Glossary
Este glossário pretende ser uma lista padronizada e abrangente da terminologia do Kubernetes. Inclui termos técnicos específicos dos K8s, além de termos mais gerais que fornecem um contexto útil.
Filtrar termos de acordo com suas tags
Clique nos [+] indicadores abaixo para uma maior explicação sobre um termo em particular.
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Add-onsLINK
Resources that extend the functionality of Kubernetes.
[+]Installing addons explains more about using add-ons with your cluster, and lists some popular add-ons.
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Admission ControllerLINK
A piece of code that intercepts requests to the Kubernetes API server prior to persistence of the object.
[+]Admission controllers are configurable for the Kubernetes API server and may be "validating", "mutating", or both. Any admission controller may reject the request. Mutating controllers may modify the objects they admit; validating controllers may not.
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AffinityLINK
In Kubernetes, affinity is a set of rules that give hints to the scheduler about where to place pods.
[+] -
Agente de execução de contêinerLINK
O agente de execução (runtime) de contêiner é o software responsável por executar os contêineres.
[+]O Kubernetes suporta diversos agentes de execução de contêineres: Docker, containerd, CRI-O, e qualquer implementação do Kubernetes CRI (Container Runtime Interface).
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Aggregation LayerLINK
The aggregation layer lets you install additional Kubernetes-style APIs in your cluster.
[+]When you've configured the Kubernetes API Server to support additional APIs, you can add
APIService
objects to "claim" a URL path in the Kubernetes API. -
AnnotationLINK
A key-value pair that is used to attach arbitrary non-identifying metadata to objects.
[+]The metadata in an annotation can be small or large, structured or unstructured, and can include characters not permitted by labels. Clients such as tools and libraries can retrieve this metadata.
-
API GroupLINK
A set of related paths in Kubernetes API.
[+]You can enable or disable each API group by changing the configuration of your API server. You can also disable or enable paths to specific resources. API group makes it easier to extend the Kubernetes API. The API group is specified in a REST path and in the
apiVersion
field of a serialized object.- Read API Group for more information.
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API serverLINKTambém conhecido como:kube-apiserver
O servidor de API é um componente da Camada de gerenciamento do Kubernetes que expõe a API do Kubernetes. O servidor de API é o front end para a camada de gerenciamento do Kubernetes.
[+]A principal implementação de um servidor de API do Kubernetes é kube-apiserver. O kube-apiserver foi projetado para ser escalonado horizontalmente — ou seja, ele pode ser escalado com a implantação de mais instâncias. Você pode executar várias instâncias do kube-apiserver e balancear (balanceamento de carga, etc) o tráfego entre essas instâncias.
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API-initiated evictionLINK
API-initiated eviction is the process by which you use the Eviction API to create an
[+]Eviction
object that triggers graceful pod termination.You can request eviction either by directly calling the Eviction API using a client of the kube-apiserver, like the
kubectl drain
command. When anEviction
object is created, the API server terminates the Pod.API-initiated eviction is not the same as node-pressure eviction.
-
App ContainerLINK
Application containers (or app containers) are the containers in a pod that are started after any init containers have completed.
[+]An init container lets you separate initialization details that are important for the overall workload, and that don't need to keep running once the application container has started. If a pod doesn't have any init containers configured, all the containers in that pod are app containers.
-
Application ArchitectLINK
A person responsible for the high-level design of an application.
[+]An architect ensures that an app's implementation allows it to interact with its surrounding components in a scalable, maintainable way. Surrounding components include databases, logging infrastructure, and other microservices.
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ApproverLINK
A person who can review and approve Kubernetes code contributions.
[+]While code review is focused on code quality and correctness, approval is focused on the holistic acceptance of a contribution. Holistic acceptance includes backwards/forwards compatibility, adhering to API and flag conventions, subtle performance and correctness issues, interactions with other parts of the system, and others. Approver status is scoped to a part of the codebase. Approvers were previously referred to as maintainers.
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Camada de gerenciamentoLINKA camada de gerenciamento de contêiner que expõe a API e as interfaces para definir, implantar e gerenciar o ciclo de vida dos contêineres. [+]
A camada de gerenciamento de contêiner que expõe a API e as interfaces para definir, implantar e gerenciar o ciclo de vida dos contêineres.
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CLA (Contributor License Agreement)LINK
Terms under which a contributor grants a license to an open source project for their contributions.
[+]CLAs help resolve legal disputes involving contributed material and intellectual property (IP).
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Cloud Native Computing Foundation (CNCF)LINK
A Cloud Native Computing Foundation (CNCF) constrói um ecossistema sustentável e promove uma comunidade no entorno dos projetos que orquestram contêineres como parte de uma arquitetura de microserviços.
Kubernetes é um projeto CNCF.
[+]A CNCF é uma sub-fundação da Linux Foundation. Sua missão é tornar a computação nativa em nuvem onipresente.
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Cloud ProviderLINKTambém conhecido como:Cloud Service Provider
A business or other organization that offers a cloud computing platform.
[+]Cloud providers, sometimes called Cloud Service Providers (CSPs), offer cloud computing platforms or services.
Many cloud providers offer managed infrastructure (also called Infrastructure as a Service or IaaS). With managed infrastructure the cloud provider is responsible for servers, storage, and networking while you manage layers on top of that such as running a Kubernetes cluster.
You can also find Kubernetes as a managed service; sometimes called Platform as a Service, or PaaS. With managed Kubernetes, your cloud provider is responsible for the Kubernetes control plane as well as the nodes and the infrastructure they rely on: networking, storage, and possibly other elements such as load balancers.
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ClusterLINK
Um conjunto de servidores de processamento, chamados nós, que executam aplicações containerizadas. Todo cluster possui ao menos um servidor de processamento (worker node).
