// YAML
 microservice:
   - app: user-authentication
     port: 9000
     version: 1.0

// XML
<microservices>
  <microservice>
    <app>user-authentication</app>
    <port>9000<port>
    <version>1.0<version>
  </microservice>
</microservices><>


// JSON
{
  microservices: [
    {
      app: "user-authentication",
      port: 9000,
      version: '1.0'
    }
  ]
}
                      

• key-value pairs
• objects
• comments
• lists
• booleans
• multi line strings
• environment variables

key-value pairs
metadata = object
labels = object
spec = object
containers = list of objects

# Minus sign (-) is used to indicate a list item in YAML syntax.
# It signifies that "microservice" is a list and each item in the list is denoted by a hyphen followed by a space. Each item in the list represents a separate microservice.


microservices:
  - user-authentication
  - shopping-cart

microservice1s:
  - app: shopping-cart
    port: 9000
    versions: [1.9, 2.0, 2.1]

singleLine: >
  this is a single line.
  that should be interpreted into single line.

multipleLine: |
  this is part of  multiple lines .
  these are real multiple lines.

# using dollar($) sign before environmental variables
command:
  - '/bin/sh'
  - -ec
  - >-
    mysql -h 127.0.0.1 -u root -p$MYSQL_ROOT_PASSWORD -e 'SELECT 1'

# use double curly brackets around the placeholder and this value gets replaced using template generator
apiVersion: v1
kind: Pod
metadata:
  name: { { .Values.service.name } }

# in one yaml file, you can define multiple components  and
# you can separate these components using three dishes like ---
---
apiVersion: v2
kind: Pod


apiVersion: v1
kind: Pod
data:
  mosquitto.conf: |
    log_dest stdout
    log_type all
    log_timestamp true
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  containers:
  - name: nginx-container
    image: nginx
    ports:
    - containerPort: 80
    volumeMounts:
    - name: nginx-vol
      mountPath: /usr/nginx/html
  - name: sidebar-container
    image: some-image/curl
    command: ["/bin/sh"]
    args: ["-c", "echo Hello"]