Shulou(Shulou.com)06/03 Report--

"in-depth analysis of the Kubernetes-12 pilot: my first containerized application"

It mainly includes two steps: making an image and writing a yaml configuration file (or json)

Take deployment of nginx as an example

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

The kind field declares types, such as deployment, daemonset, etc., and metadata is a specific description, such as name, namespace, labels, annotations, etc.

Spec.template describes the details of pod, that is, the template for container configuration

Create deployment

$kubectl create-f nginx-deployment.yaml

View the operation of deployment

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

View API object details

Kubectl describe pod nginx-deployment-67594d6bf6-9gdvrName: nginx-deployment-67594d6bf6-9gdvrNamespace: defaultPriority: 0PriorityClassName: Node: node-1/10.168.0.3Start Time: Thu 16 Aug 2018 08:48:42 + 0000Labels: app=nginx pod-template-hash=2315082692Annotations: Status: RunningIP: 10.32.0.23Controlled 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

The Events field can be used to locate later problems, and the common ones are

(1) unable to find a suitable node node scheduling pod, including

Node node label mismatch

Insufficient allocation of node node resources

The node node is blemished

Node node network exception

(2) failed to pull image

Upgrade container image version

... Spec: containers:-name: nginx image: nginx:1.8 # here has been modified from 1.7.9 to 1.8 ports:-containerPort: 80

Execution

$kubectl replace-f nginx-deployment.yaml

A more common way is to perform relevant operations through apply, which can be created or modified through this command

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

Here is an example of a volume mount

It is usually divided into emptyDir and hostPath. The difference between the two is that the former does not need to specify a host directory (source directory), while K8s creates a temporary directory on the host and mounts it, while the latter needs to explicitly declare the mounted source directory, such as mounting the host's / usr/local/nginx/html directory to the same location of the container

The example of emptyDir

An example of volumes:-name: nginx-vol emptyDir: {} hostPath. Volumes:-name: nginx-vol hostPath: path: / var/data

Enter the container

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

Delete Container

$kubectl delete-f nginx-deployment.yaml

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