Podcast
Questions and Answers
What role does the controller manager play in a Kubernetes cluster?
What role does the controller manager play in a Kubernetes cluster?
Kubelet interacts exclusively with the Docker runtime to manage containers.
Kubelet interacts exclusively with the Docker runtime to manage containers.
False
What is the purpose of the kube proxy in a Kubernetes architecture?
What is the purpose of the kube proxy in a Kubernetes architecture?
It configures and manages the networking for applications and services.
What is the primary function of a Pod in Kubernetes?
What is the primary function of a Pod in Kubernetes?
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A Pod can be recreated after its termination.
A Pod can be recreated after its termination.
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The __________ provides a REST interface for managing resources in a Kubernetes cluster.
The __________ provides a REST interface for managing resources in a Kubernetes cluster.
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Match the following Kubernetes components with their functions:
Match the following Kubernetes components with their functions:
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What YAML command is used to create a Pod?
What YAML command is used to create a Pod?
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The __________ attribute in a Pod YAML file identifies the object as a Pod.
The __________ attribute in a Pod YAML file identifies the object as a Pod.
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Match the following Pod components with their descriptions:
Match the following Pod components with their descriptions:
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What is the primary function of container orchestration platforms?
What is the primary function of container orchestration platforms?
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Kubernetes was initially developed by Microsoft and is a proprietary platform.
Kubernetes was initially developed by Microsoft and is a proprietary platform.
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What component of the Kubernetes control plane handles all requests to the cluster?
What component of the Kubernetes control plane handles all requests to the cluster?
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The _______ database is used by Kubernetes to store cluster configuration and runtime state.
The _______ database is used by Kubernetes to store cluster configuration and runtime state.
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What does Container as a Service (CaaS) primarily provide?
What does Container as a Service (CaaS) primarily provide?
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The Cloud Native Computing Foundation (CNCF) is associated exclusively with proprietary software.
The Cloud Native Computing Foundation (CNCF) is associated exclusively with proprietary software.
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Name one key characteristic of Container as a Service (CaaS).
Name one key characteristic of Container as a Service (CaaS).
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The Cloud Native Landscape Project aims to help enterprises navigate the previously uncharted terrain of _______ technologies.
The Cloud Native Landscape Project aims to help enterprises navigate the previously uncharted terrain of _______ technologies.
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Match the following terms with their descriptions:
Match the following terms with their descriptions:
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Study Notes
Kubernetes and Cloud-Native Applications
- Kubernetes is a container orchestration platform, initially developed by Google and released as an open-source project in 2014.
- It is a de facto standard container-as-a-service (CaaS) platform.
- Trajche Krstev is a Solution Architect for Packet Core and Telco Cloud.
Agenda
- Container as a Service (CaaS)
- Cloud evolution
- The path to cloud native
- Cloud Native Trail Map
- Containers background
- Kubernetes architecture
- Kubernetes overview
Container as a Service (CaaS)
- CaaS is a cloud computing model that manages, deploys, and scales containerized applications.
- It streamlines container lifecycle management (provisioning, scheduling, scaling, and monitoring).
- Key features include container management, orchestration support, flexibility across cloud environments (hybrid, public, private), and API-driven automation.
- Benefits include developer efficiency, portability, pay-as-you-go pricing, and rapid deployment.
The Cloud Evolution
- Legacy systems face challenges like hardware coupling, monolithic architectures, limited scaling, and low automation.
- IaaS systems offer hardware independence, but limited scaling and partial automation.
- Virtual Network Functions (VNF) systems have hardware independence, mostly monolithic, and limited scaling.
- Cloud native systems feature microservices architecture, high availability, continuous deployment, full automation, and complete hardware independence.
- CaaS platforms like Kubernetes offer a modern approach to cloud computing.
The Path to Cloud Native
- The Cloud Native Computing Foundation (CNCF) is the Linux Foundation community for containers and cloud-native applications.
- CNCF hosts open-source projects like Kubernetes, key to realizing cloud-native applications.
- The Cloud Native Landscape Project is a resource map for enterprises and developers transitioning to cloud-native technologies.
- CNCF projects represent a well-established path for cloud-native application deployment.
The Cloud Native Trail Map
- Addresses containerization, continuous integration/continuous delivery (CI/CD), orchestration and application definition, observability and analysis, service proxy, discovery, and mesh, networking, policy, security, distributed database, and storage, container registry, and runtime, and software distribution.
- This trail map assists in navigating the cloud-native journey.
Containers Background
- Containers provide a sandboxed execution environment for processes.
- Container images are stored in registries.
- Containers are lightweight, focusing on process-level CPU/memory usage.
