This article explains the evolution of DevOps, the challenges of building a Kubernetes‑based DevOps platform, and how the Open Application Model (OAM) provides a layered, component‑and‑trait architecture that separates concerns, enhances extensibility, and enables next‑generation cloud‑native DevOps solutions.
The article analyzes the limitations of native Kubernetes scheduling, proposes usage‑based and dynamic‑weight scheduling strategies to improve multi‑resource balance, presents experimental results showing significant CPU and memory utilization gains, and discusses cost benefits and future directions for the private cloud platform.
This article reviews Dubbo 3.0’s evolution from its early Alibaba SOA roots to a cloud‑native microservice framework, detailing its open‑source growth, next‑generation RPC protocol, application‑level registration discovery, Kubernetes integration, flexible enhancements, and the roadmap for upcoming releases.
Tencent Cloud MySQL 8.0 builds on official MySQL improvements with eight enterprise‑grade enhancements—TDE encryption, kernel‑level audit, multi‑queue thread pool, strong consistency, AEP SSD support, lightweight AP mode, hotspot updates, and SQL rate‑limiting—delivering high‑performance, secure, and scalable solutions for e‑commerce, gaming, finance, and new‑retail workloads while paving the way for cloud‑native, AI‑driven database evolution.
This article introduces Capability Oriented Architecture (COA), a new design paradigm that abstracts essential capabilities such as power or AI services, making cloud‑edge applications platform‑, location‑, and technology‑agnostic while delegating delivery details to operational components.
This article chronicles Yuque's evolution from a hobbyist prototype to a commercial cloud‑native knowledge platform, detailing its backend migrations, adoption of Node.js, Egg, React, serverless function compute, micro‑service splits, and the architectural lessons learned for stability, cost efficiency, and scalability.
This article reviews Microsoft’s new open‑source portal, Google’s Chrome URL‑hiding experiment, the YAM cryptocurrency bug that locked millions, and the launch of Bootstrap’s official SVG icon library, highlighting their goals, technologies, and community impact.
This article provides a comprehensive analysis of Google’s Borg system, covering its design goals, user view, job and task model, resource allocation, scheduling algorithms, fault tolerance, scalability techniques, and operational metrics that shaped modern cloud‑native orchestration platforms.
This article provides an overview of Kubernetes, explaining its purpose as an open‑source container orchestration platform, recounting its origins from internal Google discussions in 2013, the influence of Borg, the decision to open‑source it, and its subsequent growth into a widely adopted cloud‑native solution.
In this interview, Red Hat’s former chief architect Christian Posta explains how Istio’s architecture has been simplified from a fragmented control plane to the unified Istiod binary, outlines upcoming features in version 1.7, discusses WebAssembly integration, and shares his view on the evolving service‑mesh market.
This article explains how Apache Pulsar’s layered architecture separates I/O modes, uses BookKeeper for durable storage, and leverages multi‑replica write quorums and hierarchical caches to provide efficient tail‑read, catch‑up read, and long‑term storage options such as S3, Azure and GCS.
The article explains Microsoft’s Open Service Mesh (OSM), a lightweight, SMI‑compatible service mesh built on Envoy for Kubernetes, covering its design principles, features, deployment steps, and its role in the broader cloud‑native service‑mesh ecosystem.
This comprehensive article explains what a data lake is, outlines its core characteristics and reference architecture, compares major cloud providers' data‑lake offerings, presents typical advertising and gaming use cases, and proposes a practical, agile process for building and operating a data lake.
This article provides a comprehensive guide to Nginx Ingress on Tencent Cloud TKE, covering its fundamentals, three deployment architectures, selection criteria, internal and external load‑balancer configurations, bandwidth considerations, Ingress creation, and monitoring with Prometheus.
This article provides a comprehensive overview of Kubernetes, explaining its master‑node architecture, core components, deployment workflow, pod fundamentals, scaling and update strategies, networking layers, and service discovery mechanisms, enabling readers to grasp how container orchestration works in practice.
This article explains how cloud‑native principles—combining agile, DevOps, CI/CD, microservices, service governance, container technology, and cloud computing—address modern application challenges such as rapid deployment, elastic scaling, fault detection, self‑healing, and alignment with organizational structures.
