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87-780: The name Kubernetes originates from the Greek κυβερνήτης (kubernḗtēs), meaning governor, ' helmsman ' or 'pilot'. Kubernetes is often abbreviated as K8s , counting the eight letters between the K and the s (a numeronym ). Kubernetes assembles one or more computers, either virtual machines or bare metal , into a cluster which can run workloads in containers. It works with various container runtimes, such as containerd and CRI-O . Its suitability for running and managing workloads of all sizes and styles has led to its widespread adoption in clouds and data centers. There are multiple distributions of this platform – from independent software vendors (ISVs) as well as hosted-on-cloud offerings from all

174-414: A ReplicaSet, serves the same purpose and behaves similarly to a ReplicaSet, which is to ensure that there will always be a specified number of pod replicas as desired. The ReplicationController workload was the predecessor of a ReplicaSet, but was eventually deprecated in favor of ReplicaSet to make use of set-based label selectors. Deployments are a higher-level management mechanism for ReplicaSets. While

261-570: A basis for coinages: anthropology , photography , telephony , isomer , biomechanics , cinematography , etc. Together with Latin words , they form the foundation of international scientific and technical vocabulary ; for example, all words ending in -logy ('discourse'). There are many English words of Greek origin . Greek is an independent branch of the Indo-European language family. The ancient language most closely related to it may be ancient Macedonian , which, by most accounts,

348-481: A disease that is due to a root cause of illness Christian Science practitioner#Primary class instruction See also [ edit ] Binary (disambiguation) Primary group (disambiguation) Second (disambiguation) Unary (disambiguation) All pages with titles beginning with Primary All pages with titles containing Primary Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

435-552: A fairly stable set of consonantal contrasts . The main phonological changes occurred during the Hellenistic and Roman period (see Koine Greek phonology for details): In all its stages, the morphology of Greek shows an extensive set of productive derivational affixes , a limited but productive system of compounding and a rich inflectional system. Although its morphological categories have been fairly stable over time, morphological changes are present throughout, particularly in

522-556: A faster, more convenient cursive writing style with the use of ink and quill . The Greek alphabet consists of 24 letters, each with an uppercase ( majuscule ) and lowercase ( minuscule ) form. The letter sigma has an additional lowercase form (ς) used in the final position of a word: In addition to the letters, the Greek alphabet features a number of diacritical signs : three different accent marks ( acute , grave , and circumflex ), originally denoting different shapes of pitch accent on

609-531: A foreign language. It is also often stated that the historical changes have been relatively slight compared with some other languages. According to one estimation, " Homeric Greek is probably closer to Demotic than 12-century Middle English is to modern spoken English ". Greek is spoken today by at least 13 million people, principally in Greece and Cyprus along with a sizable Greek-speaking minority in Albania near

696-499: A loose coupling within the infrastructure. For example, if an application's pods have labels for a system tier (with values such as frontend , backend , for example) and a release_track (with values such as canary , production , for example), then an operation on all of backend and canary nodes can use a label selector, such as: tier=backend AND release_track=canary Just like labels, field selectors also let one select Kubernetes resources. Unlike labels,

783-492: A prime number Politics [ edit ] Primary elections or primaries, elections held to determine which candidates will run for an upcoming general election Primary vote, the total of first-preference votes in the Australian electoral system Science and mechanics [ edit ] Primary (astronomy) , the larger of two co-orbiting bodies Primary (chemistry) , term used in organic chemistry Primary,

870-468: A service can also be exposed outside a cluster (e.g., for clients to reach front-end pods). Filesystems in the Kubernetes container provide ephemeral storage , by default. This means that a restart of the pod will wipe out any data on such containers, and therefore, this form of storage is quite limiting in anything but trivial applications. A Kubernetes volume provides persistent storage that exists for

