Kubernetes
Kubernetes Certification Practice Test 2023

Kubernetes is an open-source platform for managing containerized workloads and services that provides both declarative and automated configuration.

Navigate to your AKS cluster via the Azure portal to view the Kubernetes resources. Your resources are accessed through the left-hand navigation pane.

Kubernetes and Docker are two components of the Kubernetes ecosystem. Kubernetes is in charge of cluster health, while Docker is in charge of application containers.

Kubernetes is an open-source platform for managing containerized workloads and services that allows both declarative and automated setup. It has a vast and constantly expanding ecosystem. Service, support, and tools for Kubernetes are widely available.

Kubernetes is an open source distributed system that abstracts the underlying physical infrastructure to make containerized applications easier to execute at scale. A Kubernetes-managed application is made up of containers that have been grouped together and coordinated into a single entity.

A Kubernetes pod is the smallest unit of a Kubernetes application, consisting of one or more Linux containers. A pod can be made up of many, tightly coupled containers (a more complex use case) or just a single container (a simpler use case) (a more common use case).

A Kubernetes cluster is a collection of node machines used to run containerized apps. You’re running a cluster if you’re using Kubernetes. A cluster must have a control plane and one or more compute devices, or nodes, at the very least.

Kubernetes administrator command-line tool, kubectl, can be used to create a secret. This program allows you to utilize files or literal strings from your local workstation, package them into secrets, and use an API to construct objects on the cluster server. Secret objects must take the form of a DNS subdomain name.

Kubernetes can be used on-premises, in the cloud, or at the edge. Kubernetes manages clusters of Amazon Elastic Compute Cloud (EC2) instances that host your containers when used in conjunction with AWS.

To get started, you’ll need to set up a Kubernetes cluster. Make sure you’re connected to the Kubernetes cluster by running kubectl get nodes in the command line to see the cluster’s nodes in the terminal once you’ve entered the Kubernetes sandbox environment. You’re now ready to generate and execute a pod if that works.

Kubernetes (K8s) is a container orchestration platform that is open source. It automates all of a container’s manual procedures, such as deployment, scaling, and application management.

A Kubernetes cluster is made up of nodes, or worker machines, that run containerized applications. A worker node is required in every cluster. The Pods, which make up the application workload, are hosted by the worker node (s).

Getting the Cluster IP Address of a Kubernetes Pod On your local system, run the kubectl get pod command with the -o wide option to acquire the cluster IP address of a Kubernetes pod. This option displays additional information, such as the pod’s cluster IP and the node on which the pod is located.

Docker is an open-source platform for automating the deployment of applications into portable, self-contained containers that can run in the cloud or on-premises. Despite having a similar name, Docker, Inc. is one of the firms that develops the open-source Docker technology to run on Linux and Windows in conjunction with cloud providers such as Microsoft. Kubernetes, on the other hand, is open-source orchestration software that provides an API for controlling how and where containers are run. It enables you to execute Docker containers and workloads, as well as assisting you in overcoming some of the operational challenges associated with scaling numerous containers across different servers.

The Container Storage Interface specification, which offers a standardized means for establishing connectivity between container orchestration tools and storage systems, is implemented in Kubernetes CSI.

Kubernetes is referred to as K8s. You can just substitute the ‘ubernete’ with the number 8 instead of the complete word. Finish with an’s’.

Kubernetes is a highly capable container management system. It manages and deploys containers automatically. In cloud computing, it’s the next big thing. Businesses are migrating their infrastructure and architecture to reflect a cloud-native, data-driven world, which is understandable.

Access Logs for Your Application from Kubernetes Pods You can get logs for your application from Kubernetes pods. To get started, open a command-line window. Find the pods that are appropriate for your application.

In Kubernetes, a ReplicaSet is a process that runs several instances of a Pod while keeping the number of Pods constant.

Because Kubernetes is a container orchestrator, it requires a container runtime to function. Although Kubernetes is most often associated with Docker, it may be used with any container runtime. Other container runtimes that you may use with Kubernetes include RunC, cri-o, and containerd.

You don’t need to spend much time studying Kubernetes if you already have some expertise with Linux and the fundamental command-line interface. It’s more about the applications that will aid you in your learning process.

