Four, k8s resource cluster definition entry list

Resource object

1. workload：Pod， ReplicaSet， Deployment， StatefulSet， DaemonSet， Job， Cronjob
2. Service Discovery and balanced: Service, Ingress
3. Configuration and storage: Volume, CSI, ConfigMap, Secret, DownwardAPI
4. Cluster-level resources: Namespace, Node, Role, ClusterRole, RoleBinding, ClusterRoleBinding
5. Metadata type resources: HPA, PodTemplate, LimitRange

Ways to create resources

apiserver: only accepts resource definition in JSON format;

Provide configuration list using yaml format, apiserver can be automatically converted to JSON format, and then execution;

Most resource configuration list:

1. apiVersion: group/version

$ kubectl api-versions

1. kind resource category (pod, service, deployment, etc.)
2. metadata: Metadata

nameUnder the same namespace name must be unique
namespacenamespace
labelslabels, each label resource can have
annotations resource comment

3.spec: user desired target state, disired state

4.status: current status, should be infinitely close to spec state, current state, this field is maintained by kubernetes cluster; users can not customize;

Help command list

Can kubectl explainhelp to see the list of required

Such as:

[root@master ~]# kubectl explain pod
KIND:     Pod
VERSION:  v1

DESCRIPTION:
     Pod is a collection of containers that can run on a host. This resource is
     created by clients and scheduled onto hosts.

FIELDS:
   apiVersion   <string>
     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

   kind <string>
     Kind is a string value representing the REST resource this object
     represents. Servers may infer this from the endpoint the client submits
     requests to. Cannot be updated. In CamelCase. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds

   metadata <Object>（ 元数据 ）
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata

   spec <Object>  （用户定义的所希望的目标状态==最重要的字段）
     Specification of the desired behavior of the pod. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status

   status   <Object>（k8s集群当前所处状态，应无限向目标状态靠拢，只读的，不受人为控制）
     Most recently observed status of the pod. This data may not be up to date.
     Populated by the system. Read-only. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#spec-and-status

See here is the first layer pod, such as the information == metadata == want, continue to view directly pod.metadata

Such as:

[root@master ~]# kubectl explain pod.metadata
KIND:     Pod
VERSION:  v1

RESOURCE: metadata <Object>

DESCRIPTION:
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata

     ObjectMeta is metadata that all persisted resources must have, which
     includes all objects users must create.

FIELDS:
   annotations  <map[string]string>
     Annotations is an unstructured key value map stored with a resource that
     may be set by external tools to store and retrieve arbitrary metadata. They
     are not queryable and should be preserved when modifying objects. More
     info: http://kubernetes.io/docs/user-guide/annotations

   clusterName  <string>
     The name of the cluster which the object belongs to. This is used to
     distinguish resources with same name and namespace in different clusters.
     This field is not set anywhere right now and apiserver is going to ignore
     it if set in create or update request.

   creationTimestamp    <string>
     CreationTimestamp is a timestamp representing the server time when this
     object was created. It is not guaranteed to be set in happens-before order
     across separate operations. Clients may not set this value. It is
     represented in RFC3339 form and is in UTC. Populated by the system.
     Read-only. Null for lists. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata
     .......
     .......
     # 太多就不复制了

So is the case;

• kubectl explain pod.spec
• kubectl explain pod.status

Category:
there will be a corresponding field in each, after they,

Types of	Explanation	For example
string	String	String
[]string	List of strings	You need to fill an array of type String
map[string]string	View string	There are many needs k: v type of data
Object	Objects	DESCRIPTION need a lower field nested
[]Object	Object List	A plurality of instructions can be nested at a required field
- required -	Required	When this occurs when this parameter must be filled

Create a test list

Create a pod-demo.yamlfile, reads as follows:

• Precautions
  • Note case
  • List need to add "-" generally use the same level

[root@master manifests]# cat pod-demo.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod-demo
  namespace: default
  labels:
    app: myapp
    tier: frontend
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
  - name: busybox
    image: busybox:latest
    command: 
    - "/bin/sh"
    - "-c"
    - "sleep 3600"

Use kubectl createthe command to load the file operations

[root@master manifests]# kubectl create -f pod-demo.yaml 
pod/pod-demo created
[root@master manifests]# kubectl get pods -o wide
NAME                            READY   STATUS    RESTARTS   AGE     IP           NODE                NOMINATED NODE   READINESS GATES
pod-demo                        2/2     Running   0          20s     10.244.3.8   node01.kubernetes   <none>           <none>

We can see already properly started.

If you want to delete this pod, is used kubectl deleteto to pod-demo.yamloperate may be;

[root@master manifests]# kubectl delete -f pod-demo.yaml 
pod "pod-demo" deleted

How resources are three ways to create

For kubernetesresources, there are three ways to create

1. The first is the last article, and use the command to create

2, the second is demonstrated in this article, configuration list style usage. Also known as command-list resources

3, the third is declarative resource list, a third way that is similar to the second list.

Declarative is to ensure that the resources we declare a state of change as much as possible, and we are ready to change our statement and application at any time.