957-579: A set of building blocks ("primitives") that collectively provide mechanisms that deploy, maintain, and scale applications based on CPU , memory or custom metrics. Kubernetes is loosely coupled and extensible to meet the needs of different workloads. The internal components as well as extensions and containers that run on Kubernetes rely on the Kubernetes API. The platform exerts its control over compute and storage resources by defining resources as objects, which can then be managed as such. Kubernetes follows

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1044-422: A single cluster. As such, scheduler plug-ins may be developed and installed as in-process extensions to the native vanilla scheduler by running it as a separate scheduler, as long as they conform to the Kubernetes scheduling framework. This allows cluster administrators to extend or modify the behavior of the default Kubernetes scheduler according to their needs. A controller is a reconciliation loop that drives

1131-422: A stable IP address and DNS name to the service, and load balances traffic in a round-robin manner to network connections of that IP address among the pods matching the selector (even as failures cause the pods to move from machine to machine). By default a service is exposed inside a cluster (e.g., back end pods might be grouped into a service, with requests from the front-end pods load-balanced among them), but

1218-420: A strong authentication method, network separation, each its own process, that can run both on a single master node or on multiple masters supporting high-availability clusters . The various components of the Kubernetes control plane are as follows. Etcd is a persistent, lightweight, distributed, key-value data store (originally developed for Container Linux ). It reliably stores the configuration data of

1305-458: A transformer Primary feathers , flight feathers attached to the manus ("hand") in the wings of birds Primary color Other uses [ edit ] Primary (LDS Church) , a children's Sunday School organization Primary (musician) (born 1983), South Korean Primary data (or raw data), a term for data collected from a source Primary Flight Training , in the U.S. Navy Primary source , original materials Primary disease ,

1392-408: Is a pod , which consists of one or more containers that are guaranteed to be co-located on the same node. Each pod in Kubernetes is assigned a unique IP address within the cluster, allowing applications to use ports without the risk of conflict. Within the pod, all containers can reference each other. A container resides inside a pod. The container is the lowest level of a micro-service, which holds

1479-462: Is a machine where containers (workloads) are deployed. Every node in the cluster must run a container runtime , as well as the below-mentioned components, for communication with the primary network configuration of these containers. kubelet is responsible for the running state of each node, ensuring that all containers on the node are healthy. It takes care of starting, stopping, and maintaining application containers organized into pods as directed by

1566-766: Is also found in Bulgaria near the Greek-Bulgarian border. Greek is also spoken worldwide by the sizable Greek diaspora which has notable communities in the United States , Australia , Canada , South Africa , Chile , Brazil , Argentina , Russia , Ukraine , the United Kingdom , and throughout the European Union , especially in Germany . Historically, significant Greek-speaking communities and regions were found throughout

1653-742: Is an Indo-European language, constituting an independent Hellenic branch within the Indo-European language family. It is native to Greece , Cyprus , Italy (in Calabria and Salento ), southern Albania , and other regions of the Balkans , Caucasus , the Black Sea coast, Asia Minor , and the Eastern Mediterranean . It has the longest documented history of any Indo-European language, spanning at least 3,400 years of written records. Its writing system

1740-474: Is an Indo-European language, but also includes a number of borrowings from the languages of the populations that inhabited Greece before the arrival of Proto-Greeks, some documented in Mycenaean texts ; they include a large number of Greek toponyms . The form and meaning of many words have changed. Loanwords (words of foreign origin) have entered the language, mainly from Latin, Venetian , and Turkish . During

1827-612: Is an implementation of a network proxy and a load balancer , and it supports the service abstraction along with the other networking operations. It is responsible for routing traffic to the appropriate container based on IP and port number of the incoming request. In Kubernetes, namespaces are utilized to segregate the resources it handles into distinct and non-intersecting collections. They are intended for use in environments with many users spread across multiple teams, or projects, or even separating environments like development, test, and production. The basic scheduling unit in Kubernetes