[+]O servidor de processamento hospeda os Pods que são componentes de uma aplicação. O ambiente de gerenciamento gerencia os nós de processamento e os Pods no cluster. Em ambientes de produção, o ambiente de gerenciamento geralmente executa em múltiplos computadores e um cluster geralmente executa em múltiplos nós (nodes) , provendo tolerância a falhas e alta disponibilidade.
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Cluster OperationsLINK
The work involved in managing a Kubernetes cluster: managing day-to-day operations, and co-ordinating upgrades.
[+]Examples of cluster operations work include: deploying new Nodes to scale the cluster; performing software upgrades; implementing security controls; adding or removing storage; configuring cluster networking; managing cluster-wide observability; and responding to events.
-
Cluster OperatorLINK
A person who configures, controls, and monitors clusters.
[+]Their primary responsibility is keeping a cluster up and running, which may involve periodic maintenance activities or upgrades.
Note: Cluster operators are different from the Operator pattern that extends the Kubernetes API. -
Code ContributorLINK
A person who develops and contributes code to the Kubernetes open source codebase.
[+]They are also an active community member who participates in one or more Special Interest Groups (SIGs).
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ConfigMapLINK
An API object used to store non-confidential data in key-value pairs. Pods can consume ConfigMaps as environment variables, command-line arguments, or as configuration files in a volume.
[+]A ConfigMap allows you to decouple environment-specific configuration from your container images, so that your applications are easily portable.
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Container Environment VariablesLINK
Container environment variables are name=value pairs that provide useful information into containers running in a pod
[+]Container environment variables provide information that is required by the running containerized applications along with information about important resources to the containers. For example, file system details, information about the container itself, and other cluster resources such as service endpoints.
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Container Lifecycle HooksLINK
The lifecycle hooks expose events in the Container management lifecycle and let the user run code when the events occur.
[+]Two hooks are exposed to Containers: PostStart which executes immediately after a container is created and PreStop which is blocking and is called immediately before a container is terminated.
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Container network interface (CNI)LINK
Plugins Container network interface (CNI) são um tipo de plugin de Rede em conformidade com a especificação appc/CNI.
[+]- Para informações sobre Kubernetes e CNI, veja aqui.
- Para informações sobre Kubernetes e CNI, veja "Plugins de rede".
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Container Storage Interface (CSI)LINK
The Container Storage Interface (CSI) defines a standard interface to expose storage systems to containers.
[+]CSI allows vendors to create custom storage plugins for Kubernetes without adding them to the Kubernetes repository (out-of-tree plugins). To use a CSI driver from a storage provider, you must first deploy it to your cluster. You will then be able to create a Storage Class that uses that CSI driver.
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containerdLINK
Um agente de execução de contêiner com enfase em simplicidade, robustez e portabilidade
[+]containerd é um agente de execução de contêiner que executa um serviço no Linux ou Windows. containerd é responsável por buscar e armazenar as imagens de contêiner, executar contêineres, prover acesso à rede e mais.
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ContributorLINK
Someone who donates code, documentation, or their time to help the Kubernetes project or community.
[+]Contributions include pull requests (PRs), issues, feedback, special interest groups (SIG) participation, or organizing community events.
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ControladorLINK
No Kubernetes, controladores são ciclos de controle que observam o estado do seu cluster, e então fazer ou requisitar mudanças onde necessário. Cada controlador tenta mover o estado atual do cluster mais perto do estado desejado.
[+]Controladores observam o estado partilhado do cluster através do apiserver (parte do Camada de gerenciamento).
Alguns controladores também correm dentro do plano de controle, fornecendo ciclos de controle que são centrais às operações do Kubernetes. Por exemplo: o controlador de deployments, o controlador de daemonsets, o controlador de namespaces, e o controlador de volumes persistentes (persistent volumes) (e outros) todos correm dentro do kube-controller-manager.
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CRI-OLINK
Uma ferramenta que permite você usar agentes de execução de contêineres OCI com o CRI do Kubernetes
[+]CRI-O é uma implementação do Container runtime interface (CRI) que permite usar agentes de execução de contêiner compatíveis com as especificações da Open Container Initiative (OCI).
Usar o CRI-O permite ao Kubernetes utilizar-se de qualquer agente de execução compatível com o OCI para executar Pods, e obter imagens de contêineres de registros remotos.
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CustomResourceDefinitionLINK
Código customizado que define um recurso a ser adicionado ao seu servidor de API Kubernetes sem a necessidade de construir um servidor customizado.
[+]CustomResourceDefinitions permitem você extender a API do Kubernetes para seu ambiente caso as APIs atuais não cumpram com seus requisitos.
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DeploymentLINK
An API object that manages a replicated application, typically by running Pods with no local state.
[+]Each replica is represented by a Pod, and the Pods are distributed among the nodes of a cluster. For workloads that do require local state, consider using a StatefulSet.
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Developer (disambiguation)LINK
May refer to: Application Developer, Code Contributor, or Platform Developer.
[+]This overloaded term may have different meanings depending on the context
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Device PluginLINK
Device plugins run on worker Nodes and provide Pods with access to resources, such as local hardware, that require vendor-specific initialization or setup steps.
[+]Device plugins advertise resources to the kubelet, so that workload Pods can access hardware features that relate to the Node where that Pod is running. You can deploy a device plugin as a DaemonSet, or install the device plugin software directly on each target Node.
See Device Plugins for more information.
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DisruptionLINK
Disruptions are events that lead to one or more Pods going out of service. A disruption has consequences for workload resources, such as Deployment, that rely on the affected Pods.
[+]If you, as cluster operator, destroy a Pod that belongs to an application, Kubernetes terms that a voluntary disruption. If a Pod goes offline because of a Node failure, or an outage affecting a wider failure zone, Kubernetes terms that an involuntary disruption.
See Disruptions for more information.