Meituan migrated its massive cloud infrastructure from OpenStack to Kubernetes, containerizing over 98 % of services and implementing custom scheduling, NUMA‑aware placement, fine‑grained resource isolation, and an internal management platform that boosted stability above 99.99 %, cut costs, and paved the way for unified VM‑container scheduling and broader cloud‑native workloads.
NetEase Media transformed its infrastructure by containerizing services, establishing multiple resource pools, implementing a ServiceMesh with NSF, and isolating beta and production environments, resulting in higher CPU utilization, automated scaling, and improved stability, while sharing lessons learned and future plans.
This article reviews ten well‑known enterprises—including Adidas, Capital One, Verizon, Disney, and Starbucks—that have undertaken large‑scale DevOps and cloud‑native transformations, detailing the challenges they faced, the cultural and technical changes implemented, and the measurable business benefits achieved.
This article explains how to construct a Kubernetes platform that puts applications first by using the Open Application Model (OAM), covering the required architectural layers, core concepts such as Components, Traits, ApplicationConfiguration, Definition objects, and the practical benefits for platform engineers.
This article introduces Midway Serverless, explains its background in the serverless trend, details its architecture, directory structure, toolchain, dependency‑injection mechanism, anti‑corruption layer, lifecycle hooks, and how it enables seamless migration of traditional Node.js applications to multiple cloud platforms with minimal code changes.
This article explains SkyWalking’s modular, protocol‑oriented and lightweight architecture, its core components, design principles, and advantages such as cross‑environment consistency, easy maintenance, high performance, and extensibility for both traditional and cloud‑native systems.
Discover a curated list of powerful open-source Kubernetes management solutions—including K9s, Rancher, Dashboard, Kubectl, Kubeadm, Helm, KubeSpray, Kontena Lens, and WKSctl—detailing their core features, deployment options, and how they streamline cluster monitoring, configuration, and application lifecycle across cloud-native environments.
This article explains the kubelet’s key responsibilities, how it detects resource scarcity through eviction signals and thresholds, and provides practical guidance on configuring hard and soft eviction policies, reclamation strategies, and QoS‑based pod ranking to keep Kubernetes nodes stable.
This tutorial demonstrates how to configure Docker Hub credentials, create a Tekton Task that builds a Docker image using Kaniko, run the task via TaskRun, and then combine the test and build tasks into a Pipeline and PipelineRun to achieve a complete CI/CD workflow on a Kubernetes cluster.
This guide walks through installing Tekton on a Kubernetes cluster, explains its core CRD resources such as Task, TaskRun, Pipeline and PipelineResource, and demonstrates a complete example that clones a Go repository, runs tests, builds a Docker image, and pushes it to Docker Hub.
The 2020 Cloud‑Native Development Whitepaper, compiled by the China Academy of Information and Communications Technology, offers a data‑driven overview of China’s cloud‑native market size, ecosystem, hot technologies, security frameworks, and emerging industry applications, highlighting four key future trends shaping the sector.
This roundup covers the KubeCon 2020 virtual summit, the GA of seccomp‑based PodSecurityPolicy enforcement, recommended open‑source projects such as Kubernetes The Hard Way and kustomize‑controller, plus a curated list of recent Kubernetes‑focused articles and reading material.
This article traces the birth of middleware, the creation and multi‑generation evolution of SOFAStack at Ant Group, its adoption by banks and insurers, and its shift toward cloud‑native and trustworthy‑native architectures that power large‑scale financial services.
Dubbo-go v1.5 introduces an application‑level service registration model, a metadata center for interface data, Kubernetes‑native registration, enhanced routing, and security features like TLS, while maintaining full compatibility with Dubbo 2.7.x and preparing for future cloud‑native evolution.
This article explains the concept of Service Mesh, why it emerged from micro‑service challenges, its evolution, and compares the main open‑source implementations such as Linkerd, Envoy, Istio, and Conduit, helping readers grasp its role in modern cloud‑native architectures.
iQIYI built a Prometheus‑based microservice monitoring platform that uses Spring Boot Actuator, Micrometer, custom QAE collectors, file‑based service discovery, and an Alert‑proxy to gather container, application, and third‑party metrics, define PromQL alert rules, and forward alerts to its unified notification system, illustrating best practices and lessons learned.
