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This article mainly introduces how to view the Pods and nodes, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

Kubernetes Pods

When you create the deployment, Kubernetes creates a Pod to host the application instance. Pod is an Kubernetes abstraction that represents a combination of one or more application containers, such as Docker or rkt, and some shared resources for those containers. These resources include:

Shared storage, such as volumes

Network, as the only cluster IP address

Information about how to run each container, such as the container image version or the specific port to use

Pod models application-specific "logical hosts" and can contain different application containers that are relatively tightly coupled. For example, Pod might include both containers with Nodejs applications and containers that provide data published by the Nodejs web server. Containers in Pod share an IP address and port space, which are always on the same node and running in the same context.

Pods is an atomic unit on the Kubernetes platform. When we create a deployment on Kubernetes, the deployment will create a Pods containing the container (instead of creating the container directly). Each Pod is bound to the node where the debug executes it and remains until terminated (according to the restart policy) or deleted. In the case of node failure, the same pod is scheduled on other available nodes in the cluster.

Overview of Pod

Nodes

Pod always runs on the node. A node is a working machine in Kubernetes, which can be either a virtual machine or a physical machine, depending on the cluster. Each node is managed by the primary node. A node can have multiple pod, and Kubernetes master automatically handles pod scheduling between nodes in the cluster. The automatic scheduling of the primary node takes into account the resources available on each node.

At least the services that each Kubernetes node is running:

Kubelet, which is responsible for the communication process between Kubernetes Master and Node; it manages the pod and containers running on the machine.

The container runtime (such as Docker, rkt) is responsible for extracting the container image from the registry, extracting the container, and running the application.

Overview of nod

Troubleshooting with kubectl

The Kubectl command tool can obtain information about deployed applications and their environments. The most common operations can be done using the following kubectl command:

Kubectl get-column resources

Kubectl describe-displays detailed information about resources

Kubectl logs-print logs from a pod container

Kubectl exec-execute commands on containers in pod

You can use these commands to view the deployment time, current status, running location, and configuration of the application.

Practice environment: https://kubernetes.io/docs/tutorials/kubernetes-basics/explore/explore-interactive/

Check the application configuration

We will use the kubectl get command and find the existing Pods: kubectl get pods

You will see the result as shown in the figure:

Next, to view the containers in Pod and the images used to build them, we run the describe pods command: kubectl describe pods

You will see the result as shown in the figure:

Display app on the terminal

Pods runs in an isolated private network-- so we need agents to access them in order to debug and interact with them. To do this, we will use the kubectl proxy command to run the agent in the second terminal window: kubectl proxy

Now we will get the Pod name again and query the Pod directly through the agent. Get the Pod name and store it in the POD_NAME environment variable: export POD_NAME=$ (kubectl get pods-o go-template-- template'{{range. Items}} {{metadata.name}} {{"\ n"}} {{"\ n"}} {{end}'); echo "Name of the Pod: $POD_NAME"

To view the output of the application, run the curl request: curl http://localhost:8001/api/v1/namespaces/default/pods/$POD_NAME/proxy/

View container log

Anything an application typically sends to STDOUT becomes a log of a container in Pod. We can retrieve these logs using the kubectl logs command: kubectl logs $POD_NAME

Thank you for reading this article carefully. I hope the article "how to View Pods and nodes" shared by the editor will be helpful to you. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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