Inventory

Question 1

Define inventory

Answer 1

The collection of hosts that Ansible manages

Question 2

Simplest inventory content

Answer 2

ontartio.example.com
pei.example.com
nova-scotia.example.com

Question 3

One host is always part of your inventory. Which one?

Answer 3

localhost

Question 4

What is the difference between connecting to locahost and any other machine?

Answer 4

Ansible uses SSH for other hosts. For locahost it does not go through SSH. It uses local connection instead.

Question 5

List Ansible behavioral inventory parameters

Answer 5

1) ansible_host
2) ansible_port
3) ansible_user
4) ansible_password
5) ansible_connection
6) ansible_private_key_file
7) ansible_shell_type
8) ansible_python_interpreter
9) ansible_*_interpreter

Question 6

What are behavioral inventory paramaters?

Answer 6

behavioral invetory paramaters are variables that can be used to refine the definition of a host and how ansible should connect to it.

Question 7

what is the name of the the default group?

Answer 7

all also named *

Question 8

Ansible command to get dates on all managed nodes

Answer 8

ansible all - a “date”

Question 9

What is the format of an inventory file?

Answer 9

ini file format

Question 10

Define a group web with hosts toronto.example.com and vancouver.example.com

Answer 10

[web]

toronto. example.com
vancouver. example.com

Question 11

I have 3 hosts running on the same 127.0.0.1 IP but different ports. My goal is to configure them. Explain why the following group configuration will not work?
And how to you resolve it?

[myservers]

127. 0.0.1: 2000
128. 0.0.1: 2001
129. 0.0.1: 2002

Answer 11

Ansible inventory can associate only a single host with 127.0.0.1.
To resolve it use aliases

[myservers]
server1 ansible_host=127.0.0.1 ansible_port=2000
server2 ansible_host=127.0.0.1 ansible_port=2001
server3 ansible_host=127.0.0.1 ansible_port=2002

Question 12

Define a group staging that contains two other groups: web and lb.

Answer 12

[staging:children]
lb
web

Question 13

Define a group web that includes all servers web1.example.com to web20.example.com

Answer 13

[web]

web[1:20].example.com

Question 14

Define two variables user and password for a group web

Answer 14

[web:vars]
user=macabo
password=eboubolo

Question 15

What are possible types of a ansible variable?

Answer 15

Booleans, strings, dictionaries, lists

Question 16

What are limitations of specifying variables in inventory files?

Answer 16

1) inventory files only support string and booleans as variable values
2) crowded inventory file

Question 17

How do you define variables to prevent shortcommings of defining them in inventory file?

Answer 17

Define them in YAML files located under folders group_vars or host_vars.

Question 18

what is the format of a file located under group_vars.

Answer 18

YAML

Question 19

What are possible parameters of a dynamic inventory script?

Answer 19

• -host=hostname (for showing host details/variables of individual host)
• -list (for listing groups)

Question 20

what is the aim of the –host parameter of an inventory script?

Answer 20

for showing host details/variables of individual host. Result is a json that shows variables and their values.

Question 21

what is the aim of the –list parameter of an inventory script?

Answer 21

returns all groups along with their hosts. result is a json object of group names to host list.

Question 22

How does Ansible retrieves variables for a speicific host, given –list returns list of groups?

Answer 22

–list includes an optimization that includes the meta section. meta is a json object of host to their variables.

Question 23

What measures are needed to use static and dynamic inventory files with a single playbook?

Answer 23

1) Put all files in the same folder
2) make the dynamic inventory file executables
3) Specify the folder location in ansible configuration file

Question 24

Write a fragment to configure inventory location in ansible config file

Answer 24

[defaults]

inventory = my_inventory

Question 25

When are dynamic inventory scripts invoked during the execution of a playbook? What is the implication?

Answer 25

Right before the playbook itself is invoked. the implication is that if the playbook cannot configure hosts that it spins up itsself.

Question 26

what is add_host used for?

Answer 26

add_hosts is used to add a host to an inventory dynamically during the execution of the playbook. It is different than dynamic inventory that generates all its hosts prior to the playbook being launched.

add_host can be used for instance to bring up a new vagrant machine and configure it within the same script.

Question 27

Does add_host modify the inventory file?

Answer 27

No. It only add to the runtime inventory and the change is not persisted to a file.

Question 28

explain group_by

Answer 28

Used to group nodes using some facts. For instance group by distribution. Can also be seen as a way to achieve conditional behaviour.

Question 29

How do you tell Ansible to ignore files with extension txt when loading dynamic inventories from a folder

Answer 29

add txt to the list of extensions to skip in ansible.cfg

inventory_ignore_extension

Question 30

What could be the use of empty groups in dynamic inventory file?

Answer 30

Empty group can be used to declare the group if the content is provided by a dynamic inventory script.

Question 31

Create ansible.cfg that sets the inventory location as /home/paoblo/ansible/ansible.cfg

Answer 31

[defaults]

inventory= /home/paoblo/ansible/ansible.cfg