This article introduces NGINX's Microservices Reference Architecture (MRA), explains its three network models—Proxy, Router Mesh, and Fabric—describes their use cases, outlines the goals of the reference architecture, and previews the Ingenious demo application that implements all three models.
Although Docker has become popular for deploying many applications, this article outlines seven technical reasons—ranging from data safety and performance to networking, statefulness, resource isolation, cloud platform limitations, and environment requirements—that make containerizing databases generally impractical, while also suggesting cautious scenarios where it might work.
This article traces Ceph’s evolution from its academic origins to widespread adoption in cloud‑native environments, explains the four stages of storage development, details Ceph’s unified object, block, and file interfaces, and describes its architecture—including monitors, OSDs, CRUSH algorithm, placement groups, and high‑availability features.
A senior infrastructure engineer shares hard‑won lessons from migrating a large team to pure Kubernetes, covering deployment speed, error reduction, observability, networking, monitoring, GitOps, custom operators, secret handling, CI, and logging challenges in modern cloud‑native environments.
This guide walks developers through creating an Alibaba Cloud ACK Kubernetes cluster, importing it into EDAS, initializing a cloud‑native Spring Cloud application, choosing the appropriate runtime, and deploying the app directly from an IDE plugin for fast, efficient releases.
This article introduces Skaffold, a lightweight open‑source CLI tool for local Kubernetes development, explains its key features, shows step‑by‑step installation and a starter workflow, details the pipeline stages and architecture, and includes real‑world user feedback.
This article describes how Dada Group tackled rapid micro‑service growth by designing a language‑agnostic, lightweight service governance and traffic routing engine that uses Consul metadata, configurable routing rules, and link‑based isolation to enable online pressure testing, parallel development, hot‑cold service separation, gray releases, and dynamic rate limiting.
This article examines Docker's early container platform, the evolution of Docker Swarm, the birth and architecture of Kubernetes, and compares their features, scalability, storage, and fault‑tolerance to explain why Kubernetes has become the dominant cloud‑native orchestration solution.
Learn how to construct a scalable, high‑availability cloud call‑center platform using FreeSWITCH, covering PBX basics, dial‑plan routing, media handling, clustering with fs‑router and fs‑media, integration of Kamailio for signaling, and strategies for multi‑tenant, high‑concurrency deployments.
On June 24, 2020 the CNCF Technical Oversight Committee approved eleven projects into the Sandbox, including Crossplane’s OAM Kubernetes implementation, signaling the transfer of ownership to the CNCF community and highlighting upcoming features that will standardize application component dependencies, data injection, and versioning for hybrid‑cloud environments.
This tutorial explains the lifecycle and use‑cases of Kubernetes emptyDir and hostPath volumes, shows how to configure them in pod specs, demonstrates a sidecar pattern for temporary data sharing, and provides complete YAML and kubectl commands for creation, inspection, and troubleshooting.
This article explains how Alibaba's Midway Serverless framework reduces server and governance costs by up to 70%, accelerates front‑end development and deployment, and addresses the benefits, challenges, and operational impacts of adopting a serverless, cloud‑native architecture.
This article presents Ant Group’s financial‑grade unitized architecture, detailing industry‑standard distributed models, the design of RZone/GZone/CZone, its disaster‑recovery, elasticity and gray‑release capabilities, and real‑world banking case studies demonstrating cloud‑native deployment strategies in the financial sector.
Google announced the transfer of the Istio trademark to the newly formed Open Usage Commons, establishing a neutral base for the project's branding while outlining continued open governance, community involvement, and future stewardship of the service‑mesh ecosystem.
This article reviews JD Cloud’s bastion host solution presented at the 2020 Global New‑Generation Software Engineering Summit, detailing the security challenges of modern operations, compliance requirements, design principles, cloud‑native architecture, and real‑world deployments in enterprises and finance.
This article explains how Kubernetes' Kube‑scheduler has evolved from early Extender and multiple‑scheduler approaches to the modern Scheduling Framework, detailing its architecture, extension points, and a step‑by‑step guide to building a custom QoS plugin with code examples.
This guide explains Kubernetes' security pipeline—authentication, authorization, and admission control—detailing token and SSL authentication, service accounts, RBAC, ABAC, Node and Webhook authorizers, and the essential admission plugins, with practical kubectl commands and configuration examples.