Yes, Kubernetes is a superior container orchestration system. Many developers, DevOps professionals, and businesses prefer it. Furthermore, it is supported by all of the main cloud providers.

Kubernetes is a free and open source program that was created from Google’s Borg code and first released in June 2014.

In Kubernetes, a deployment is the act of giving declarative updates to Pods. The controller will convert the current state to the declared state if the intended state is declared in the manifest (YAML) file.

In the Kubernetes system, Kubernetes objects are persistent things. These entities are used by Kubernetes to reflect the state of your cluster. Pods, Namespaces, StatefulSets, Services, and other Kubernetes Objects are examples.

Helm is a Kubernetes package management that can be used to install and upgrade apps using Helm charts.

Namespaces are a feature of Kubernetes that allows you to isolate groupings of resources within a cluster. Within a namespace, resource names must be unique, but not across them.

Namespaces are a feature of Kubernetes that allows you to isolate groupings of resources within a cluster. Within a namespace, resource names must be unique, but not across them.

What if you wish to run a batch job on a regular basis, such as every two hours? A cron expression can be used to generate a Kubernetes cronjob. The task will begin automatically according to the schedule you specify in the job description.

What if you wish to run a batch job on a regular basis, such as every two hours? A cron expression can be used to generate a Kubernetes cronjob. The task will begin automatically according to the schedule you specify in the job description.

Rolling Restart

Kubernetes now allows you to roll back your deployment with update 1.15. This is the quickest restart method in Kubernetes.

Modern apps are built on top of containers, and Kubernetes provides the framework to run them all.

Calico is a networking and security solution for containers, virtual machines, and native host-based workloads that is open source. Calico supports Kubernetes, OpenShift, Mirantis Kubernetes Engine (MKE), OpenStack, and bare metal services.

Ingress refers to incoming connections to a Kubernetes pod, whereas egress refers to outgoing connections from the pod. In Kubernetes network policy, you can specify separate “allow” rules for ingress and egress (egress, ingress, or both).

Rancher is a Kubernetes cluster management software. Not only does this entail managing existing clusters, but it also entails creating new clusters.

Google created Kubernetes in 2014 as an expandable, portable, and open-source platform. It’s mostly used to automate container-based application deployment, scaling, and operations across a cluster of nodes.

The Cloud Native Computing Foundation now maintains Kubernetes, which was initially developed and designed at Google (CNCF).

Kubernetes is open source, but it is also accessible through IT vendors. It’s a complicated tool that allows for container orchestration at scale.

A Kubernetes Node is a logical grouping of IT resources that manages one or more containers. The services required to execute Pods (Kubernetes’ container units), connect with master components, configure networking, and perform assigned workloads are all found on nodes.

The service will send requests to TargetPort, which your pod will listen on. This port must be open for your container’s application.

In the event that one container fails, another must be started. Kubernetes saves the day in this case! Kubernetes is a platform for running distributed systems that is both scalable and robust. It handles your application’s scaling and failover, as well as provides deployment strategies.

The kubernetes Ingress acts as a proxy between your cluster and the outside world.

Kubernetes Deployment is based on a specification YAML file in which you provide the needed state. The present state of Pods or ReplicaSets is then changed to the required state by the deployment controller. Deployments can be used to build new ReplicaSets, destroy existing ReplicaSets, and perform a variety of additional tasks.

Kubernetes container management relies heavily on load balancing. A load balancer distributes network traffic among different Kubernetes services, allowing you to make better use of your containers and increase service availability.

Containers in the same Pod can communicate with each other using localhost and then the port number exposed by the other container in Kubernetes. The IP address of a container in a Pod can be used to connect to another Pod.

kubectl logs -p terminated pod name> will show you the logs of the previous terminated pod.

You must use the register-cluster API to connect Kubernetes clusters to Amazon EKS and then deploy the manifest to your clusters. This manifest provides the EKS Connector and proxy agent configurations. The proxy agent interacts with Kubernetes to deliver AWS requests, whereas the EKS Connector agent facilitates connectivity to AWS. To connect to AWS services, Amazon EKS uses the AWS Systems Manager agent.

To troubleshoot a Kubernetes deployment, IT teams must start with the fundamentals of troubleshooting and work their way down to the smallest elements in order to uncover the core cause of the issue.

