[root@master pod]# kubectl get pods --show-labels

NAME          READY   STATUS             RESTARTS   AGE   LABELS

cv-podh       1/2     CrashLoopBackOff   15         55m   app=myapp,tier=frontend

mysql-gh9ds   1/1     Running            4          28h   app=mysql,cx=z

pod           1/2     CrashLoopBackOff   70         27h   app=myapp,tier=frontend

[root@master pod]# kubectl  label pods mysql-gh9ds sql=3306

pod/mysql-gh9ds labeled

[root@master pod]# kubectl  get pods -l sql=3306 --show-labels

NAME          READY   STATUS    RESTARTS   AGE   LABELS

mysql-gh9ds   1/1     Running   4          28h   app=mysql,cx=z,sql=3306

[root@master pod]# kubectl label pods mysql-gh9ds --overwrite sql=321

pod/mysql-gh9ds labeled

[root@master pod]# kubectl get pods --show-labels -l sql=321

NAME          READY   STATUS    RESTARTS   AGE   LABELS

mysql-gh9ds   1/1     Running   4          28h   app=mysql,cx=z,sql=321

[root@master ~]# kubectl label nodes node01 hg=192.167.10.20

node/node01 labeled

[root@master ~]# kubectl get  nodes --show-labels -l hg

NAME     STATUS   ROLES    AGE   VERSION   LABELS

node01   Ready    <none>   23d   v1.17.0   01=192.168.10.21,beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,hg=192.167.10.20,kubernetes.io

/arch=amd64,kubernetes.io/hostname=node01,kubernetes.io/os=linux

[root@master ~]# kubectl label nodes node01 --overwrite hg=192.167.10.2

node/node01 labeled

 nodeName	<string>   节点名称

nodeSelector	<map[string]string>  通过标签选择  key v集合

apiVersion: v1

kind: ReplicationController

metadata:

  name: mysql

spec:

  replicas: 1

  selector:

    app: mysql

  template:

     metadata:

       labels:

         app: mysql

     spec:

       containers:

       - name: mysql

         image: mysql

         ports:

         - containerPort: 3306

         env:

         - name: MYSQL_ROOT_PASSWORD

           value: "123456"

       nodeSelector:

         cx: ssd

kubectl label nodes node01 cx=ssd

[root@master pod]# kubectl create -f s.yaml

replicationcontroller/mysql created

[root@master pod]# kubectl get pods

NAME          READY   STATUS             RESTARTS   AGE

cv-podh       1/2     CrashLoopBackOff   51         26h

mysql-dswc4   1/1     Running            0          17s

pod           1/2     CrashLoopBackOff   106        2d4h

[root@master pod]# kubectl describe mysql-dswc4

error: the server doesn't have a resource type "mysql-dswc4"

[root@master pod]# kubectl describe pods mysql-dswc4

Name:         mysql-dswc4

Namespace:    default

Priority:     0

Node:         node01/192.168.10.21

Start Time:   Mon, 20 Jan 2020 16:19:10 +0800

Labels:       app=mysql

Annotations:  <none>

Status:       Running

IP:           10.244.1.14

IPs:

  IP:           10.244.1.14

Controlled By:  ReplicationController/mysql

Containers:

  mysql:

    Container ID:   docker://b9bdd898c1bbc3bd5afe10f44cf3c2846242e308973040958f57a2c87da6bde2

    Image:          mysql

    Image ID:       docker-pullable://mysql@sha256:f1df505c4c6e8eae599a0482e3bde3e761cd700c00cbc371a8161648a26817c0

    Port:           3306/TCP

    Host Port:      0/TCP

    State:          Running

      Started:      Mon, 20 Jan 2020 16:19:15 +0800

    Ready:          True

    Restart Count:  0

    Environment:

      MYSQL_ROOT_PASSWORD:  123456

    Mounts:

      /var/run/secrets/kubernetes.io/serviceaccount from default-token-5wzsb (ro)

Conditions:

  Type              Status

  Initialized       True

  Ready             True

  ContainersReady   True

  PodScheduled      True

Volumes:

  default-token-5wzsb:

    Type:        Secret (a volume populated by a Secret)

    SecretName:  default-token-5wzsb

    Optional:    false

QoS Class:       BestEffort

Node-Selectors:  cx=ssd

Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s

                 node.kubernetes.io/unreachable:NoExecute for 300s

Events:

  Type    Reason     Age   From               Message

  ----    ------     ----  ----               -------

  Normal  Scheduled  62s   default-scheduler  Successfully assigned default/mysql-dswc4 to node01

  Normal  Pulling    61s   kubelet, node01    Pulling image "mysql"

  Normal  Pulled     57s   kubelet, node01    Successfully pulled image "mysql"

  Normal  Created    57s   kubelet, node01    Created container mysql

  Normal  Started    57s   kubelet, node01    Started container mysql

[root@master ~]# kubectl  explain pods.metadata

KIND:     Pod

VERSION:  v1

RESOURCE: metadata <Object>

DESCRIPTION:

     Standard object's metadata. More info:

     https://git.k8s.io/community/contributors/devel/sig-architecture/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>   资源注解

     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/sig-architecture/api-conventions.md#metadata

   deletionGracePeriodSeconds	<integer>

     Number of seconds allowed for this object to gracefully terminate before it

     will be removed from the system. Only set when deletionTimestamp is also

     set. May only be shortened. Read-only.