This guide walks through generating a private key, CSR, and signed certificate with OpenSSL, adding a new user and context to kubeconfig, binding the user to a cluster role, and verifying namespace‑specific permissions in a Kubernetes cluster.
This article examines the evolving relationship between Service Mesh and API Gateway, clarifying their original responsibilities, discussing traffic direction semantics, and detailing how sidecar integration, BFF layers, and real‑world Ant Financial practices are driving a convergence toward more decentralized, cloud‑native API management.
Midway Serverless v1.0 introduces a cloud‑native, TypeScript‑based framework that unifies front‑end and back‑end development, simplifies platform migration, prevents vendor lock‑in, and leverages existing koa and egg ecosystems to dramatically improve development efficiency.
This guide walks through downloading the mysql_exporter package, extracting it on a Kubernetes master, installing the binary, creating a dedicated MySQL user with proper permissions, configuring a password‑less client file, launching the exporter, and updating Prometheus via kubectl so MySQL metrics are exposed on port 9104.
This article examines the limitations of traditional Kubernetes Service implementations, introduces Tencent TKE’s IPVS‑BPF mode that bypasses nf_conntrack using eBPF for SNAT, details its design and implementation steps, and presents extensive performance measurements showing significant latency and throughput improvements.
This article introduces Spring Cloud as a microservice framework, explains the fundamentals of service architecture, compares SOA and microservices, and walks through essential components such as service registration, discovery, load‑balanced calls, circuit breakers, gateways, configuration management, message bus, and tracing with practical code examples.
This article introduces OpenYurt's YurtHub component, detailing its architecture and five major extensions—including edge network autonomy, multi‑cloud endpoint support, node‑level flow control, certificate rotation, and additional features—while explaining how it enables non‑intrusive Kubernetes edge deployments.
This comprehensive guide explains why Kubernetes has become the standard container platform, covering its application‑centric architecture, migration challenges, networking and CNI design, control‑plane components, storage solutions including CSI and FlexVolume, image distribution strategies, upgrade and backup procedures, operator patterns, and practical containerization best practices for large‑scale deployments.
This guide walks you through installing KubeSphere 2.1.1 on a Kubernetes cluster, covering prerequisites, Helm and Tiller setup, OpenEBS storage configuration, optional minimal or full installations, and verification steps, with detailed commands and tips for both online and air‑gapped environments.
This article explains the fundamentals of Ceph, a high‑performance, highly available and scalable distributed storage system, covering its architecture, core components, data placement algorithms, storage interfaces, and typical deployment scenarios in cloud environments.
Lens, a powerful Kubernetes desktop IDE, offers real-time cluster monitoring, multi-cluster management via kubeconfig, built-in kubectl compatibility, resource utilization dashboards, and an integrated Helm chart store, making it a superior alternative to older tools like Kubernetic for system engineers.
TiDB is an open‑source, cloud‑native distributed relational database that combines OLTP and OLAP capabilities, offers horizontal elasticity, strong ACID transactions, MySQL compatibility, and is suited for high‑availability, large‑scale, real‑time analytics scenarios across various industries.
The article explains how the Open Application Model (OAM) addresses the missing "application" concept in Kubernetes by providing a standardized, role‑based model for defining, configuring, and delivering cloud‑native applications, and describes the joint Alibaba‑Microsoft‑Crossplane implementation, its runtime library, and the growing community ecosystem.
In this interview, senior engineers from Lingque Cloud share how their company adopted Kubernetes six years ago, discuss the evolution of the platform, their contributions to the open‑source community, and their expectations for the future of cloud‑native technologies.
The talk reviews Serverless origins, defines its cloud‑native architecture that lets developers focus on business logic, highlights benefits like pay‑per‑use scaling, demonstrates rapid Next.js SSR deployment via the Serverless Framework with built‑in monitoring, and outlines a top‑down development and operations workflow.
This article presents ByteDance's private cloud platform TCE architecture and explains how automated elastic scaling, dynamic over‑commit, and mixed‑workload deployment are used to improve resource utilization for millions of services, balancing online peak demand with offline batch tasks.
This extensive tutorial explains Linux containers and Docker fundamentals, compares containers with virtualization, outlines Docker's history, demonstrates installation steps, covers essential Docker commands, image lifecycle management, Dockerfile creation, container networking options, Docker Compose orchestration, private registry setup, Harbor deployment, and best practices for production use.