Simply use the kubectl delete secret command to erase a Secret: If a Secret is destroyed while a Secret volume is associated, an error message will appear anytime the volume reference disappears.

Run kubectl remove namespace name> to delete a namespace and all its components. The terminal prints a confirmation message.

To retrieve the access token, type kubectl describe secret dashboard-admin-sa-token-kw7vn into the kubectl describe secret dashboard-admin-sa-token-kw7vn command. Copy the token and paste it into the token box on the Kubernetes dashboard login page.

• Installing and configuring Hyper-V
• Download Docker for Windows and install it.
• Install Kubernetes on Windows 10
• Install Kubernetes Dashboard
• Go to your dashboard.

• Configure the Kubernetes Repository
• Install kubelet, kubeadm, and kubectl
• Configure the Hostname on the Nodes
• Set up the Firewall
• Make sure your Iptables settings are up to date.
• Turn off SELinux
• Turn off SWAP.

To delete the pod, use the terminal command “kubectl delete pod nginx.” Before you run this command, double-check the name of the pod you want to destroy. You’ll see the following result if you press enter after “kubectl delete pod nginx.” This will successfully destroy the pod, with the output ‘pod “nginx” deleted’.

We can list all of the pods, services, statefulsets, and other resources in a namespace using the kubectl get all command, but not all of the resources are presented.

Resource requests and limitations provide a convenient approach to manage Kubernetes resources. You may allocate discrete bits of compute and memory to each container using resource requests and constraints. The quantity of resources sought for a container is referred to as resource requests.

• Create a Dockerfile
• Creating an Image with a Dockerfile
• Check to see if the image has been made and is listed.
• Upload to Docker Hub to share with the rest of the world if desired.
• Begin the container with an image.
• Create a kubernetes manifest file.
• Create and Build a POD from a Manifest File
• Validate and track the POD creation process.
• In Kubernetes DashBoard, look at the freshly formed POD.

The Docker Desktop GUI and the kubectl command line can both be used to change the Context. Right-click on the Docker icon on the taskbar and select the Kubernetes option to change the context using the GUI. Select the Context you want to use from the Context drop-down menu.

After you’ve enrolled, you’ll be assigned a Project to work on. This is where all of your GCP resources are created. Now, go to the terminal menu in the upper left, select Kubernetes Engine, and then Clusters: Create cluster.

A Pod cannot be stopped or paused in Kubernetes. You can, however, delete a Pod if you have the manifest to restore it.

The $kubclt get hpa command can be used to check the status of the autoscaler.

The plan is to upgrade the control node first, then the functioning node after the load and traffic have been removed.

• Version of the cluster to view
• Add a source for Kubernetes installation.
• Locate the kubeadm version that you want to use.
• Kubeadm should be upgraded.
• View the upgrade strategy
• Removing reliant mirrors
• Upgrade your Kubernetes clusters now.
• Upgrade to the latest versions of kubectl and kubelet.

Kubernetes is a container-running system that provides a serverless experience.

A Kubernetes DaemonSet is a container utility that assures that each node has exactly one copy of a pod operating on it. DaemonSets will also construct the pod on any newly added nodes to your cluster.

Helm Charts are a collection of Kubernetes YAML manifests that may be advertised to your Kubernetes clusters. Installing a Helm Chart into your cluster is as simple as performing a single helm install after it has been packaged, greatly simplifying the deployment of containerized apps.

A Kubernetes operator is a way to package, deploy, and manage Kubernetes applications. The Kubernetes API (application programming interface) and kubectl tooling are used to deploy and manage Kubernetes applications.

CoreDNS is the Kubernetes cluster’s DNS server, acting as a Cluster DNS in accordance with the DNS standards.

ETCD is a simple, secure, and fast distributed, dependable key-value store. It’s used to store and manage the crucial data that keeps dispersed systems working. Kubernetes, the popular container orchestration technology, uses it to manage configuration data, state data, and metadata.

Flannel is a relatively simple overlay network that meets the needs of Kubernetes. Many people have found Flannel and Kubernetes to be successful.

A headless service is one that has a service IP but returns the IPs of our linked Pods instead of load-balancing. Instead of using a proxy, we can interface directly with the Pods.

