In k8s, yaml files are generally used to create pod s that meet our expectations
Called resource list

Brief description
Is a highly readable format used to express data sequences. YAML actually means: it is still a markup language, but in order to emphasize this language, count
Data as the center, rather than focusing on markup language

Basic grammar
The Tab key is not allowed when indenting, only spaces are allowed
The number of indented spaces is not important, as long as the elements of the same level are aligned to the left
#The identifier comment, from this character to the end of the line, will be ignored by the interpreter

Data structures supported by YAML
Object: a collection of key value pairs, also known as mapping / hashes / dictionary
Array: a set of values arranged in order, also known as sequence / list
scalars: single, non separable value
Object type: a set of key value pairs of an object, represented by a colon structure

name: Steve
age: 18

Yaml also allows another way to write all key value pairs as an inline object

hash: { name: Steve, age: 18 }

Array type: a group of lines beginning with a conjunction line to form an array

animal
- Cat
- Dog

Arrays can also use inline representation

animal: [Cat, Dog]

Composite structure: objects and arrays can be used together to form a composite structure

anguages:
 - Ruby
 - Perl
 - Python
 websites:
 YAML: yaml.org
 Ruby: ruby-lang.org
 Python: python.org
 Perl: use.perl.org

Scalar: scalar is the most basic and non separable value. The following data types are scalar

1 string Boolean integer floating point number Null
2 time and date

Values are expressed directly in literal form

number: 12.30

Boolean values are represented by true and false

isSet: true

null is represented by ~

parent: ~

The time is in ISO8601 format

iso8601: 2001-12-14t21:59:43.10-05:00

The date is represented by year, month and day in compound iso8601 format

date: 1976-07-31

YAML allows the use of two exclamation marks to cast data types

 !!str 123
 !!str true

character string
Strings are not quoted by default

str: This is a line of string

If the string contains spaces or special characters, you need to put them in quotation marks

str: 'Content: String'

Single quotation marks and double quotation marks can be used, and double quotation marks will not escape special characters

s1: 'content\n character string'
s2: "content\n character string"

If there are still single quotation marks in single quotation marks, two single quotation marks must be used continuously to escape

str: 'labor''s day'

The string can be written in multiple lines. Starting from the second line, there must be a single space indentation. Line breaks are converted to spaces

str: This is a paragraph
 Multiline
 character string

For multiline strings, you can use | to preserve line breaks or > to collapse line breaks

this: |
Foo
Bar
that: >
Foo
Bar

• Means to keep the line break at the end of the text block, - means to delete the line break at the end of the string

s1: |
Foo
s2: |+
Foo
s3: |-
Foo

Explanation of common fields in resource list

View detailed resource help information

[root@k8s-master01 ~]# kubectl explain pod
[root@k8s-master01 ~]# kubectl explain pod.apiVersion
KIND:     Pod
VERSION:  v1

FIELD:    apiVersion <string>

DESCRIPTION:
     APIVersion defines the versioned schema of this representation of an
     object. Servers should convert recognized schemas to the latest internal
     value, and may reject unrecognized values. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#resources

Resource list format

apiVersion: group/apiversion # If no group name is given, the default is core. You can use kubectl api-
versions # Get the version information of all apiversions on the current k8s Version (each version may be different)
kind:
#Resource category
metadata:  #Resource metadata
name
namespace
lables   #label
annotations
# The main purpose is to facilitate users to read and search
spec: # Desired state
status: # In the current status, this field is maintained by Kubernetes, and cannot be defined by users

Write a pod yaml

apiVersion: v1
kind: Pod
metadata:
 name: nginx
 labels:
    app: nginx
    version: v1
spec:
 containers:
  - name: nginx
    image: at.harbor.com/library/nginx:v1

[root@k8s-master01 ~]# kubectl  apply -f pod.yaml 
pod/nginx created

view log
kubectl log pod name - c container name

[root@k8s-master01 ~]# kubectl  log nginx -c nginx
log is DEPRECATED and will be removed in a future version. Use logs instead.
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Configuration complete; ready for start up

Start the error report. You can use this command to view the information of the container

[root@k8s-master01 ~]# kubectl  describe pod nginx

Delete pod

[root@k8s-master01 ~]# kubectl  delete pod nginx

New pod

[root@k8s-master01 ~]# kubectl  create -f pod.yaml 
pod/nginx created

Common commands for resource lists

Get apivision version information

[root@k8s-master01 ~]# kubectl api-versions

Get apiVersion version information of the resource

[root@k8s-master01 ~]# kubectl  explain pod
KIND:     Pod
VERSION:  v1

Get field settings help document

[root@k8s-master01 ~]# kubectl  explain pod
KIND:     Pod
VERSION:  v1

Field configuration format
#Represents the string type

apiVersion <string>

#Indicates that multiple fields need to be nested

metadata <Object>

#Represents a mapping consisting of k:v

labels <map[string]string>

#Represents a list of strings

finalizers <[]string>

#Represents a list of objects

ownerReferences <[]Object>

#Boolean type

hostPID <boolean>

#Integer

priority <integer>

#If the type is followed by - required -, it is a required field

name <string> -required-

Create Pod by defining manifest file

apiVersion: v1
kind: Pod
metadata:
 name: pod-demo
 namespace: default
 labels:
  app: myapp
spec:
 containers:
- name: myapp-1
image: hub.atguigu.com/library/myapp:v1
- name: busybox-1
  image: busybox:latest
  command:
  - "/bin/sh"
  - "-c"
  - "sleep 3600"

kubectl get pod xx.xx.xx -o yaml
<!--use -o Parameter plus yaml，You can configure resources to yaml It can also be used json，Output as json grid