   deletionTimestamp	<string>

     DeletionTimestamp is RFC 3339 date and time at which this resource will be

     deleted. This field is set by the server when a graceful deletion is

     requested by the user, and is not directly settable by a client. The

     resource is expected to be deleted (no longer visible from resource lists,

     and not reachable by name) after the time in this field, once the

     finalizers list is empty. As long as the finalizers list contains items,

     deletion is blocked. Once the deletionTimestamp is set, this value may not

     be unset or be set further into the future, although it may be shortened or

     the resource may be deleted prior to this time. For example, a user may

     request that a pod is deleted in 30 seconds. The Kubelet will react by

     sending a graceful termination signal to the containers in the pod. After

     that 30 seconds, the Kubelet will send a hard termination signal (SIGKILL)

     to the container and after cleanup, remove the pod from the API. In the

     presence of network partitions, this object may still exist after this

     timestamp, until an administrator or automated process can determine the

     resource is fully terminated. If not set, graceful deletion of the object

     has not been requested. Populated by the system when a graceful deletion is

     requested. Read-only. More info:

     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata

   finalizers	<[]string>

     Must be empty before the object is deleted from the registry. Each entry is

     an identifier for the responsible component that will remove the entry from

     the list. If the deletionTimestamp of the object is non-nil, entries in

     this list can only be removed. Finalizers may be processed and removed in

     any order. Order is NOT enforced because it introduces significant risk of

     stuck finalizers. finalizers is a shared field, any actor with permission

     can reorder it. If the finalizer list is processed in order, then this can

     lead to a situation in which the component responsible for the first

     finalizer in the list is waiting for a signal (field value, external

     system, or other) produced by a component responsible for a finalizer later

     in the list, resulting in a deadlock. Without enforced ordering finalizers

     are free to order amongst themselves and are not vulnerable to ordering

     changes in the list.

   generateName	<string>

     GenerateName is an optional prefix, used by the server, to generate a

     unique name ONLY IF the Name field has not been provided. If this field is

     used, the name returned to the client will be different than the name

     passed. This value will also be combined with a unique suffix. The provided

     value has the same validation rules as the Name field, and may be truncated

     by the length of the suffix required to make the value unique on the

     server. If this field is specified and the generated name exists, the

     server will NOT return a 409 - instead, it will either return 201 Created

     or 500 with Reason ServerTimeout indicating a unique name could not be

     found in the time allotted, and the client should retry (optionally after

     the time indicated in the Retry-After header). Applied only if Name is not

     specified. More info:

     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#idempotency

   generation	<integer>

     A sequence number representing a specific generation of the desired state.

     Populated by the system. Read-only.

   labels	<map[string]string>

     Map of string keys and values that can be used to organize and categorize

     (scope and select) objects. May match selectors of replication controllers

     and services. More info: http://kubernetes.io/docs/user-guide/labels

   managedFields	<[]Object>

     ManagedFields maps workflow-id and version to the set of fields that are

     managed by that workflow. This is mostly for internal housekeeping, and

     users typically shouldn't need to set or understand this field. A workflow

     can be the user's name, a controller's name, or the name of a specific

     apply path like "ci-cd". The set of fields is always in the version that

     the workflow used when modifying the object.

   name	<string>

     Name must be unique within a namespace. Is required when creating

     resources, although some resources may allow a client to request the

     generation of an appropriate name automatically. Name is primarily intended

     for creation idempotence and configuration definition. Cannot be updated.

     More info: http://kubernetes.io/docs/user-guide/identifiers#names

   namespace	<string>

     Namespace defines the space within each name must be unique. An empty

     namespace is equivalent to the "default" namespace, but "default" is the

     canonical representation. Not all objects are required to be scoped to a

     namespace - the value of this field for those objects will be empty. Must

     be a DNS_LABEL. Cannot be updated. More info:

     http://kubernetes.io/docs/user-guide/namespaces

   ownerReferences	<[]Object>

     List of objects depended by this object. If ALL objects in the list have

     been deleted, this object will be garbage collected. If this object is

     managed by a controller, then an entry in this list will point to this

     controller, with the controller field set to true. There cannot be more

     than one managing controller.

   resourceVersion	<string>

     An opaque value that represents the internal version of this object that

     can be used by clients to determine when objects have changed. May be used

     for optimistic concurrency, change detection, and the watch operation on a

     resource or set of resources. Clients must treat these values as opaque and

     passed unmodified back to the server. They may only be valid for a

     particular resource or set of resources. Populated by the system.

     Read-only. Value must be treated as opaque by clients and . More info:

     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#concurrency-control-and-consistency

   selfLink	<string>

     SelfLink is a URL representing this object. Populated by the system.

     Read-only. DEPRECATED Kubernetes will stop propagating this field in 1.2

     release and the field is planned to be removed in 1.21 release.

   uid	<string>

     UID is the unique in time and space value for this object. It is typically

     generated by the server on successful creation of a resource and is not

     allowed to change on PUT operations. Populated by the system. Read-only.

     More info: http://kubernetes.io/docs/user-guide/identifiers#uids

Pending:调度不成功；一般调度条件不满足，pod挂起

Running:处于运行状态

Failed：失败

Succeeded:成功

Unknown：未知状态