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Kubernetes (K8s) has become the backbone of modern container orchestration, enabling organizations to deploy, scale, and manage containerized applications with ease. However, mastering Kubernetes requires more than just running kubectl commands you need a solid grasp of its architecture, components, and operational principles.
Whether you’re preparing for a certification, an interview, or simply want to gauge your Kubernetes expertise, this post presents 10 essential questions to challenge your understanding. These questions cover key areas such as Pods, Deployments, Services, Networking, and more.
Are you ready to test your Kubernetes knowledge? Let’s dive in!
1 – How would you troubleshoot if in a Pod repeatedly exits and restarts ?
well, if a pod repeatedly crashes, kubectl exec is not he best choise, instead verify node and container logs, inspect pod status, and try to use kubectl debug to start a temporay container for investigating in the environment and dependencies.
2 – How can an application scale to handle traffic fluctuations?
One of the main Functionalities the came with Kubernetes are the Horizontal Pod Autoscaling (HPA) and Vertical Pod Autoscaling (VPA). VPA involves recreating Pods with adjusted resources, limiting its scenarios. HPA is more commonly used, dynamically adjusting Pod counts based on metrics like CPU usage, request rate, or custom metrics.
3 – Your livenessProbe Works, but Is Your App Really Healthy ?
From an application perspective, a livenessProbe only verifies if the application is running, but it doesn’t assess its functionality. The application could be in a degraded state or have errors in certain functions or classes that aren’t accessed by the probe, yet it would still pass.
From a network perspective, a livenessProbe (e.g., httpGet) sends requests from the node’s kubelet, which only confirms local availability—it does not ensure cross-node network reliability.
4 – How should application logs be collected, and is there a risk of losing logs?
Logs can be sent to stdout/stderr or written to files. When using stdout/stderr, logs are stored on the node and can be collected by log agents like Fluentd or Filebeat, typically running as a DaemonSet. However, if a Pod is deleted before the agent retrieves its logs, they may be lost. To prevent this, writing logs to files on persistent storage ensures data retention even if the Pod is removed.
5 – Is a Pod stable once created, even if the user takes no further action?
The answer is definitely no. A Pod is not stable once created, even if the user takes no further action. and here’s why:
- Pods Are Ephemeral : Kubernetes treats Pods as disposable units. If a node fails or a Pod crashes, Kubernetes may restart or reschedule it elsewhere, depending on the configuration.
- Lack of Self-Healing : A standalone Pod without a controller (like a Deployment or StatefulSet) won’t be automatically recreated if it fails.
- Resource Constraints : If a Pod exceeds CPU or memory limits, the scheduler may evict or throttle it, impacting stability.
- Node Failures & Rescheduling : If the node hosting the Pod becomes unavailable, the Pod will go down unless managed by a higher-level controller.
- Network & Dependency Issues : A Pod may start successfully but fail due to missing dependencies, network failures, or service disruptions.
To ensure stability, Pods should be managed using Deployments, StatefulSets, or other controllers that provide self-healing and scaling capabilities.
6 – Can application configurations, such as environment variables or ConfigMap updates, be applied dynamically to a running Pod without requiring a restart?
Whether configuration updates apply dynamically depends on how they are used. Changes to environment variables do not take effect dynamically; if a ConfigMap or Secret is updated and referenced as an environment variable, the Pod must be restarted.
However, when a ConfigMap or Secret is mounted as a volume, Kubernetes automatically updates the files. In this case, the application must detect and reload the changes for them to take effect without requiring a Pod restart.
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Kubernetes is a powerful yet complex system, and mastering it requires more than just running commandsit demands a deep understanding of its architecture, behavior, and best practices. From troubleshooting crashing Pods to managing configuration updates, ensuring log persistence, and scaling applications effectively, these fundamental questions highlight key areas every Kubernetes user should grasp.
By continuously testing your knowledge and staying informed about best practices, you can enhance your ability to deploy and maintain resilient, scalable, and efficient Kubernetes environments. Keep exploring, experimenting, and refining your skills—because in the world of Kubernetes, there’s always more to learn! 🚀
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