yaml_Ansible_6

 yaml tags

In YAML, tags are a way to explicitly define the data type of a value. 

Normally YAML auto-detects types (like string, int, boolean), but tags let you override or clarify that behavior.

Basic Syntax of YAML Tags

Tags are written using !! before a value:

Integer $ count: !!int 10

Float $ count: !!int 10

boolean $ enabled: !!bool yes

Null $ value: !!null null

String $ name: !!str 12345

yaml_Ansible_5

 Date and Timestamps in yaml

YYYY-MM-DD #standard date format 

YYYY-MM-DDTHH:MM:SSZ  # Full Timestamps

T = Seprates Date and Timestamps

Z = for UTC Timestamps

iso8601 format

YYYY-MM-DDTHH:MM:SS+(OR)-HH:MM (The offset timezone (-5))

Ansible_9 Automation Execution Environment (EE)

 An Automation Execution Environment (EE) is a portable, consistent runtime for running Ansible automation. Think of it as a pre-built container image (like Docker/Podman) that already has everything your automation needs.

🔹 Simple Idea

Instead of installing Python, Ansible, collections, and dependencies on every control node, you package everything into one environment and run it anywhere.

Ansible execution environments (EE) were introduced in Ansible Automation Platform 2 to provide a defined, consistent and portable environment for executing automation jobs.

Execution environments are basically Linux container images that help execute Ansible playbooks.

The container images for the execution environments contain the necessary components to execute Ansible automation jobs. These include Python, Ansible (ansible-core), Ansible Runner, required Python libraries, and dependencies.

When you install Ansible Automation Platform, the installer deploys the following container images whether you're in a connected or an unconnected installation:

* The ee-29-rhel8 image contains Ansible 2.9 to use with older Ansible playbooks.

* ee-minimal-rhel8 is the minimal container image with ansible-core and basic collections.

* ee-supported-rhel8 is the container image with ansible-core and automation content collections supported by Red Hat.

Ansible Automation Platform's default container images let you start doing automation without any additional configurations.

You can follow the standard container image build process for building execution environment container images, but Ansible Automation Platform also includes a command-line utility called ansible-builder to build container images for custom execution environments.

The ansible-builder tool can be installed from the upstream Python repository or the Red Hat RPM repository:

## Install ansible-builder utility

$ pip3 install ansible-builder

## Ansible Automation Platform repository subscription is required

$ sudo dnf install ansible-builder

The ansible-builder helps you build container images with the definition file execution-environment.yml.

A typical execution-environment.yml contains the base container image (EE_BASE_IMAGE), ansible.cfg, and other dependency file details:

---

version: 1

build_arg_defaults:

EE_BASE_IMAGE: 'registry.redhat.io/ee-minimal-rhel8:latest'

ansible_config: 'ansible.cfg'

dependencies:

galaxy: requirements.yml

python: requirements.txt

additional_build_steps:

append:

- RUN microdnf install which

Once you've prepared the execution-environment.yml, execute the ansible-builder build command to create a build context that includes the Containerfile.

$ ansible-builder build --tag my_custom_ee

Running command:

podman build -f context/Containerfile -t my_custom_ee context

Complete! The build context can be found at: /home/ralagarasan/ansible-aap-demo/context

Two options to build and use custom execution environments with Ansible Automation Platform: building and transferring the container image or creating a custom environment.

1. Build and transfer a container image

2. Create a custom execution environment in an unconnected environment

1. Build and transfer a container image

You can create a container image from a connected machine (for example, a developer workstation) with all the dependencies inside and transfer it to the private automation hub (or another supported registry).

Step 1. Create and archive the container image from a connected machine:

## build the container image

$ ansible-builder build --tag my_custom_ee

## Save the container image as archive file

$ podman save --quiet -o my_custom_ee-1.0.tar localhost/my_custom_ee:1.0

Step 2. Copy the archived container image (for example, my_custom_ee-1.0.tar) to the target

Step 3. Load the container image from the TAR file to the system on the unconnected machine, and build the container image: $ podman load -i my_custom_ee-1.0.tar

Step 4. Follow the tag and push process for private automation hub.

