Detailed Inventory

Detailed Inventory

Ansible system may be implemented according to a plurality of simultaneously Inventory file. The file is located /etc/ansible/hosts. The actual use of multiple Inventory can write files when used with -itemporary parameters specified on the line.

This file can not write your own, write more. The allocation of time not only can use local resources, we can use the resources in the cloud.

This file can be written into a variety of formats, commonly used are: the INI , YAML .

Inventory basis: multiple hosts packets

Mean the same thing in the inventory file can INI write can also be used YAML write, but you need to install the corresponding plug-ins.

INI format is this:

mail.example.com

[webservers]
foo.example.com
bar.example.com

[dbservers]
one.example.com
two.example.com
three.example.com

Inside the square brackets is the group name , did not know the name of justice reached see the effect, it is best to let the name reflects: This is what the operating system, which is used to do things, what the general run time.

This file YAML format is written like this:

all:
  hosts:
    mail.example.com:
  children:
    webservers:
      hosts:
        foo.example.com:
        bar.example.com:
    dbservers:
      hosts:
        one.example.com:
        two.example.com:
        three.example.com:

The multiple hosts configured into a plurality of groups

Simultaneously loading system to a plurality of groups, so this effect can be done: a host both a web server , and a database server .

When you can create a group with such an idea:

• To doing

  Application stack, micro-services. For example: Database Servers , Web Servers .

• where is it

  Local DNS server which data center in which region or, storage server storage. For example: East , West .

• What stage

  Development phase, the need to avoid the test line of code. For example: Prod , the Test .

Contains more than three thought YAML for Inventory, the file format can be written like this:

all:
  hosts:
    mail.example.com:
  children:
    webservers:
      hosts:
        foo.example.com:
        bar.example.com:
    dbservers:
      hosts:
        one.example.com:
        two.example.com:
        three.example.com:
    east:
      hosts:
        foo.example.com:
        one.example.com:
        two.example.com:
    west:
      hosts:
        bar.example.com:
        three.example.com:
    prod:
      hosts:
        foo.example.com:
        one.example.com:
        two.example.com:
    test:
      hosts:
        bar.example.com:
        three.example.com:

It can be seen one.example.comin the dbserversgroup, and also in eastthe group, also in prodthe group.

You can also use a nested way to simplify this file:

all:
  hosts:
    mail.example.com:
  children:
    webservers:
      hosts:
        foo.example.com:
        bar.example.com:
    dbservers:
      hosts:
        one.example.com:
        two.example.com:
        three.example.com:
    east:
      hosts:
        foo.example.com:
        one.example.com:
        two.example.com:
    west:
      hosts:
        bar.example.com:
        three.example.com:
# 以上相同        
    prod:
      children:
        east:
    test:
      children:
        west:

If you use this method of shorthand, pay attention to the variables represent all hosts it contains.

Multiple hosts use different ports

If there is no host with the default ssh port, with the port after the host name on the line.

If you want to configure the host port number really is not the default port 22 , the port it is best to go with it.

like this:

badwolf.example.com:5309

If the IP hosts are static and do not change, and when the connection needs to be connected through the tunnel, it can hosts configure the look alias file.

INI file with this:

jumper ansible_port=5555 ansible_host=192.0.2.50
别名    端口号             主机名

YAML file with this:

...
  hosts:
    jumper:
      ansible_port: 5555
      ansible_host: 192.0.2.50

If the host name is written in a unified mode, it can be abbreviated:

INI format:

[webservers]
www[01:50].example.com

YAML format:

...
  webservers:
    hosts:
      www[01:50].example.com:

For digital pattern matching preamble 0 may be added to or removed as needed, before and after the scope is closed interval , the two values can be taken to the boundary.

You can also be defined range of letters:

[databases]
db-[a:f].example.com

You can also select the connection type and the user of each host :

[targets]

localhost              ansible_connection=local
other1.example.com     ansible_connection=ssh        ansible_user=mpdehaan
other2.example.com     ansible_connection=ssh        ansible_user=mdehaan
主机                    连接类型                       连接用户

As mentioned above, these are just a simplified method set in the inventory file and later on we will discuss how to store them in host_vars each file in the directory.

Refers to a variable with a host: the host variable

The host can also be used to refer to variables and variables are now specified in the back of the playbook will be used.

INI format:

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

YAML format:

atlanta:
  host1:
    http_port: 80
    maxRequestsPerChild: 808
  host2:
    http_port: 303
    maxRequestsPerChild: 909

With variable refer to multiple hosts: set of variables

Variables can also be applied to a whole group.

INI format:

[atlanta]
host1
host2

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

YAML format:

atlanta:
  hosts:
    host1:
    host2:
  vars:
    ntp_server: ntp.atlanta.example.com
    proxy: proxy.atlanta.example.com

Set of variables Inheritance: sub-set of variables

Subgroups may be arranged, and the use of a variable subset

	INI format	YAML format
Subgroups	:children	children:
Sub-set of variables	:vars	vars:

INI format:

[atlanta]
host1
host2

[raleigh]
host2
host3

[southeast:children]
atlanta
raleigh

[southeast:vars]
some_server=foo.southeast.example.com
halon_system_timeout=30
self_destruct_countdown=60
escape_pods=2

[usa:children]
southeast
northeast
southwest
northwest

YAML format:

all:
  children:
    usa:
      children:
        southeast:
          children:
            atlanta:
              hosts:
                host1:
                host2:
            raleigh:
              hosts:
                host2:
                host3:
          vars:
            some_server: foo.southeast.example.com
            halon_system_timeout: 30
            self_destruct_countdown: 60
            escape_pods: 2
        northeast:
        northwest:
        southwest:

Several default group

There are two default groups: All and ungrouped .

all contain all hosts

ungrouped comprising belongs to all hosts group

Each host belongs to at least two groups

Despite all and ungrouped always existed, but they may be implicit, not appear in group_names group list of classes.