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DockerLINK
Docker (specifically, Docker Engine) is a software technology providing operating-system-level virtualization also known as containers.
[+]Docker uses the resource isolation features of the Linux kernel such as cgroups and kernel namespaces, and a union-capable file system such as OverlayFS and others to allow independent containers to run within a single Linux instance, avoiding the overhead of starting and maintaining virtual machines (VMs).
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Downstream (disambiguation)LINK
May refer to: code in the Kubernetes ecosystem that depends upon the core Kubernetes codebase or a forked repo.
[+]- In the Kubernetes Community: Conversations often use downstream to mean the ecosystem, code, or third-party tools that rely on the core Kubernetes codebase. For example, a new feature in Kubernetes may be adopted by applications downstream to improve their functionality.
- In GitHub or git: The convention is to refer to a forked repo as downstream, whereas the source repo is considered upstream.
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Dynamic Volume ProvisioningLINK
Allows users to request automatic creation of storage Volumes.
[+]Dynamic provisioning eliminates the need for cluster administrators to pre-provision storage. Instead, it automatically provisions storage by user request. Dynamic volume provisioning is based on an API object, StorageClass, referring to a Volume Plugin that provisions a Volume and the set of parameters to pass to the Volume Plugin.
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EndpointsLINK
Endpoints track the IP addresses of Pods with matching selectors.
[+]Endpoints can be configured manually for Services without selectors specified. The EndpointSlice resource provides a scalable and extensible alternative to Endpoints.
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EndpointSliceLINK
A way to group network endpoints together with Kubernetes resources.
[+]A scalable and extensible way to group network endpoints together. These can be used by kube-proxy to establish network routes on each node.
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Ephemeral ContainerLINK
A Container type that you can temporarily run inside a Pod.
[+]If you want to investigate a Pod that's running with problems, you can add an ephemeral container to that Pod and carry out diagnostics. Ephemeral containers have no resource or scheduling guarantees, and you should not use them to run any part of the workload itself.
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Esquemas alternativos x509LINK[+]
X.509 é um formato padrão para certificados de chave pública, documentos digitais que associam com segurança pares de chaves criptográficas a identidades como sites, indivíduos ou organizações.
Introduzido pela primeira vez em 1988 junto com os padrões X.500 para serviços de diretório eletrônico, o X.509 foi adaptado para uso na Internet pelo grupo de trabalho Public-Key Infrastructure (X.509) (PKIX) da IETF. O RFC 5280 define o perfil do certificado X.509 v3, a lista de revogação de certificado X.509 v2 (CRL) e descreve um algoritmo para a validação do caminho do certificado X.509.
As aplicações comuns de certificados X.509 incluem:
- SSL / TLS e HTTPS para navegação na web autenticada e criptografada - E-mail assinado e criptografado por meio do protocolo S / MIME - Assinatura de código - Assinatura de documento - Autenticação de cliente - Identificação eletrônica emitida pelo governo
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etcdLINK
Armazenamento do tipo Chave-Valor consistente e em alta-disponibilidade usado como repositório de apoio do Kubernetes para todos os dados do cluster.
[+]Se o seu cluster Kubernetes usa etcd como seu armazenamento de apoio, certifique-se de ter um plano de back up para seus dados.
Você pode encontrar informações detalhadas sobre o etcd na seção oficial da documentação.
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ExtensionsLINK
Extensions are software components that extend and deeply integrate with Kubernetes to support new types of hardware.
[+]Most cluster administrators will use a hosted or distribution instance of Kubernetes. As a result, most Kubernetes users will need to install extensions and fewer will need to author new ones.
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FinalizerLINK
Finalizers are namespaced keys that tell Kubernetes to wait until specific conditions are met before it fully deletes resources marked for deletion. Finalizers alert controllers to clean up resources the deleted object owned.
[+]When you tell Kubernetes to delete an object that has finalizers specified for it, the Kubernetes API marks the object for deletion, putting it into a read-only state. The target object remains in a terminating state while the control plane, or other components, take the actions defined by the finalizers. After these actions are complete, the controller removes the relevant finalizers from the target object. When the
metadata.finalizers
field is empty, Kubernetes considers the deletion complete.You can use finalizers to control garbage collection of resources. For example, you can define a finalizer to clean up related resources or infrastructure before the controller deletes the target resource.
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FlexVolumeLINK
FlexVolume is an interface for creating out-of-tree volume plugins. The Container Storage Interface is a newer interface which addresses several problems with FlexVolumes.
[+]FlexVolumes enable users to write their own drivers and add support for their volumes in Kubernetes. FlexVolume driver binaries and dependencies must be installed on host machines. This requires root access. The Storage SIG suggests implementing a CSI driver if possible since it addresses the limitations with FlexVolumes.
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Garbage CollectionLINK
Garbage collection is a collective term for the various mechanisms Kubernetes uses to clean up cluster resources.
[+]Kubernetes uses garbage collection to clean up resources like unused containers and images, failed Pods, objects owned by the targeted resource, completed Jobs, and resources that have expired or failed.
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Gerenciador de controle de nuvemLINK
Um componente da camada de gerenciamento do Kubernetes que incorpora a lógica de controle específica da nuvem. O gerenciador de controle de nuvem permite que você vincule seu cluster na API do seu provedor de nuvem, e separar os componentes que interagem com essa plataforma de nuvem a partir de componentes que apenas interagem com seu cluster.
[+]Desassociando a lógica de interoperabilidade entre o Kubernetes e a infraestrutura de nuvem subjacente, o componente gerenciador de controle de nuvem permite que os provedores de nuvem desenvolvam e disponibilizem recursos em um ritmo diferente em comparação com o projeto principal do Kubernetes.
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Helm ChartLINK
A package of pre-configured Kubernetes resources that can be managed with the Helm tool.
