How to write yaml file in a standard way

1、Yaml grammar

      1.1  Use white space and indentation to represent hierarchy （ It's kind of similar Python）, Curly braces and square brackets can be omitted .

      1.2 have access to # Write notes , Compared with JSON It's a big improvement .

      1.3 object （ Dictionaries ） The format and JSON Basically the same , but Key You don't need to use double quotes , Use {a,b,c}.

      1.4 Array （ list ） It's using - List form at the beginning , Use [a,b,c].

      1.5 Representing the object : And representing an array - There must be a space after it . have access to --- Separate multiple in one file YAML object .

2、Ymal Illustrate with examples

       2.1 Array example

# YAML Array ( list )
OS:
  - linux
  - macOS
  - Windows

--------------------------
#josn Array 

{
  "OS": ["linux", "macOS", "Windows"]
}

        2.2  YAML object （ Dictionaries ）

# YAML object ( Dictionaries )
Kubernetes:
  master: 1
  worker: 3

----------------------
#json  object 
{
  "Kubernetes": {
    "master": 1,
    "worker": 3
  }
}

        2.3 Yaml Array Object combination example

# Yaml  Array   Object combination 
Kubernetes:
  master:
    - apiserver: running
    - etcd: running
  node:
    - kubelet: running
    - kube-proxy: down
    - container-runtime: [docker, containerd, cri-o]

 3、Yaml Format specification  

apiVersion: v1  #API Version number , Because different versions are different , So we need to distinguish versions .
kind: Pod       # The type of resource object , Yes pod,Node,Job,Service
metadata:       # Meta information , Mark the object , Easy to manage 
  name: ngx-pod #pod give a name 
  labels:       # to pod tagging , Easy to find 
    env: demo
    owner: feifei

spec:           #POD Information about the content container 
  containers:   # Containers 
  - image: nginx:alpine    # Run container image 
    name: ngx              # Container name 
    ports:                 # Port number 
    - containerPort: 80    # Declare container port number 

        3.1 yaml File creation and deletion

kubectl apply -f ngx-pod.yml
kubectl delete -f ngx-pod.yml

4、 To write yaml skill

        4.1 First skill first Official documents

        4.2 The second technique uses Kubectl api-resources command , Displays the corresponding API Version and type , for example pods The version is v1 runtimeclasses The version is node.k8s.io/v1

[email protected]:~$ kubectl  api-resources
NAME                              SHORTNAMES   APIVERSION                             NAMESPACED   KIND
bindings                                       v1                                     true         Binding
componentstatuses                 cs           v1                                     false        ComponentStatus
configmaps                        cm           v1                                     true         ConfigMap
endpoints                         ep           v1                                     true         Endpoints
events                            ev           v1                                     true         Event
limitranges                       limits       v1                                     true         LimitRange
namespaces                        ns           v1                                     false        Namespace
nodes                             no           v1                                     false        Node
persistentvolumeclaims            pvc          v1                                     true         PersistentVolumeClaim
persistentvolumes                 pv           v1                                     false        PersistentVolume
pods                              po           v1                                     true         Pod
podtemplates                                   v1                                     true         PodTemplate
replicationcontrollers            rc           v1                                     true         ReplicationController
resourcequotas                    quota        v1                                     true         ResourceQuota
secrets                                        v1                                     true         Secret
serviceaccounts                   sa           v1                                     true         ServiceAccount
services                          svc          v1                                     true         Service
runtimeclasses                                 node.k8s.io/v1                         false        Runtime

        4.3  The third skill is to use commands kubectl explain, It's quite so Kubernetes-api Help document , Will make a detailed description of the target object . Particular attention . Dot notation , for example kuebectl explain pod.spec.volumes, A point represents a target object , The more points , The deeper the hierarchy .

[email protected]:~$ kubectl explain pod.spec.volumes.vsphereVolume
KIND:     Pod
VERSION:  v1

RESOURCE: vsphereVolume <Object>

DESCRIPTION:
     VsphereVolume represents a vSphere volume attached and mounted on kubelets
     host machine

     Represents a vSphere volume resource.

FIELDS:
   fsType	<string>
     Filesystem type to mount. Must be a filesystem type supported by the host
     operating system. Ex. "ext4", "xfs", "ntfs". Implicitly inferred to be
     "ext4" if unspecified.

   storagePolicyID	<string>
     Storage Policy Based Management (SPBM) profile ID associated with the
     StoragePolicyName.

   storagePolicyName	<string>
     Storage Policy Based Management (SPBM) profile name.

   volumePath	<string> -required-
     Path that identifies vSphere volume vmdk

        4.4 The fourth technique , Give Way kubectl Directly generate a template for us , Namely kubectl Two special parameters of --dry-run=client and -o yaml, The former is empty , The latter is generation yaml Format , Combined use will make kubectl There will be no actual creation action , And only generate yaml file .

# Generate pod Of yaml Sample template , Can be in kubectl run  Add these two parameters later 
--dry-run=client -o yaml  Then redirect to a directory , It can't be under the root directory 

kubectl run ngx --image=nginx:alpine --dry-run=client -o yaml > /tmp/pod.yaml

     

kubectl run ngx --image=nginx:alpine --dry-run=client -o yaml >/tmp/pod.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: ngx
  name: ngx
spec:
  containers:
  - image: nginx:alpine
    name: ngx
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

        4.5 And then on the generated yaml File for editing , Make sure to generate , Or delete

        4.6 Can also be kubectl Two parameters of alias Define it , Generating variables

export do="--dry-run=client -o yaml"
kubectl run ngx --image=nginx:alpine $do