[12] study notes a small chopper pilot: My first container application

"In-depth analysis Kubernetes - 12 small chopper pilot: My first container applications."

Includes two steps: the preparation and production of image yaml profile (or json)

Nginx as an example to the deployment

apiVersion: apps/v1 
kind: Deployment 
metadata: 
  name: nginx-deployment 
spec: 
  selector: 
    matchLabels: 
      app: nginx 
  replicas: 2 
 template: 
   metadata: labels: 
     app: nginx 
   spec: 
     containers: 
     - name: nginx 
       image: nginx:1.7.9 
       ports: 
       - containerPort: 80

Wherein the kind field declared type, e.g. deployment, daemonset the like, Metadata is specifically described, for example, name, namespace, labels, annotations, etc.

spec.template describes the details of the pod, i.e., container configuration template

Creating deployment

$ kubectl create -f nginx-deployment.yaml

View deployment operation

$ kubectl get pods -l app=nginx 
NAME READY STATUS RESTARTS AGE n
ginx-deployment-67594d6bf6-9gdvr 1/1 Running 0 10m 
nginx-deployment-67594d6bf6-v6j7w 1/1 Running 0 10m

View details of API objects

kubectl describe pod nginx-deployment-67594d6bf6-9gdvr
Name:               nginx-deployment-67594d6bf6-9gdvr
Namespace:          default
Priority:           0
PriorityClassName:  <none>
Node:               node-1/10.168.0.3
Start Time:         Thu, 16 Aug 2018 08:48:42 +0000
Labels:             app=nginx
                    pod-template-hash=2315082692
Annotations:        <none>
Status:             Running
IP:                 10.32.0.23
Controlled By:      ReplicaSet/nginx-deployment-67594d6bf6
...
Events:

  Type     Reason                  Age                From               Message

  ----     ------                  ----               ----               -------
  
  Normal   Scheduled               1m                 default-scheduler  Successfully assigned default/nginx-deployment-67594d6bf6-9gdvr to node-1
  Normal   Pulling                 25s                kubelet, node-1    pulling image "nginx:1.7.9"
  Normal   Pulled                  17s                kubelet, node-1    Successfully pulled image "nginx:1.7.9"
  Normal   Created                 17s                kubelet, node-1    Created container
  Normal   Started                 17s                kubelet, node-1    Started container

Events which have late field can be used to locate the problem, common

(1) find a suitable node node schedules pod, comprising

match node is not the node label;

node node resources are not enough;

node node has the stain;

abnormal nodes in the network node;

(2) pull the mirror fails

Container mirrored version upgrade

...     
    spec: 
      Containers: 
      - name: nginx 
        Image: nginx: # 1.8 here is modified from 1.7.9 to 1.8 
        the ports: 
      - containerPort: 80

carried out

$ kubectl replace -f nginx-deployment.yaml

The more common way is to apply through the implementation of related operations, whether it is created or modified can be done through the command

$ Kubectl apply -f nginx-deployment.yaml  
# nginx-deployment.yaml modify the content of  
$ kubectl apply -f nginx-deployment.yaml

The following is an example of a mounted volume

EmptyDir and is usually divided into two kinds hostPath, the difference is that the former does not need to specify the host directory (source directory), K8S creates a temporary directory on the host and mount it; and the latter is linked to the need to explicitly declare contained in the source directory, for example, host computer / usr / local / nginx / html directory is mounted to the same position of the container

emptyDir examples

volumes:
      - name: nginx-vol
        emptyDir: {}
hostPath的例子
...   
    volumes:
      - name: nginx-vol
        hostPath: 
          path: /var/data

Into the container

$ kubectl exec -it nginx-deployment-5c678cfb6d-lg9lw -- /bin/bash 
# ls /usr/share/nginx/html

Delete container

$ Kubectl delete -F nginx deployment.yaml