[+]Charts provide a reproducible way of creating and sharing Kubernetes applications. A single chart can be used to deploy something simple, like a memcached Pod, or something complex, like a full web app stack with HTTP servers, databases, caches, and so on.
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Horizontal Pod AutoscalerLINKTambém conhecido como:HPA
An API resource that automatically scales the number of Pod replicas based on targeted CPU utilization or custom metric targets.
[+]HPA is typically used with ReplicationControllers, Deployments, or ReplicaSets. It cannot be applied to objects that cannot be scaled, for example DaemonSets.
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HostAliasesLINK
A HostAliases is a mapping between the IP address and hostname to be injected into a Pod's hosts file.
[+]HostAliases is an optional list of hostnames and IP addresses that will be injected into the Pod's hosts file if specified. This is only valid for non-hostNetwork Pods.
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ImageLINK
Stored instance of a Container that holds a set of software needed to run an application.
[+]A way of packaging software that allows it to be stored in a container registry, pulled to a local system, and run as an application. Meta data is included in the image that can indicate what executable to run, who built it, and other information.
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Init ContainerLINK
One or more initialization containers that must run to completion before any app containers run.
[+]Initialization (init) containers are like regular app containers, with one difference: init containers must run to completion before any app containers can start. Init containers run in series: each init container must run to completion before the next init container begins.
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IstioLINK
An open platform (not Kubernetes-specific) that provides a uniform way to integrate microservices, manage traffic flow, enforce policies, and aggregate telemetry data.
[+]Adding Istio does not require changing application code. It is a layer of infrastructure between a service and the network, which when combined with service deployments, is commonly referred to as a service mesh. Istio's control plane abstracts away the underlying cluster management platform, which may be Kubernetes, Mesosphere, etc.
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KerberosLINK[+]
Kerberos é um protocolo de rede que usa criptografia de chave secreta para autenticar aplicativos cliente-servidor. O Kerberos solicita um tíquete criptografado por meio de uma sequência de servidor autenticada para usar os serviços.
Kerberos foi desenvolvido pelo Project Athena - um projeto conjunto entre o Massachusetts Institute of Technology (MIT), Digital Equipment Corporation e IBM que funcionou entre 1983 e 1991.
Um servidor de autenticação usa um tíquete Kerberos para conceder acesso ao servidor e, em seguida, cria uma chave de sessão com base na senha do solicitante e outro valor aleatório. O tíquete de concessão de tíquete (TGT) é enviado ao servidor de concessão de tíquete (TGS), que é necessário para usar o mesmo servidor de autenticação.
O solicitante recebe uma chave TGS criptografada com um registro de data e hora e um tíquete de serviço, que é retornado ao solicitante e descriptografado. O solicitante envia ao TGS essas informações e encaminha a chave criptografada ao servidor para obter o serviço desejado. Se todas as ações forem tratadas corretamente, o servidor aceita o tíquete e realiza o atendimento ao usuário desejado, que deve descriptografar a chave, verificar a data e hora e entrar em contato com o centro de distribuição para obter as chaves de sessão. Essa chave de sessão é enviada ao solicitante, que descriptografa o tíquete.
Se as chaves e o carimbo de data / hora forem válidos, a comunicação cliente-servidor continuará. O tíquete TGS tem carimbo de data / hora, o que permite solicitações simultâneas dentro do período de tempo alocado.
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KeystoneLINK[+]
Keystone é o serviço de identidade usado pelo OpenStack para autenticação (authN) e autorização de alto nível (authZ). Atualmente, ele oferece suporte a authN com base em token e autorização de serviço do usuário. Recentemente, foi reprojetado para permitir a expansão para oferecer suporte a serviços externos de proxy e mecanismos AuthN / AuthZ, como oAuth, SAML e openID em versões futuras.
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KopsLINK
A CLI tool that helps you create, destroy, upgrade and maintain production-grade, highly available, Kubernetes clusters.
[+]Note: kops has general availability support only for AWS. Support for using kops with GCE and VMware vSphere are in alpha.kops
provisions your cluster with:- Fully automated installation
- DNS-based cluster identification
- Self-healing: everything runs in Auto-Scaling Groups
- Limited OS support (Debian preferred, Ubuntu 16.04 supported, early support for CentOS & RHEL)
- High availability (HA) support
- The ability to directly provision, or to generate Terraform manifests
You can also build your own cluster using Kubeadm as a building block.
kops
builds on the kubeadm work. -
kube-controller-managerLINK
Componente da camada de gerenciamento que executa os processos de controlador.
[+]Logicamente, cada controlador está em um processo separado, mas para reduzir a complexidade, eles todos são compilados num único binário e executam em um processo único.
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kube-proxyLINK
kube-proxy é um proxy de rede executado em cada nó no seu cluster, implementando parte do conceito de serviço do Kubernetes.
[+]kube-proxy mantém regras de rede nos nós. Estas regras de rede permitem a comunicação de rede com seus pods a partir de sessões de rede dentro ou fora de seu cluster.
kube-proxy usa a camada de filtragem de pacotes do sistema operacional se houver uma e estiver disponível. Caso contrário, o kube-proxy encaminha o tráfego ele mesmo.
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kube-schedulerLINK
Componente da camada de gerenciamento que observa os pods recém-criados sem nenhum nó atribuído, e seleciona um nó para executá-los.
[+]Os fatores levados em consideração para as decisões de agendamento incluem: requisitos de recursos individuais e coletivos, hardware/software/política de restrições, especificações de afinidade e antiafinidade, localidade de dados, interferência entre cargas de trabalho, e prazos.
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KubeadmLINK
A tool for quickly installing Kubernetes and setting up a secure cluster.
[+]You can use kubeadm to install both the control plane and the worker node components.
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KubectlLINK
A command line tool for communicating with a Kubernetes API server.
