pod的状态及操作

查看pod的标签

[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

给pod添加标签

[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

修改pod标签

[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

给节点打标签

[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

　　给节点修改标签

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

　　pod 节点标签选择器

 nodeName	<string>   节点名称

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

　 示例

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

　　资源注解annotations;仅用于为对象提供元数据

[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

　　pod 的生命周期状态

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

　　pod 创建流程经历那些阶段

请求提交给apisaerver -->apiserver先把它保存在etcd当中--->aipserver会请求Schedule负责调度如果调度成功并把调度结果存放etcd当中---->目标节点的kubelet，通过maseter上的apiserver就会知道有一个新任务给自己---kubelet就会拿到用户期望创建pod的清单，并跟根据清单运行起pod，无论创建成功或失败都会把状态发送给apiserver

pod里容器探测

liveness：容器是否存活，因为pod可以有多个容器，一个容器挂了，另一个容器没挂，pod正常

readiness：容器里的服务是否可以正常提供服务

pod里容器重启策略