- Filesystem layers are shared among containers.
- Communications are enabled through bridges or similar inter-process communication methods.
- Docker images are stored in a registry and can be retrieved by name and version.
- Containers run in a single server or can be orchestrated across multiple servers.
Kubernetes Architecture
- Kubernetes is an orchestration platform that manages containerized applications.
- Control plane: Master nodes for high availability (typically replicated). Includes components like API server, controller manager, scheduler, and etcd.
- Runtime plane: Worker nodes (minions). For deploying and managing Pods.
- Kubernetes architecture is comprised of the control plane (managing applications), worker nodes (executing tasks), Kubernetes API (to allow external access), and Container Runtime Interface (CRI).
- Kubectl refers to the command-line tool for interacting with Kubernetes. The kubeconfig file automatically discovers API endpoints and credentials.
- There are namespaces for light multitenancy and resource quota enforcement.
Kubernetes - Architecture (Control Plane)
- The API server interacts with clients and supports REST-based APIs. It acts as the gateway for all control plane components.
- Kubernetes uses etcd to store cluster configuration, runtime state, and metadata. This ensures data consistency and availability for the control plane.
- The scheduler assigns Pods to appropriate nodes according to various cluster policies.
- The controller manager orchestrates Kubernetes resources (nodes, workloads, configurations), continuously monitoring and maintaining appropriate cluster states.
- The cloud controller manager interacts with the underlying cloud and integrates with cloud providers.
Kubernetes - Architecture (User Plane)
- Kubelet is the control plane agent in every worker node, managing the execution of containers.
- Kube-proxy is responsible for network configurations for applications and services, including CoreDNS handling for DNS resolution.
- The container runtime manages container execution and interactions (e.g., Docker).
- Container Runtime Interface (CRI) governs container runtime specifications, interfaces, and APIs used by kubelet.
- Container Network Interface (CNI) provides a standard interface between the container runtime and networking.
Kubernetes Cluster, Pods, Deployments, and Services
- Kubernetes deployments manage Pods.
- Pods are the smallest deployable units in Kubernetes.
- Deployments define and manage the number of Pod replicas.
- Services act as an abstraction layer for accessing network Pods.
Kubernetes - Pod Storage (Volumes)
- Volumes provide storage space that survives the lifecycle of individual containers within a Pod.
- Persistent volumes (PVs) are storage resources for Kubernetes.
- Persistent volume claims (PVCs) describe the storage needs of applications.
Kubernetes Pod Resource Usage
- Requests (minimum) and limits (maximum) can control CPU and memory resources of containers within a Pod.
- This guarantees sufficient resources and prevents overconsumption.
Kubernetes Pod Configuration
- ConfigMaps serve as keys for Pod configurations (properties and init values).
- They are similar to .properties or .ini files and support YAML definitions.
Kubernetes Deployments
- Deployments maintain a set of Pods, defining their replicas.
- Kubernetes manages Pod creation and ensures a specified number of running instances.
Other Workload Controller Use Cases
- Deployments: Suitable for deploying stateless applications by specifying a number of replicas to achieve high availability for stateless applications.
- StatefulSets: Manage stateful applications, guaranteeing their persistent state and ordered creation/termination.
- DaemonSets: Configure applications that run on each node, like monitoring/supervision components.
- Jobs: Run tasks with guaranteed completion, like data initialization tasks.
- CronJobs: Run tasks at scheduled intervals for maintenance or other periodic operations.
Kubernetes Services
- Services in Kubernetes act as an abstraction layer, providing external access to Pods.
- Different service types (ClusterIP, NodePort, LoadBalancer, ExternalName) control access within and outside the cluster.
Kubernetes Networking Basics
- Every Pod has a single network interface and a unique IP address.
- Kubernetes uses a cluster network shared among all Pods and services.
- Network Policies allow controlling communication among Pods.
- An ingress network connects pods to the internet and receives external traffic to the cluster.
Kubernetes Receiving External Traffic
- By default, Pods and Services are only accessible within the Kubernetes cluster.
- Admins must configure external connectivity using methods such as exposing individual Pods (not recommended), exposing Services, and using an Ingress resource.
Kubernetes Scaling
- Deployments, StatefulSets, and other Kubernetes resources can be scaled automatically by using HorizontalPodAutoscalers.
- These tools can automatically adjust resource metrics such as CPU and memory, or use custom metrics.
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Description
Explore the fundamental concepts of Kubernetes and its role in cloud-native applications. This quiz covers container as a service, Kubernetes architecture, and the overall cloud evolution trail map. Test your understanding of container management and the advantages of adopting cloud-native practices.