[+]You can use kubectl to create, inspect, update, and delete Kubernetes objects.
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KubeletLINK
Um agente que é executado em cada node no cluster. Ele garante que os contêineres estejam sendo executados em um Pod.
[+]O kubelet utiliza um conjunto de PodSpecs que são fornecidos por vários mecanismos e garante que os contêineres descritos nesses PodSpecs estejam funcionando corretamente. O kubelet não gerencia contêineres que não foram criados pelo Kubernetes.
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Kubernetes APILINK
The application that serves Kubernetes functionality through a RESTful interface and stores the state of the cluster.
[+]Kubernetes resources and "records of intent" are all stored as API objects, and modified via RESTful calls to the API. The API allows configuration to be managed in a declarative way. Users can interact with the Kubernetes API directly, or via tools like
kubectl
. The core Kubernetes API is flexible and can also be extended to support custom resources. -
LDAPLINK[+]
Abreviatura para "Lightweight Directory Access Protocol". Se você deseja disponibilizar informações de diretório na Internet, esta é a maneira de fazê-lo. O LDAP é uma versão simplificada de um padrão de diretório anterior denominado X.500. O que torna o LDAP tão útil é que ele funciona muito bem em redes TCP / IP (ao contrário do X.500), de modo que as informações podem ser acessadas por meio do LDAP por qualquer pessoa com uma conexão à Internet. Também é um protocolo aberto, o que significa que os diretórios podem ser armazenados em qualquer tipo de máquina (por exemplo, Windows 2000, Red Hat Linux, Mac OS X).
Para dar uma ideia de como um diretório LDAP é organizado, aqui estão os diferentes níveis de uma hierarquia de árvore LDAP simples:
O diretório raiz Países Organizações Divisões, departamentos, etc. Indivíduos Recursos individuais, como arquivos e impressoras. A maior parte da conectividade LDAP é feita nos bastidores, então o usuário típico provavelmente não notará ao navegar na web. No entanto, é uma boa tecnologia para se conhecer. Se nada mais, é outro termo para impressionar seus pais.
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LimitRangeLINK
Provides constraints to limit resource consumption per Containers or Pods in a namespace.
[+]LimitRange limits the quantity of objects that can be created by type, as well as the amount of compute resources that may be requested/consumed by individual Containers or Pods in a namespace.
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Managed ServiceLINK
A software offering maintained by a third-party provider.
[+]Some examples of Managed Services are AWS EC2, Azure SQL Database, and GCP Pub/Sub, but they can be any software offering that can be used by an application. Service Catalog provides a way to list, provision, and bind with Managed Services offered by Service Brokers.
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MasterLINK
Legacy term, used as synonym for nodes hosting the control plane.
[+]The term is still being used by some provisioning tools, such as kubeadm, and managed services, to label nodes with
kubernetes.io/role
and control placement of control plane pods. -
MemberLINK
A continuously active contributor in the K8s community.
[+]Members can have issues and PRs assigned to them and participate in special interest groups (SIGs) through GitHub teams. Pre-submit tests are automatically run for members' PRs. A member is expected to remain an active contributor to the community.
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MinikubeLINK
A tool for running Kubernetes locally.
[+]Minikube runs a single-node cluster inside a VM on your computer. You can use Minikube to try Kubernetes in a learning environment.
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Mirror PodLINK
A pod object that a kubelet uses to represent a static pod
[+]When the kubelet finds a static pod in its configuration, it automatically tries to create a Pod object on the Kubernetes API server for it. This means that the pod will be visible on the API server, but cannot be controlled from there.
(For example, removing a mirror pod will not stop the kubelet daemon from running it).
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NamespaceLINK
An abstraction used by Kubernetes to support multiple virtual clusters on the same physical cluster.
[+]Namespaces are used to organize objects in a cluster and provide a way to divide cluster resources. Names of resources need to be unique within a namespace, but not across namespaces.
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Network PolicyLINK
A specification of how groups of Pods are allowed to communicate with each other and with other network endpoints.
[+]Network Policies help you declaratively configure which Pods are allowed to connect to each other, which namespaces are allowed to communicate, and more specifically which port numbers to enforce each policy on.
NetworkPolicy
resources use labels to select Pods and define rules which specify what traffic is allowed to the selected Pods. Network Policies are implemented by a supported network plugin provided by a network provider. Be aware that creating a network resource without a controller to implement it will have no effect. -
Node-pressure evictionLINKTambém conhecido como:kubelet eviction
Node-pressure eviction is the process by which the kubelet proactively terminates pods to reclaim resources on nodes.
[+]The kubelet monitors resources like CPU, memory, disk space, and filesystem inodes on your cluster's nodes. When one or more of these resources reach specific consumption levels, the kubelet can proactively fail one or more pods on the node to reclaim resources and prevent starvation.
Node-pressure eviction is not the same as API-initiated eviction.
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NóLINK
Um Nó é uma máquina de trabalho no Kubernetes.
[+]Um Nó pode ser uma máquina virtual ou física, dependendo do cluster. Possui daemons ou serviços locais necessários para executar Pods e é gerenciado pelo ambiente de gerenciamento. Os daemons em um Node incluem kubelet, kube-proxy e um contêiner runtime implementando o CRI como por exemplo o Docker.
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ObjectLINK
An entity in the Kubernetes system. The Kubernetes API uses these entities to represent the state of your cluster.
[+]A Kubernetes object is typically a “record of intent”—once you create the object, the Kubernetes control plane works constantly to ensure that the item it represents actually exists. By creating an object, you're effectively telling the Kubernetes system what you want that part of your cluster's workload to look like; this is your cluster's desired state.
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Operator patternLINK
The operator pattern is a system design that links a Controller to one or more custom resources.
[+]You can extend Kubernetes by adding controllers to your cluster, beyond the built-in controllers that come as part of Kubernetes itself.