This roundup highlights recent Kubernetes ecosystem changes, including the addition of anti‑discrimination statements to documentation, the upcoming 1.19.0‑beta.1 code freeze, Linkerd 2.8 multi‑cluster support, several upstream enhancements, and curated open‑source project and reading recommendations for cloud‑native practitioners.
The article reviews the rapid growth of Serverless in China, highlights key technical and cost challenges, outlines Tencent Cloud’s ecosystem, product, and community initiatives—including the 1 ms billing granularity—and cites industry recognition such as Forrester’s Top‑3 ranking.
Linkerd 2.8 adds a multi‑cluster extension that securely connects Kubernetes clusters across any network topology, introduces an add‑on plugin system with Jaeger and Grafana support, and includes numerous performance and stability improvements for cloud‑native service mesh deployments.
This article explains OpenYurt’s non‑intrusive architecture that extends native Kubernetes to edge scenarios, detailing its edge‑autonomy features, the challenges it solves, and the two main design approaches—kubelet reconstruction and the YurtHub proxy—along with their trade‑offs and implementation details.
This article explains the concept, benefits, and technical implementation of in‑place upgrades for Pods in Kubernetes, detailing how OpenKruise leverages kubelet image hashing, update restrictions, container status reporting, and readiness gates to achieve fast, low‑impact, and controllable rollouts.
This article explores the evolving concept of cloud native, comparing definitions from Pivotal and CNCF, detailing essential technologies such as containers, Kubernetes, Service Mesh, and IaC, and offers practical guidance on building, delivering, and adopting cloud‑native applications.
This guide walks through systematic Kubernetes troubleshooting steps for pods stuck in Pending, Waiting, CrashLoopBackOff, or Running incorrectly, and also covers controller, service, and network debugging using kubectl commands, log inspection, validation flags, and endpoint verification.
This article explains why Helm is essential for managing Kubernetes applications, describes its core concepts of charts, releases, and repositories, and provides a step‑by‑step guide to integrating Helm with Docker and Sonatype Nexus in a CI/CD pipeline, including practical commands and code examples.
This article explains how Envoy, a lightweight high‑performance L7 proxy and communication bus, provides non‑intrusive sidecar architecture, multi‑layer networking, HTTP/2 support, dynamic configuration, gRPC and special protocol handling, and built‑in observability for cloud‑native systems.
Monzo, the UK digital bank, shares how it built a Kubernetes‑based, cloud‑native platform to run over 1,600 Go‑written microservices backed by Cassandra, implements fine‑grained service isolation with network policies, and creates internal tooling to automate security and deployment at massive scale.
This article traces the evolution from early virtualization challenges to modern container technologies, explaining how LXC laid the groundwork for Docker, how Docker differs from virtual machines, and why containers have become essential for cloud‑native development and DevOps workflows.
This article details Autohome's use of Apache Kylin as its core OLAP engine, covering its architecture, large‑scale Cube deployment, real‑world business applications, a series of performance and operational optimizations, cluster upgrade experiences, and upcoming plans for real‑time OLAP and cloud‑native evolution.
This article explains the fundamentals and challenges of edge computing, compares it with centralized cloud, outlines current research hotspots, and details Tencent's TKE@edge solution—including its architecture and key components—that adapts Kubernetes for edge environments.
This article explains the fundamentals of Serverless computing, compares FaaS and BaaS offerings, examines the limitations of cloud functions, and details how Tencent CloudBase leverages Knative to deliver Serverless cloud applications, covering serving, building, ecosystem integration, and the emerging CaaS model.
This comprehensive guide walks you through Linux containers, Docker fundamentals, installation, command‑line usage, image lifecycle, Dockerfile creation, registry setup (including authentication), Docker Compose orchestration, networking options, restart policies, Harbor deployment, best practices, and monitoring techniques.
This guide details a zero‑downtime migration of large ZooKeeper clusters to Kubernetes by wrapping each server in a ClusterIP service, reconfiguring clients, updating server configs, and replacing physical nodes with Pods, while outlining required network prerequisites and practical steps.
This article analyses the shortcomings of fragmented operations platforms, explains how organizational and business domain factors shape a successful ops middle platform, and presents a lifecycle‑driven, multi‑layer integration approach for building a scalable, cloud‑native operations ecosystem.