$ podman login automationhub22-1.lab.local

Tag the local container image with the private automation hub path:

$ podman tag localhost/network-ee:1.0 automationhub22-1.lab.local/network-ee:1.0

Push the image to the private automation hub (registry):

$ podman push automationhub22-1.lab.local/network-ee:1.0

2. Create a custom execution environment in an unconnected environment

Step 1. Transfer the dependencies to the target unconnected system

Step 2. Prepare the Containerfile with instructions to build the container image for the execution environment:

## Containerfile for custom execution environment

ARG EE_BASE_IMAGE=registry.redhat.io/ansible-automation-platform-22/ee-minimal-rhel8:latest

ARG EE_BUILDER_IMAGE=registry.redhat.io/ansible-automation-platform-22/ansible-builder-rhel8

FROM $EE_BASE_IMAGE

ADD ansible.cfg ansible.cfg

ADD python-packages.tar python

RUN python3 -m pip install -r python/python-packages/requirements.txt --find-links=python/python-packages/ --no-index

Step 3. Build the container image using Podman:

$ podman build -f Containerfile -t localhost/network-ee:1.0

[...]

Looking in links: python/python-packages/

Processing ./python/python-packages/pan_os_python-1.7.3-py2.py3-none-any.whl

Processing ./python/python-packages/pan_python-0.17.0-py2.py3-none-any.whl

Installing collected packages: pan-python, pan-os-python

[...]

Successfully tagged localhost/network-ee:1.0

01e210e05a60dcf49c1b4a2b1bf1e58c49a487823b585233a15d1ecd66910bab

The TAR file is copied, extracted, and the content is installed inside the image.

[Thanks Redhat](https://www.redhat.com/en/blog/ansible-execution-environment-unconnected)

Ansible_8

Ansible_8

Use Python virtual environments for Ansible


To avoid version conflicts (Ansible, Python libs, collections) and its safe upgrades/testing without breaking system Python.


Intall Required Packages
# dnf install -y python3 python3-pip python3-virtualenv # optional suggestion pkges gcc python3-devel libffi-devel openssl-devel
Create virtual environment
# python3 -m venv ansible-env #This creates a folder ansible-env/ with isolated Python
If venv is missing # virtualenv ansible-env

Activate the environment
# source ansible-env/bin/activate
prompt will change like below
(ansible-env) user@host:~$

Install Ansible inside venv
$ pip install --upgrade pip
$ pip install ansible
$ ansible --version
$ ansible-galaxy collection install community.general
$ ansible-galaxy collection install ansible.posix
$ ansible-galaxy collection install community.vmware
$ ansible-playbook -i inventory.ini playbook.yml

Deactivate
$ ansible-playbook -i inventory.ini playbook.yml

eg
python3 -m venv /home/ralagarasan/uc-01
pip freeze > requirements.txt
pip install -r requirements.txt

yaml_Ansible_4_map

 Map Structure

Map refers to Dictionary or Key-Value pair structure,

Map Structured-data

A YAML map (mapping) is basically a key → value structure (like a dictionary in Python or JSON object).

name: Alagarasan

role: DevOps Consultant

experience: 8

👉 Here:

name, role, experience → keys

Values → strings / numbers

- name: Create VM

hosts: localhost

vars:

vm_name: test-vm

vm_cpu: 2

👉 Here:

vars is a map

Inside it → vm_name, vm_cpu are keys

Types of Maps

Inline Map

Block Map

Inline Map

person: {name: Alagarasan, role: DevOps Consultant, experience: 8}

Block Map

person:

name: Alagarasan

role: DevOps Consultant

experience: 8

Access full map

- debug:

var: person

Access individual values

- debug:

msg: "{{ person.name }}"

- debug:

msg: "{{ person.role }}"

🔹 Nested Map (Map inside Map)

Inside map we always have key value pairs. We can have multiple key value pairs inside a map. We can also have a map inside a map which is called nested map.

employee:

name: Alagarasan

role: DevOps Consultant

skills:

primary: Ansible

secondary: AWS

Access nested value

- debug:

msg: "{{ person.address.city }}"

👉 Structure:

employee → parent key

Inside it → another map

Map with list

person:

name: Alagarasan

skills:

- Ansible

- Docker

- Kubernetes

Nested Map + List (Real-world 🔥🔥)

servers:

- name: web01

config:

ip: 192.168.1.10

ports:

- 80

- 443

- name: web02

config:

ip: 192.168.1.11

ports:

- 8080

👉 Access:

{{ servers[0].config.ip }}

{{ servers[0].config.ports[1] }}

Yaml_Ansible_3_list

 List (Array) # Lists start with - (dash + space), Indentation matters

A sequence of items, represented as a list (array) in YAML.

Lists can be defined using either block style (with dashes) or inline style (with square brackets).