The statefulset is a device that assists us in installing and managing a group of Kubernetes pods. We can say that the statefulset is a feature that is provided by Kubernetes in which it has installation options for running a container and it provides guarantees regarding the ordering and uniqueness of the pod, such as deployment.

The manifest is a JSON or YAML file that describes a Kubernetes API object. When you apply a manifest, it specifies the desired state of an object that Kubernetes will maintain.

Multus is a latin word that means “many.” It operates as a Multi plugin in Kubernetes and supports numerous network interfaces in a pod, as the name suggests. The Kubernetes Network Custom Resource Definition De-facto Standard is implemented in this project as a reference implementation.

Pause is a Kubernetes hidden container that runs on every pod. The primary responsibility of this container is to keep the namespace open in the event that all of the other containers in the pod fail.

Service discovery is accomplished in Kubernetes using automatically created service names that correspond to the Service’s IP address.

A sidecar, or assistance application, is a secondary container that runs alongside an application container in a Kubernetes pod.

A storageclass is a Kubernetes object that keeps track of the details of building a persistent volume for your pod. You don’t have to establish a persistent volume before claiming it with a storageclass.

Yes, Fortunately, you can try out a few different platforms to run Kubernetes locally, and they’re all open source and licensed under the Apache 2.0 license. Minikube’s key goals are to be the best tool for developing local Kubernetes applications and to support all Kubernetes capabilities that are applicable.

The Kubernetes creators have announced that Windows containers would be supported. To be more explicit, you can now attach Kubernetes to Windows workstations, which can then become “nodes,” allowing you to use some of their memory, disk space, and CPU to run lightweight, virtualized versions of Windows. The beauty of Kubernetes is that you never have to worry about where your virtual machines are.

Google invented Kubernetes to manage its own containerized apps and workloads. In the guise of GKE, Google was also the first cloud vendor to offer a managed Kubernetes service.

“Kubernetes, sometimes known as k8, is an open source platform for automating Linux container operations. “To put it another way, you can group together groups of hosts running Linux containers, and Kubernetes makes managing such clusters simple and efficient.”

The CoreDNS Metrics DNS server keeps records in its database and uses the database to respond to domain name queries. If the DNS server does not have this information, it seeks help from other DNS servers. For Kubernetes 1.13 and later, CoreDNS became the default DNS provider.

The CoreDNS Metrics DNS server keeps records in its database and uses the database to respond to domain name queries. If the DNS server does not have this information, it seeks help from other DNS servers. For Kubernetes 1.13 and later, CoreDNS became the default DNS provider.

Kubernetes networking allows you to configure communication with the Kubernetes network. It also handles a variety of tasks, including as exposing containers to the internet and handling container communication within. Different pods and nodes make up the Kubernetes cluster.

For metrics-based monitoring and alerting, Prometheus on Kubernetes is employed. It gathers real-time data, compresses it, and saves it in a time-series database. The Prometheus sends an HTTP request (pull) named Scrape, which is found in the deployment’s settings.

The  masters per cluster is three.

Out of the box, Kubernetes includes three namespaces.

The overall yearly Kubernetes expenditures are $37,156, with lower RI price for 70% of worker nodes. The size of a master node is determined by the number of Kubernetes nodes in a cluster. The size of the AWS instance provisioned as the master node grows as the number grows.

By default, Kubernetes services are available at ClusterIP, which is an internal IP address that can only be accessed from within the Kubernetes cluster. The ClusterIP enables the service to be accessed by the apps running within the pods. A user can establish a service of type NodePort to make the service available from outside the cluster.

In the right-panel, select the working environment and click Enable next to the Backup & Restore service. Click Next after filling up the backup policy details. You may set up a backup schedule and decide how many backups to keep. Choose which persistent volumes you’d like to back up. Check the box in the title row to back up all volumes ().

If you want to check a pod’s cpu/memory utilization without having to install a third-party application, you can use cgroup to get the memory and cpu usage of the pod. cd /sys/fs/cgroup/cpu for cpu usage kubectl exec -it pod name — /bin/bash Go to pod’s exec mode kubectl exec -it pod name — /bin/bash

Visit the Kubernetes community site to contribute to the Kubernetes community through online forums like Twitter or Stack Overflow, or to learn about local meetups and Kubernetes events. To get started contributing to feature development, read the contributor cheatsheet.