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1914-583: Is deciding where to store and manage configuration information, some of which may contain sensitive data. Configuration data can be anything as fine-grained as individual properties, or coarse-grained information like entire configuration files such as JSON or XML documents. Kubernetes provides two closely related mechanisms to deal with this need, known as ConfigMaps and Secrets , both of which allow for configuration changes to be made without requiring an application rebuild. The data from ConfigMaps and Secrets will be made available to every single instance of

2001-411: Is not scheduled in excess of available resources. For this purpose, the scheduler must know the resource requirements, resource availability, and other user-provided constraints or policy directives such as quality-of-service, affinity/anti-affinity requirements, and data locality. The scheduler's role is to match resource "supply" to workload "demand". Kubernetes allows running multiple schedulers within

2088-510: Is protected and promoted officially as a regional and minority language in Armenia, Hungary , Romania, and Ukraine. It is recognized as a minority language and protected in Turkey by the 1923 Treaty of Lausanne . The phonology , morphology , syntax , and vocabulary of the language show both conservative and innovative tendencies across the entire attestation of the language from the ancient to

2175-773: Is sometimes called aljamiado , as when Romance languages are written in the Arabic alphabet. Article 1 of the Universal Declaration of Human Rights in Greek: Transcription of the example text into Latin alphabet : Article 1 of the Universal Declaration of Human Rights in English: Proto-Greek Mycenaean Ancient Koine Medieval Modern Primary From Misplaced Pages,

2262-471: Is spoken by at least 13.5 million people today in Greece, Cyprus, Italy, Albania, Turkey , and the many other countries of the Greek diaspora . Greek roots have been widely used for centuries and continue to be widely used to coin new words in other languages; Greek and Latin are the predominant sources of international scientific vocabulary . Greek has been spoken in the Balkan peninsula since around

2349-758: Is still used internationally for the writing of Ancient Greek . In Greek, the question mark is written as the English semicolon, while the functions of the colon and semicolon are performed by a raised point (•), known as the ano teleia ( άνω τελεία ). In Greek the comma also functions as a silent letter in a handful of Greek words, principally distinguishing ό,τι ( ó,ti , 'whatever') from ότι ( óti , 'that'). Ancient Greek texts often used scriptio continua ('continuous writing'), which means that ancient authors and scribes would write word after word with no spaces or punctuation between words to differentiate or mark boundaries. Boustrophedon , or bi-directional text,

2436-630: Is the Greek alphabet , which has been used for approximately 2,800 years; previously, Greek was recorded in writing systems such as Linear B and the Cypriot syllabary . The alphabet arose from the Phoenician script and was in turn the basis of the Latin , Cyrillic , Coptic , Gothic , and many other writing systems. The Greek language holds a very important place in the history of the Western world. Beginning with

2523-491: Is to maintain a stable set of replica pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical Pods. The ReplicaSet can also be said to be a grouping mechanism that lets Kubernetes maintain the number of instances that have been declared for a given pod. The definition of a ReplicaSet uses a selector, whose evaluation will result in identifying all pods that are associated with it. A ReplicationController , similar to

2610-486: The Eastern Mediterranean , in what are today Southern Italy , Turkey , Cyprus , Syria , Lebanon , Israel , Palestine , Egypt , and Libya ; in the area of the Black Sea , in what are today Turkey, Bulgaria , Romania , Ukraine , Russia , Georgia , Armenia , and Azerbaijan ; and, to a lesser extent, in the Western Mediterranean in and around colonies such as Massalia , Monoikos , and Mainake . It

2697-510: The Indo-Iranian languages (see Graeco-Aryan ), but little definitive evidence has been found. In addition, Albanian has also been considered somewhat related to Greek and Armenian, and it has been proposed that they all form a higher-order subgroup along with other extinct languages of the ancient Balkans; this higher-order subgroup is usually termed Palaeo-Balkan , and Greek has a central position in it. Linear B , attested as early as

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2784-492: The nominal and verbal systems. The major change in the nominal morphology since the classical stage was the disuse of the dative case (its functions being largely taken over by the genitive ). The verbal system has lost the infinitive , the synthetically -formed future, and perfect tenses and the optative mood . Many have been replaced by periphrastic ( analytical ) forms. Pronouns show distinctions in person (1st, 2nd, and 3rd), number (singular, dual , and plural in

