This documentation is about investigating and diagnosing kubectl related issues. If you encounter issues accessing kubectl or connecting to your cluster, this document outlines various common scenarios and potential solutions to help identify and address the likely cause. Before you begin You need to have a Kubernetes cluster. You also need to have kubectl installed - see install tools Verify kubectl setup Make sure you have installed and configured kubectl correctly on your local machine.

FEATURE STATE: Kubernetes v1.21 [stable] This page shows how to limit the number of concurrent disruptions that your application experiences, allowing for higher availability while permitting the cluster administrator to manage the clusters nodes. Before you begin Your Kubernetes server must be at or later than version v1.21. To check the version, enter kubectl version. You are the owner of an application running on a Kubernetes cluster that requires high availability.

To scale an application and provide a reliable service, you need to understand how the application behaves when it is deployed. You can examine application performance in a Kubernetes cluster by examining the containers, pods, services, and the characteristics of the overall cluster. Kubernetes provides detailed information about an application's resource usage at each of these levels. This information allows you to evaluate your application's performance and where bottlenecks can be removed to improve overall performance.

This page shows how to define dependent environment variables for a container in a Kubernetes Pod. Before you begin You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

This page shows how a Pod can use environment variables to expose information about itself to containers running in the Pod, using the downward API. You can use environment variables to expose Pod fields, container fields, or both. In Kubernetes, there are two ways to expose Pod and container fields to a running container: Environment variables, as explained in this task Volume files Together, these two ways of exposing Pod and container fields are called the downward API.

In this example, you will run a Kubernetes Job with multiple parallel worker processes. In this example, as each pod is created, it picks up one unit of work from a task queue, completes it, deletes it from the queue, and exits. Here is an overview of the steps in this example: Start a message queue service. In this example, you use RabbitMQ, but you could use another one. In practice you would set up a message queue service once and reuse it for many jobs.

FEATURE STATE: Kubernetes v1.34 [beta] This page provides an overview of MutatingAdmissionPolicies. MutatingAdmissionPolicies allow you change what happens when someone writes a change to the Kubernetes API. If you want to use declarative policies just to prevent a particular kind of change to resources (for example: protecting platform namespaces from deletion), ValidatingAdmissionPolicy is a simpler and more effective alternative. To use the feature, enable the MutatingAdmissionPolicy feature gate (which is off by default) and set --runtime-config=admissionregistration.

This document details the deprecation policy for various facets of the system. Kubernetes is a large system with many components and many contributors. As with any such software, the feature set naturally evolves over time, and sometimes a feature may need to be removed. This could include an API, a flag, or even an entire feature. To avoid breaking existing users, Kubernetes follows a deprecation policy for aspects of the system that are slated to be removed.

This section is relevant for people adopting a new built-in sidecar containers feature for their workloads. Sidecar container is not a new concept as posted in the blog post. Kubernetes allows running multiple containers in a Pod to implement this concept. However, running a sidecar container as a regular container has a lot of limitations being fixed with the new built-in sidecar containers support. FEATURE STATE: Kubernetes v1.33 [stable] (enabled by default: true) Objectives Understand the need for sidecar containers Be able to troubleshoot issues with the sidecar containers Understand options to universally "inject" sidecar containers to any workload Before you begin You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster.

Objectives Perform a rolling update using kubectl. Updating an application Rolling updates allow Deployments' update to take place with zero downtime by incrementally updating Pods instances with new ones. Users expect applications to be available all the time, and developers are expected to deploy new versions of them several times a day. In Kubernetes this is done with rolling updates. A rolling update allows a Deployment update to take place with zero downtime.