yaml.md

Yet Another Markup Language

• specification

indentation

2 spaces

data types

• string
• number
• boolean
• list
• map

host: ger-43
datacenter:
location: Germany
cab: "13"
cab_unit: 3

# block-style
list_of_strings:
- one
- two
- three
# flow-style
another_list_of_strings: [one,two,three]

# block-style
map_example:
  - element_1: one
  - element_2: two
# flow-style
map_example2: {element_1: one , element_2: two }

more comples example - list of maps

credentials:
  - name: 'user1'
    password: 'pass1'
  - name: 'user2'
    password: 'pass2'

comment

# this is comment in yaml
user_name: cherkavi # comment after the value
user_password: "my#secret#password"

multiline

• one line string ( removing new line marker )

comments: >
Attention, high I/O
since 2019-10-01.
Fix in progress.

• each line of text - with new line marker ( new line preserving )

downtime_sch: |
2019-10-05 - kernel upgrade
2019-02-02 - security fix

multi documents

---
name: first document

---
name: second document

# not necessary marker ...
...
---
name: third document

place of metadata, header

# this is metadata storage place
---
name: first document

anchor, reference

& - anchor

• • reference to anchor simple reference

---
host: my_host_01
description: &AUTO_GENERATE standard host without specific roles
---
host: my_host_02
description: *AUTO_GENERATE

reference to map

users:
  - name: a1 &user_a1    # define anchor "user_a1"
    manager:
  - name: a2
    manager: *user_a1    # reference to anchor "user_a1"

example with collection

---
host: my_host_01
roles: &special_roles
  - ssh_server
  - apache_server
---
host: my_host_02
roles: *special_roles

another yaml example, anchor reference

base: &base
    name: Everyone has same name

foo: &foo
    <<: *base
    age: 10

bar: &bar
    <<: *base
    age: 20  

TAG

set data type for value

• seq
• map
• str
• int
• float
• null
• binary
• omap ( Ordered map )
• set ( unordered set )

name: Vitalii
id_1: 475123 !!str
id_2: !!str 475123 

assign external URI to tag ( external reference )

should be defined inside metadata

%TAG ! tag:hostdata:de_muc
---
# reference id is: DE_MUC
location: !DE_MUC Cosimabad   

local tag ( reference inside document )