2871-418: The primary/replica architecture . The components of Kubernetes can be divided into those that manage an individual node and those that are part of the control plane. The Kubernetes master node handles the Kubernetes control plane of the cluster, managing its workload and directing communication across the system. The Kubernetes control plane consists of various components such as TLS encryption , RBAC , and

2958-540: The shim in favor of directly interfacing with the container through containerd, or replacing Docker with a runtime that is compliant with the Container Runtime Interface (CRI). With the release of v1.24 in May 2022, the "dockershim" has been removed entirely. Examples of popular container runtimes that are compatible with kubelet include containerd (initially supported via Docker), rkt and CRI-O . kube-proxy

3045-465: The 3rd millennium BC, or possibly earlier. The earliest written evidence is a Linear B clay tablet found in Messenia that dates to between 1450 and 1350 BC, making Greek the world's oldest recorded living language . Among the Indo-European languages, its date of earliest written attestation is matched only by the now-extinct Anatolian languages . The Greek language is conventionally divided into

3132-501: The Deployment controller finds that only two instances are running (conflicting with the etcd declaration), it schedules the creation of an additional instance of that pod. The scheduler is an extensible component that selects the node that an unscheduled pod (the basic unit of workloads to be scheduled) runs, based on resource availability and other constraints. The scheduler tracks resource allocation on each node to ensure that workload

3219-486: The Greek alphabet since approximately the 9th century BC. It was created by modifying the Phoenician alphabet , with the innovation of adopting certain letters to represent the vowels. The variant of the alphabet in use today is essentially the late Ionic variant, introduced for writing classical Attic in 403 BC. In classical Greek, as in classical Latin, only upper-case letters existed. The lower-case Greek letters were developed much later by medieval scribes to permit

3306-425: The Greek language are often emphasized. Although Greek has undergone morphological and phonological changes comparable to those seen in other languages, never since classical antiquity has its cultural, literary, and orthographic tradition been interrupted to the extent that one can speak of a new language emerging. Greek speakers today still tend to regard literary works of ancient Greek as part of their own rather than

3393-491: The Greek language was the Cypriot syllabary (also a descendant of Linear A via the intermediate Cypro-Minoan syllabary ), which is closely related to Linear B but uses somewhat different syllabic conventions to represent phoneme sequences. The Cypriot syllabary is attested in Cyprus from the 11th century BC until its gradual abandonment in the late Classical period, in favor of the standard Greek alphabet. Greek has been written in

3480-629: The Greek verb have likewise remained largely the same over the course of the language's history but with significant changes in the number of distinctions within each category and their morphological expression. Greek verbs have synthetic inflectional forms for: Many aspects of the syntax of Greek have remained constant: verbs agree with their subject only, the use of the surviving cases is largely intact (nominative for subjects and predicates, accusative for objects of most verbs and many prepositions, genitive for possessors), articles precede nouns, adpositions are largely prepositional, relative clauses follow

3567-661: The Greek-Albanian border. A significant percentage of Albania's population has knowledge of the Greek language due in part to the Albanian wave of immigration to Greece in the 1980s and '90s and the Greek community in the country. Prior to the Greco-Turkish War and the resulting population exchange in 1923 a very large population of Greek-speakers also existed in Turkey , though very few remain today. A small Greek-speaking community

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3654-468: The ReplicaSet controller manages the scale of the ReplicaSet, the Deployment controller manages what happens to the ReplicaSet – whether an update has to be rolled out, or rolled back, etc. When Deployments are scaled up or down, this results in the declaration of the ReplicaSet changing, and this change in the declared state is managed by the ReplicaSet controller. StatefulSets are controllers that enforce