List Multiple-items

Simple List (Basic)

servers:

- web1

- web2

- db1

Inline List (Flow Style)

servers: [web1, web2, db1]

Nested List

matrix:

- - 1

- 2

- - 3

- 4

List of Maps (Very Important in Ansible 🚀)

users:

- name: John

age: 25

- name: Alice

age: 30

🔥 How to "call" (access) list of maps

Access full list {{ users }}

Access first item {{ users[0] }}

Access specific value {{ users[0].name }} # 👉 Output: John

Loop through list (Most important 🚀)

- name: Print users

debug:

msg: "{{ item.name }} is {{ item.age }} years old"

loop: "{{ users }}"

List inside Map

employee:

name: John

skills:

- Python

- Ansible

- Docker

👉 Here:

employee → map

skills → list inside the map

Access full list {{ employee.skills }}

Access specific item (index) {{ employee.skills[0] }} #👉 Output: Python

Loop through the list

- name: Print skills

debug:

msg: "{{ item }}"

loop: "{{ employee.skills }}"

Use inside message

- name: Print employee info

debug:

msg: "{{ employee.name }} knows {{ employee.skills[1] }}"

👉 Output: John knows Ansible

Structure How to Access

Map → key map.key

List → index list[0]

Map → List map.list_key[0]

YAML_Ansible_2

 

Types of YAML Strings

YAML supports 4 main styles:

🟢 1. Plain Strings (No quotes)

🟡 2. Single-Quoted Strings ' '

🔵 3. Double-Quoted Strings " "

🟣 4. Multi-line Strings (VERY IMPORTANT 🔥)

🟢 1. Plain Strings (No quotes)

name: Alagarasan

role: DevOps Engineer

company: TCS

🟢 2. Double-Quoted Strings

message: "Start\nEnd" # \n is treated as a newline character

👉 Output

Start

End

quote: "He said, \"YAML is easy\"". # \" is treated as a literal double quote or \" lets you escape double quotes

👉 Output

He said, "YAML is easy"

tab: "Hello\tDevOps" # \t is treated as a tab character

quote: "He said \"Hi\"" # \" is treated as a literal double quote

path: "C:\\Program Files\\App"

👉 Output

C:\Program Files\App

💡 Why?

\ is a special character → must escape as \\

Prevent Boolean Conversion

value: "yes"

👉 Output

yes (string)

Tabs / Formatting # \t = tab spacing

text: "Name:\tAlagarasan"

👉 Output

Name: Alagarasan

Multi-line Formatting (Inline)

msg: "Line1\nLine2\nLine3"

👉 Output

Line1

Line2

Line3

🟢 3. Single-Quoted Strings # Everything is treated literally,No special character processing

In YAML, single-quoted strings (' ') are used when you want the content to be taken literally — no escape sequences, no special processing.

name: 'Alagarasan'

city: 'Chennai'

✔ Everything inside ' ' is treated as plain text.

Special Characters (No escaping needed)

path: '/usr/local/bin'

message: 'Hello: World!'

✔ Characters like :, /, ! are safe inside single quotes.

Quotes Inside String

To include a single quote inside, double it ('')

text: 'It''s DevOps'

👉 Output: It's DevOps. # Only one escape:

No Escape Sequences

newline: 'Line1\nLine2'

👉 Output (literal, NOT new line):

Line1\nLine2

❌ \n is NOT interpreted

✔ It stays as plain text

admin: 'true'

🔍 What’s happening here?

In YAML, certain words are reserved keywords (called boolean values):

true, false

yes, no

on, off

If you write:

admin: true

👉 YAML interprets it as a boolean, not a string.

🧠 Why use single quotes?

When you write:

admin: 'true'

👉 Now YAML treats it as a string, not a boolean.

Value written YAML interprets as

true Boolean true

'true' String "true"

"true" String "true"

admin: 'true' # string

enabled: true # boolean

Leading / Trailing Spaces Preserved

value: ' hello '

👉 Output:

" hello "

When to Use Single Quotes

Use ' ' when:

You want literal values

You don’t need escape sequences

String contains special characters like :, #, !

You want safe, predictable parsing

🟣 4. Multi-line Strings (VERY IMPORTANT 🔥)

Literal block (|) → preserves format

message: |

Hello

DevOps

Team

👉 Output:

Hello

DevOps

Team

Folded block (>) → merges lines

message: >

Hello

DevOps

Team

👉 Output:

Hello DevOps Team

YAML_Ansible_1

 Binary Data

binary data

In YAML, binary data is used to store: 👉 Non-text data (images, files, certificates, keys, etc.). Since YAML is text-based, binary data is encoded using: 👉 Base64 encoding

Binary data can be represented in YAML using Base64 encoding. This allows you to include binary data, such as images or files, within a YAML document.

converted → Base64 → stored as text

Srtucture:

file_content: !!binary |

SGVsbG8gRGV2T3Bz

file_data: !!binary |

R0lGODlhAQABAIAAAAUEBAgKACwAAAAAAAAQABAAACAkQBADs=

What happens internally:

Original data → Hello DevOps

Encoded → SGVsbG8gRGV2T3Bz

YAML stores → text safely

eg

certificate: !!binary |

MIIDdzCCAl+gAwIBAgIEbM2Q0jANBgkqhkiG9w0BAQsFADBoMQswCQYDVQQG

EwJVUzELMAkGA1UECBMCQ0ExETAPBgNVBAcTCFNhbiBKb3NlMRgwFgYDVQQK

EwwgRXhhbXBsZSBDb3JwMQ8wDQYDVQQLEwZJVCBEZXB0MRgwFgYDVQQDEw9l

eGFtcGxlLmNvbTAeFw0yMTA1MDkwODI4NDJaFw0zMTA1MDcwODI4NDJaMGgx

CzAJBgNVBAYTAlVTMQswCQYDVQQIEwJDQTERMA8GA1UEBxMIU2FuIEpvc2Ux

GDAWBgNVBAoTD0V4YW1wbGUgQ29ycDEPMA0GA1UECxMGSUQgRGVwdDEYMBYG

A1UEAxMPZXhhbXBsZS5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEK

AoIBAQC7mLhHjZyqfXlH65s8v1Z9Xy+5n2u7v1z9X9X9X9X9X9X9X9X9X9X9X

apiVersion: v1

kind: Secret

data:

username: YWRtaW4=

password: cGFzc3dvcmQ=

to Decode Base64

Base64 → Decoded data

# echo "password" | base64

# cGFzc3dvcmQ=

# echo cGFzc3dvcmQ= | base64 --decode

# password

# echo cGFzc3dvcmQ= | base64 -d

# password

YAML decodes the Base64 encoded data back to its original form when it is read or processed.

yaml_Ansible

 YAML Data Types

YAML organizes data using three basic data types: scalars, sequences, and maps. Each of these data types has its own syntax and structure.

1. Scalars

A scalar is a single value, such as a string, number, or boolean. Scalars can be represented in various ways in YAML, including plain style, double-quoted style, and single-quoted style.

name: Alagarasan

age: 30

is_devops_consultant: true

In the above example, name is a string scalar, age is a numeric scalar, and is_devops_consultant is a boolean scalar.

Key value

key: value

key = name

: = Seprator. # Space after colon is mandatory

value = data

String

Text values (quoted or unquoted)

name: Alagarasan

role: "DevOps Engineer"

company: 'TCS'

Integer (Number)

Numeric values without a decimal point (whole numbers)

age: 30

experience: 8

Float (Number)

Numeric values with a decimal point (floating-point numbers)

cpu_usage: 75.5

version: 1.2

Boolean

True or false values

is_active: true

is_admin: false

Null (Empty value)

null is not a string, It represents absence of value

Null (Empty value)

null means:👉 No value / empty value / nothing assigned

~ is a shorthand for null in YAML. It represents the absence of a value, similar to null in other programming languages. When you see ~ in a YAML file, it indicates that the value is intentionally left empty or not assigned.

value1: null

value2: Null

value3: NULL

value4: ~

value5:

eg

user:

name: Alagarasan

middle_name: null

nickname: ~

age: 30

is_active: true

NAN (Not a Number)

NaN stands for: Not a Number. It is a special floating-point value that represents an undefined or unrepresentable value, such as the result of dividing zero by zero.

result: .nan

result: .NaN

result: .NAN

eg

metrics:

cpu_usage: 75.5

memory_usage: .nan

👉 Here:

cpu_usage → valid number

memory_usage → undefined / not measurable

.infinite (INF)

INF stands for: Infinity. It is a special floating-point value that represents an infinitely large number

positive_infinity: .inf

negative_infinity: -.inf

also_positive_infinity: .INF

also_negative_infinity: -.INF

Positive vs Negative Infinity

positive: .inf

negative: -.inf

👉 Meaning:

.inf → +∞

-.inf → −∞

yaml

YAML
YAML (YAML Ain’t Markup Language) is a human-readable data format.

Supports 2 tpype of extension
<file_name>.yaml
<file_name>.yml

yaml is case sensitive. So we have to be careful while writing the yaml file. We have to use the same case for the keys and values.

yaml is not a programming language, it is a data serialization language. It is used to represent data in a structured format. It is commonly used for configuration files, data exchange between languages with different data structures, and for storing data in a human-readable format.

yaml is a superset of JSON, which means that any valid JSON file is also a valid YAML file. However, YAML has additional features that make it more powerful and flexible than JSON.