If a running application acts as a controller and has API access to carry out tasks against a custom resource that's defined in the control plane, that's an example of the Operator pattern.
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Persistent VolumeLINK
An API object that represents a piece of storage in the cluster. Available as a general, pluggable resource that persists beyond the lifecycle of any individual Pod.
[+]PersistentVolumes (PVs) provide an API that abstracts details of how storage is provided from how it is consumed. PVs are used directly in scenarios where storage can be created ahead of time (static provisioning). For scenarios that require on-demand storage (dynamic provisioning), PersistentVolumeClaims (PVCs) are used instead.
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Persistent Volume ClaimLINK
Claims storage resources defined in a PersistentVolume so that it can be mounted as a volume in a container.
[+]Specifies the amount of storage, how the storage will be accessed (read-only, read-write and/or exclusive) and how it is reclaimed (retained, recycled or deleted). Details of the storage itself are described in the PersistentVolume object.
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Platform DeveloperLINK
A person who customizes the Kubernetes platform to fit the needs of their project.
[+]A platform developer may, for example, use Custom Resources or Extend the Kubernetes API with the aggregation layer to add functionality to their instance of Kubernetes, specifically for their application. Some Platform Developers are also contributors and develop extensions which are contributed to the Kubernetes community. Others develop closed-source commercial or site-specific extensions.
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PodLINK
O menor e mais simples objeto Kubernetes. Um Pod representa um conjunto de contêineres em execução no seu cluster.
[+]Um Pod é normalmente configurado para executar um único contêiner primário. Ele também pode executar contêineres opcionais que adicionam recursos adicionais, como registro em log. Os pods são geralmente gerenciados por um Deployment.
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Pod DisruptionLINKPod disruption is the process by which Pods on Nodes are terminated either voluntarily or involuntarily. Voluntary disruptions are started intentionally by application owners or cluster administrators. Involuntary disruptions are unintentional and can be triggered by unavoidable issues like Nodes running out of resources, or by accidental deletions. [+]
Pod disruption is the process by which Pods on Nodes are terminated either voluntarily or involuntarily.
Voluntary disruptions are started intentionally by application owners or cluster administrators. Involuntary disruptions are unintentional and can be triggered by unavoidable issues like Nodes running out of resources, or by accidental deletions.
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Pod Disruption BudgetLINKTambém conhecido como:PDB
A Pod Disruption Budget allows an application owner to create an object for a replicated application, that ensures a certain number or percentage of Pods with an assigned label will not be voluntarily evicted at any point in time. PDBs cannot prevent an involuntary disruption, but will count against the budget. [+]A Pod Disruption Budget allows an application owner to create an object for a replicated application, that ensures a certain number or percentage of Pods with an assigned label will not be voluntarily evicted at any point in time. PDBs cannot prevent an involuntary disruption, but will count against the budget.
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Pod LifecycleLINK
The sequence of states through which a Pod passes during its lifetime.
[+]The Pod Lifecycle is defined by the states or phases of a Pod. There are five possible Pod phases: Pending, Running, Succeeded, Failed, and Unknown. A high-level description of the Pod state is summarized in the PodStatus
phase
field. -
Pod PriorityLINK
Pod Priority indicates the importance of a Pod relative to other Pods.
[+]Pod Priority gives the ability to set scheduling priority of a Pod to be higher and lower than other Pods — an important feature for production clusters workload.
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Pod Security PolicyLINK
Enables fine-grained authorization of Pod creation and updates.
[+]A cluster-level resource that controls security sensitive aspects of the Pod specification. The
PodSecurityPolicy
objects define a set of conditions that a Pod must run with in order to be accepted into the system, as well as defaults for the related fields. Pod Security Policy control is implemented as an optional admission controller. -
ProxyLINK
In computing, a proxy is a server that acts as an intermediary for a remote service.
[+]A client interacts with the proxy; the proxy copies the client's data to the actual server; the actual server replies to the proxy; the proxy sends the actual server's reply to the client.
kube-proxy is a network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept.
You can run kube-proxy as a plain userland proxy service. If your operating system supports it, you can instead run kube-proxy in a hybrid mode that achieves the same overall effect using less system resources.
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QoS ClassLINK
QoS Class (Quality of Service Class) provides a way for Kubernetes to classify Pods within the cluster into several classes and make decisions about scheduling and eviction.
[+]QoS Class of a Pod is set at creation time based on its compute resources requests and limits settings. QoS classes are used to make decisions about Pods scheduling and eviction. Kubernetes can assign one of the following QoS classes to a Pod:
Guaranteed
,Burstable
orBestEffort
. -
QuantityLINK
A whole-number representation of small or large numbers using SI suffixes.
[+]Quantities are representations of small or large numbers using a compact, whole-number notation with SI suffixes. Fractional numbers are represented using milli units, while large numbers can be represented using kilo, mega, or giga units.
For instance, the number
1.5
is represented as1500m
, while the number1000
can be represented as1k
, and1000000
as1M
. You can also specify binary-notation suffixes; the number 2048 can be written as2Ki
.The accepted decimal (power-of-10) units are
m
(milli),k
(kilo, intentionally lowercase),M
(mega),G
(giga),T
(tera),P
(peta),E
(exa).The accepted binary (power-of-2) units are
Ki
(kibi),Mi
(mebi),Gi
(gibi),Ti
(tebi),Pi
(pebi),Ei
(exbi). -
RBAC (Role-Based Access Control)LINK
Manages authorization decisions, allowing admins to dynamically configure access policies through the Kubernetes API.
[+]RBAC utilizes roles, which contain permission rules, and role bindings, which grant the permissions defined in a role to a set of users.
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ReplicaSetLINK
A ReplicaSet (aims to) maintain a set of replica Pods running at any given time.
