest

The magic variable is ansible Internal variables of the host

ansible localhost -m debug -a 'var=hostvars'        # Show ansible Internal information of the software

ansible test -m debug -a 'var=groups'                # List all groups and hosts in the list 
ansible test -m debug -a 'var=inventory_hostname'    # Contains the name of the currently managed host configured in the manifest 
ansible test -m debug -a 'var=group_names'           # The currently managed host is in the same group

Four 、JINJA2 Templates

Jinja2 yes Python The next widely used template engine . His design idea comes from Django Template engine for , It also extends its grammar and a series of powerful functions . One of the most significant is the addition of sandbox execution function and optional automatic escape function