This article outlines the design, functional requirements, CRD definition, architecture, deployment, scaling, monitoring, fault‑tolerance, and upgrade strategies of a Zookeeper operator on Kubernetes, including code examples, service configurations, and integration with Prometheus and OAM standards.
This guide explains Kubernetes service exposure options, the challenges they address, and provides a step‑by‑step tutorial for deploying an Ingress controller, creating Ingress resources, and configuring TLS to securely expose applications within a cluster.
This article walks beginners through the full process of preparing a Kubernetes environment and deploying both PHP (WordPress) and Java (Tomcat) web applications, covering image creation, namespace setup, secrets, deployments, services, ingress configuration, and host binding.
This article provides a comprehensive introduction to microservice architecture, covering service decomposition, registration and discovery methods, client‑driven load balancing, rate‑limiting and circuit‑breaking strategies, and the design of a self‑built application delivery platform for cloud‑native environments.
This article details how Tubi built the Tubi Data Runtime platform on JupyterHub using Kubernetes, covering authentication with Okta SSO, custom Docker images, shared EFS storage, multi‑service support, GPU enablement, node affinity, cluster autoscaling, and monitoring with Prometheus.
This article provides a comprehensive guide to Docker images, covering core concepts, image sources, essential commands for searching, pulling, tagging, inspecting, pruning, exporting, importing, and pushing images, along with practical examples and tips for effective container image management.
This article analyzes a recurring NotReady issue in Alibaba Cloud Kubernetes clusters, explaining how kubelet, NodeStatus, and the Pod Lifecycle Events Generator (PLEG) interact, why nodes become Ready for only three minutes after a kubelet restart, and how the underlying timeout mechanisms cause the problem.
This article explains how container technology, inspired by shipping containers, transforms software delivery with modular, lightweight virtualization, and how Alibaba Cloud’s container services—ACK, ASK, ACR, and ASM—provide agile, elastic, portable, and secure cloud‑native solutions for hybrid and multi‑cloud environments.
This article explains the Kubernetes update mechanism, why an API update can fail due to missing resourceVersion, how patch operations differ, and the internal logic of kubectl apply and edit, providing practical guidance for choosing between update and patch in cloud‑native deployments.
This article examines why MySQL is deployed on Kubernetes, outlines the technical challenges such as service routing, monitoring isolation, storage and high‑availability, highlights the benefits of cloud‑native networking and scheduling, and reviews popular MySQL operators and their implementation details.
This article provides a comprehensive technical overview of Tencent Cloud's TBase database, covering fundamental database classifications, TBase's cloud‑native architecture, distributed transaction mechanisms, storage and compute separation, security layers, backup strategies, and real‑world deployment cases.
This article explains how leveraging edge computing, CDN‑based SSR caching, and TESI tags can dramatically improve first‑screen performance, reduce server pressure, and enable efficient static rendering for massive, mostly static content while maintaining up‑to‑date data and robust fallback mechanisms.
The article recaps a SIG Cloud‑Provider‑Alibaba webinar, detailing Alibaba’s large‑scale cloud‑native deployment challenges and how the open‑source OpenKruise project introduces extended workloads like CloneSet, Advanced StatefulSet, SidecarSet, and more to improve deployment efficiency, stability, and flexibility on Kubernetes.
This article describes the design and implementation of a Serverless‑based one‑stop node service management platform, covering its full‑stack engineering architecture, frontend and backend project organization, logging, process monitoring, one‑click deployment, and a comparison of Serverless solutions, while sharing practical challenges and technical solutions.
The Istio 1.6 release introduces a fully migrated Istiod architecture, streamlined installation and upgrade processes, expanded observability features, native support for virtual‑machine workloads via WorkloadEntry, and several network enhancements including improved secret handling and experimental Service API support.
This guide explains how to set up Istio across multiple Kubernetes clusters using a multi‑control‑plane topology, covering CA secret creation, control‑plane installation, DNS configuration, sample application deployment, ServiceEntry and DestinationRule creation, and cross‑cluster traffic routing verification.
OpenKruise v0.5.0 introduces CloneSet maxSurge rollout and SidecarSet volume‑merge capabilities, addressing native Kubernetes limitations by allowing expand‑then‑shrink deployments, in‑place upgrades, and seamless sidecar injection without volume conflicts for large‑scale cloud‑native applications.