[+]Workload objects such as Deployment make use of ReplicaSets to ensure that the configured number of Pods are running in your cluster, based on the spec of that ReplicaSet.
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ReplicationControllerLINK
A workload resource that manages a replicated application, ensuring that a specific number of instances of a Pod are running.
[+]The control plane ensures that the defined number of Pods are running, even if some Pods fail, if you delete Pods manually, or if too many are started by mistake.
Note: ReplicationController is deprecated. See Deployment, which is similar. -
SAMLLINK[+]
SAML significa Linguagem de Marcação para Asserção de Segurança. É um padrão aberto baseado em XML para transferência de dados de identidade entre duas partes: um provedor de identidade (IdP) e um provedor de serviços (SP).
Provedor de identidade - executa autenticação e passa a identidade do usuário e o nível de autorização para o provedor de serviços.
Provedor de serviços - confia no provedor de identidade e autoriza o usuário fornecido a acessar o recurso solicitado.
A autenticação de logon único SAML normalmente envolve um provedor de serviços e um provedor de identidade. O fluxo do processo geralmente envolve os estágios de estabelecimento de confiança e fluxo de autenticação.
Considere este exemplo:
Nosso provedor de identidade é Auth0 Nosso provedor de serviços é um serviço fictício, Zagadat Nota: O provedor de identidade pode ser qualquer plataforma de gerenciamento de identidade.
Agora, um usuário está tentando obter acesso ao Zagadat usando a autenticação SAML.
Este é o fluxo do processo:
O usuário tenta fazer login no Zagadat a partir de um navegador. O Zagadat responde gerando uma solicitação SAML.
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SecretLINK
Stores sensitive information, such as passwords, OAuth tokens, and ssh keys.
[+]Allows for more control over how sensitive information is used and reduces the risk of accidental exposure, including encryption at rest. A Pod references the secret as a file in a volume mount or by the kubelet pulling images for a pod. Secrets are great for confidential data and ConfigMaps for non-confidential data.
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Security ContextLINK
The
[+]securityContext
field defines privilege and access control settings for a Pod or container.In a
securityContext
, you can define: the user that processes run as, the group that processes run as, and privilege settings. You can also configure security policies (for example: SELinux, AppArmor or seccomp).The
PodSpec.securityContext
setting applies to all containers in a Pod. -
ServiceLINK
An abstract way to expose an application running on a set of Pods as a network service.
[+]The set of Pods targeted by a Service is (usually) determined by a selector. If more Pods are added or removed, the set of Pods matching the selector will change. The Service makes sure that network traffic can be directed to the current set of Pods for the workload.
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Service BrokerLINK
An endpoint for a set of Managed Services offered and maintained by a third-party.
[+]Service Brokers implement the Open Service Broker API spec and provide a standard interface for applications to use their Managed Services. Service Catalog provides a way to list, provision, and bind with Managed Services offered by Service Brokers.
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Service CatalogLINK
An extension API that enables applications running in Kubernetes clusters to easily use external managed software offerings, such as a datastore service offered by a cloud provider.
[+]It provides a way to list, provision, and bind with external Managed Services from Service Brokers without needing detailed knowledge about how those services are created or managed.
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ServiceAccountLINK
Provides an identity for processes that run in a Pod.
[+]When processes inside Pods access the cluster, they are authenticated by the API server as a particular service account, for example,
default
. When you create a Pod, if you do not specify a service account, it is automatically assigned the default service account in the same Namespace. -
shuffle shardingLINK
A technique for assigning requests to queues that provides better isolation than hashing modulo the number of queues.
[+]We are often concerned with insulating different flows of requests from each other, so that a high-intensity flow does not crowd out low-intensity flows. A simple way to put requests into queues is to hash some characteristics of the request, modulo the number of queues, to get the index of the queue to use. The hash function uses as input characteristics of the request that align with flows. For example, in the Internet this is often the 5-tuple of source and destination address, protocol, and source and destination port.
That simple hash-based scheme has the property that any high-intensity flow will crowd out all the low-intensity flows that hash to the same queue. Providing good insulation for a large number of flows requires a large number of queues, which is problematic. Shuffle sharding is a more nimble technique that can do a better job of insulating the low-intensity flows from the high-intensity flows. The terminology of shuffle sharding uses the metaphor of dealing a hand from a deck of cards; each queue is a metaphorical card. The shuffle sharding technique starts with hashing the flow-identifying characteristics of the request, to produce a hash value with dozens or more of bits. Then the hash value is used as a source of entropy to shuffle the deck and deal a hand of cards (queues). All the dealt queues are examined, and the request is put into one of the examined queues with the shortest length. With a modest hand size, it does not cost much to examine all the dealt cards and a given low-intensity flow has a good chance to dodge the effects of a given high-intensity flow. With a large hand size it is expensive to examine the dealt queues and more difficult for the low-intensity flows to dodge the collective effects of a set of high-intensity flows. Thus, the hand size should be chosen judiciously.
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SIG (special interest group)LINK
Community members who collectively manage an ongoing piece or aspect of the larger Kubernetes open source project.
[+]Members within a SIG have a shared interest in advancing a specific area, such as architecture, API machinery, or documentation. SIGs must follow the SIG governance guidelines, but can have their own contribution policy and channels of communication.
For more information, see the kubernetes/community repo and the current list of SIGs and Working Groups.
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StatefulSetLINK
Manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods.
[+]Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. Unlike a Deployment, a StatefulSet maintains a sticky identity for each of their Pods. These pods are created from the same spec, but are not interchangeable: each has a persistent identifier that it maintains across any rescheduling.
If you want to use storage volumes to provide persistence for your workload, you can use a StatefulSet as part of the solution. Although individual Pods in a StatefulSet are susceptible to failure, the persistent Pod identifiers make it easier to match existing volumes to the new Pods that replace any that have failed.