3741-499: The actual cluster state toward the desired state, communicating with the API server to create, update, and delete the resources it manages (e.g., pods or service endpoints). An example controller is a ReplicaSet controller, which handles replication and scaling by running a specified number of copies of a pod across the cluster. The controller also handles creating replacement pods if the underlying node fails. Other controllers that are part of

3828-404: The acute during the late 20th century, and it has only been retained in typography . After the writing reform of 1982, most diacritics are no longer used. Since then, Greek has been written mostly in the simplified monotonic orthography (or monotonic system), which employs only the acute accent and the diaeresis. The traditional system, now called the polytonic orthography (or polytonic system),

3915-418: The album Telephono Other uses in arts, entertainment, and media [ edit ] Primaries or primary beams, in E. E. Smith's science-fiction series Lensman Primary (film) , American political documentary (1960) Computing [ edit ] PRIMARY, an X Window selection Primary data storage , computer technology used to retain digital data Primary server , main server on

4002-402: The ancient language; singular and plural alone in later stages), and gender (masculine, feminine, and neuter), and decline for case (from six cases in the earliest forms attested to four in the modern language). Nouns, articles, and adjectives show all the distinctions except for a person. Both attributive and predicative adjectives agree with the noun. The inflectional categories of

4089-456: The application to which these objects have been bound via the Deployment. A Secret and/or a ConfigMap is sent to a node only if a pod on that node requires it, which will only be stored in memory on the node. Once the pod that depends on the Secret or ConfigMap is deleted, the in-memory copy of all bound Secrets and ConfigMaps are deleted as well. The data from a ConfigMap or Secret is accessible to

4176-527: The cluster, representing the overall state of the cluster at any given point of time. etcd favors consistency over availability in the event of a network partition (see CAP theorem ). The consistency is crucial for correctly scheduling and operating services. The API server serves the Kubernetes API using JSON over HTTP , which provides both the internal and external interface to Kubernetes. The API server processes, validates REST requests, and updates

4263-429: The cluster. Generally, most workloads scale in response to a desired replica count, depending on the availability and performance requirements as needed by the application. However, in other scenarios it may be necessary to deploy a pod to every single node in the cluster, scaling up the number of total pods as nodes are added and garbage collecting them as they are removed. This is particularly helpful for use cases where

4350-406: The control plane. kubelet monitors the state of a pod, and if not in the desired state, the pod re-deploys to the same node. Node status is relayed every few seconds via heartbeat messages to the API server. Once the control plane detects a node failure, a higher-level controller is expected to observe this state change and launch pods on another healthy node. A container runtime is responsible for

4437-451: The core Kubernetes system include a DaemonSet controller for running exactly one pod on every machine (or some subset of machines), and a Job controller for running pods that run to completion (e.g. as part of a batch job). Labels selectors often form part of the controller's definition that specify the set of pods that a controller manages. The controller manager is a single process that manages several core Kubernetes controllers (including

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4524-404: The early 19th century that was used for literary and official purposes in the newly formed Greek state. In 1976, Dimotiki was declared the official language of Greece, after having incorporated features of Katharevousa and thus giving birth to Standard Modern Greek , used today for all official purposes and in education . The historical unity and continuing identity between the various stages of

4611-602: The epics of Homer , ancient Greek literature includes many works of lasting importance in the European canon . Greek is also the language in which many of the foundational texts in science and philosophy were originally composed. The New Testament of the Christian Bible was also originally written in Greek. Together with the Latin texts and traditions of the Roman world , the Greek texts and Greek societies of antiquity constitute

4698-408: The examples described above), is distributed as part of the standard Kubernetes installation and responding to the loss of nodes. Custom controllers may also be installed in the cluster, further allowing the behavior and API of Kubernetes to be extended when used in conjunction with custom resources (see custom resources, controllers and operators below). A node, also known as a worker or a minion,

4785-452: The following periods: In the modern era, the Greek language entered a state of diglossia : the coexistence of vernacular and archaizing written forms of the language. What came to be known as the Greek language question was a polarization between two competing varieties of Modern Greek: Dimotiki , the vernacular form of Modern Greek proper, and Katharevousa , meaning 'purified', a compromise between Dimotiki and Ancient Greek developed in