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Storage ClassLINK
A StorageClass provides a way for administrators to describe different available storage types.
[+]StorageClasses can map to quality-of-service levels, backup policies, or to arbitrary policies determined by cluster administrators. Each StorageClass contains the fields
provisioner
,parameters
, andreclaimPolicy
, which are used when a Persistent Volume belonging to the class needs to be dynamically provisioned. Users can request a particular class using the name of a StorageClass object. -
sysctlLINK
[+]sysctl
is a semi-standardized interface for reading or changing the attributes of the running Unix kernel.On Unix-like systems,
sysctl
is both the name of the tool that administrators use to view and modify these settings, and also the system call that the tool uses.Container runtimes and network plugins may rely on
sysctl
values being set a certain way. -
TaintLINK
A core object consisting of three required properties: key, value, and effect. Taints prevent the scheduling of Pods on nodes or node groups.
[+]Taints and tolerations work together to ensure that pods are not scheduled onto inappropriate nodes. One or more taints are applied to a node. A node should only schedule a Pod with the matching tolerations for the configured taints.
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TLS Common NameLINK[+]
O nome comum é normalmente composto de Host + Nome de domínio e será semelhante a www.seusite.com ou seusite.com. Os certificados de servidor SSL são específicos para o nome comum para o qual foram emitidos no nível do host.
O nome comum deve ser igual ao endereço da Web que você acessará ao se conectar a um site seguro. Por exemplo, um certificado de servidor SSL para o domínio domínio.com receberá um aviso do navegador se o acesso a um site chamado www.domain.com ou secure.domain.com, pois www.domain.com e secure.domain.com são diferentes de dominio.com. Você precisaria criar um CSR para o nome comum correto.
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UIDLINKUm identificador exclusivo (UID) é uma sequência numérica ou alfanumérica associada a uma única entidade em um determinado sistema. Os UIDs tornam possível endereçar essa entidade para que ela possa ser acessada e interagida. Cada usuário é identificado no sistema por seu UID e os nomes de usuário geralmente são usados apenas como uma interface para humanos. [+]
Um identificador exclusivo (UID) é uma sequência numérica ou alfanumérica associada a uma única entidade em um determinado sistema. Os UIDs tornam possível endereçar essa entidade para que ela possa ser acessada e interagida. Cada usuário é identificado no sistema por seu UID e os nomes de usuário geralmente são usados apenas como uma interface para humanos.
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Upstream (disambiguation)LINK
May refer to: core Kubernetes or the source repo from which a repo was forked.
[+]- In the Kubernetes Community: Conversations often use upstream to mean the core Kubernetes codebase, which the general ecosystem, other code, or third-party tools rely upon. For example, community members may suggest that a feature is moved upstream so that it is in the core codebase instead of in a plugin or third-party tool.
- In GitHub or git: The convention is to refer to a source repo as upstream, whereas the forked repo is considered downstream.
-
user namespaceLINK
A kernel feature to emulate root. Used for "rootless containers".
[+]User namespaces are a Linux kernel feature that allows a non-root user to emulate superuser ("root") privileges, for example in order to run containers without being a superuser outside the container.
User namespace is effective for mitigating damage of potential container break-out attacks.
In the context of user namespaces, the namespace is a Linux kernel feature, and not a namespace in the Kubernetes sense of the term.
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UsernameLINK
Um nome de usuário é um nome que identifica exclusivamente alguém em um sistema de computador. Por exemplo, um computador pode ser configurado com várias contas, com nomes de usuário diferentes para cada conta. Muitos sites permitem que os usuários escolham um nome de usuário para que possam personalizar suas configurações ou configurar uma conta online. Por exemplo, seu banco pode permitir que você escolha um nome de usuário para acessar suas informações bancárias. Você pode precisar escolher um nome de usuário para postar mensagens em um determinado quadro de mensagens na web. Os serviços de e-mail, como o Hotmail, exigem que os usuários escolham um nome de usuário para usar o serviço.
[+]Um nome de usuário geralmente é pareado com uma senha. Essa combinação de nome de usuário / senha é conhecida como login e geralmente é necessária para que os usuários façam login em sites. Por exemplo, para acessar seu e-mail pela Web, é necessário inserir seu nome de usuário e senha. Depois de fazer o login, seu nome de usuário pode aparecer na tela, mas sua senha é mantida em segredo. Ao manter sua senha privada, as pessoas podem criar contas seguras para vários sites. A maioria dos nomes de usuário pode conter letras e números, mas não espaços. Quando você escolhe um nome de usuário para uma conta de e-mail, a parte antes de "@" é o seu nome de usuário.
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VolumeLINK
A directory containing data, accessible to the containers in a Pod.
[+]A Kubernetes volume lives as long as the Pod that encloses it. Consequently, a volume outlives any containers that run within the Pod, and data in the volume is preserved across container restarts.
See storage for more information.
-
Volume PluginLINK
A Volume Plugin enables integration of storage within a Pod.
[+]A Volume Plugin lets you attach and mount storage volumes for use by a Pod. Volume plugins can be in tree or out of tree. In tree plugins are part of the Kubernetes code repository and follow its release cycle. Out of tree plugins are developed independently.
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WG (working group)LINK
Facilitates the discussion and/or implementation of a short-lived, narrow, or decoupled project for a committee, SIG, or cross-SIG effort.
[+]Working groups are a way of organizing people to accomplish a discrete task.
For more information, see the kubernetes/community repo and the current list of SIGs and working groups.
-
WorkloadLINK
A workload is an application running on Kubernetes.
[+]Various core objects that represent different types or parts of a workload include the DaemonSet, Deployment, Job, ReplicaSet, and StatefulSet objects.
For example, a workload that has a web server and a database might run the database in one StatefulSet and the web server in a Deployment.
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