4872-709: The 💕 For Misplaced Pages's policy on primary sources , see Misplaced Pages:No original research § Primary . [REDACTED] Look up primary in Wiktionary, the free dictionary. Primary or primaries may refer to: Arts, entertainment, and media [ edit ] Music [ edit ] Groups and labels [ edit ] Primary (band) , from Australia Primary (musician) , hip hop musician and record producer from South Korea Primary Music , Israeli record label Works [ edit ] Primary (album) by Rubicon (2002) "Primary" (song) by The Cure "Primary", song by Spoon from

4959-439: The infinitive entirely (employing a raft of new periphrastic constructions instead) and uses participles more restrictively. The loss of the dative led to a rise of prepositional indirect objects (and the use of the genitive to directly mark these as well). Ancient Greek tended to be verb-final, but neutral word order in the modern language is VSO or SVO. Modern Greek inherits most of its vocabulary from Ancient Greek, which in turn

5046-463: The late 15th century BC, was the first script used to write Greek. It is basically a syllabary , which was finally deciphered by Michael Ventris and John Chadwick in the 1950s (its precursor, Linear A , has not been deciphered and most likely encodes a non-Greek language). The language of the Linear B texts, Mycenaean Greek , is the earliest known form of Greek. Another similar system used to write

5133-478: The lifecycle of containers, including launching, reconciling and killing of containers. kubelet interacts with container runtimes via the Container Runtime Interface (CRI), which decouples the maintenance of core Kubernetes from the actual CRI implementation. Originally, kubelet interfaced exclusively with the Docker runtime through a "dockershim". However, from November 2020 up to April 2022, Kubernetes has deprecated

5220-419: The lifetime of the pod itself. This storage can also be used as shared disk space for containers within the pod. Volumes are mounted at specific mount points within the container, which are defined by the pod configuration, and cannot mount onto other volumes or link to other volumes. The same volume can be mounted at different points in the file system tree by different containers. A common application challenge

5307-412: The major public cloud vendors. Kubernetes is one of the most widely deployed software systems in the world being used across companies including Google , Microsoft , Amazon , Apple , Meta , Nvidia , Reddit and Pinterest . Kubernetes ( Ancient Greek : κυβερνήτης , romanized :  kubernḗtēs , ' steersman, navigator ' or ' guide ' , and the etymological root of cybernetics )

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5394-621: The membership of Greece and Cyprus in the European Union, Greek is one of the organization's 24 official languages . Greek is recognized as a minority language in Albania, and used co-officially in some of its municipalities, in the districts of Gjirokastër and Sarandë . It is also an official minority language in the regions of Apulia and Calabria in Italy. In the framework of the European Charter for Regional or Minority Languages , Greek

5481-441: The modern period. The division into conventional periods is, as with all such periodizations, relatively arbitrary, especially because, in all periods, Ancient Greek has enjoyed high prestige, and the literate borrowed heavily from it. Across its history, the syllabic structure of Greek has varied little: Greek shows a mixed syllable structure, permitting complex syllabic onsets but very restricted codas. It has only oral vowels and

5568-546: The more important are: Containers emerged as a way to make software portable. The container contains all the packages needed to run a service. The provided file system makes containers extremely portable and easy to use in development. A container can be moved from development to test or production with no or relatively few configuration changes. Greek language Greek ( Modern Greek : Ελληνικά , romanized :  Elliniká , [eliniˈka] ; Ancient Greek : Ἑλληνική , romanized :  Hellēnikḗ )

5655-401: The notion of a primary instance and secondary instances. In this case, the notion of ordering of instances is important. Other applications like Apache Kafka distribute the data amongst their brokers; hence, one broker is not the same as another. In this case, the notion of instance uniqueness is important. DaemonSets are responsible for ensuring that a pod is created on every single node in

5742-399: The noun they modify and relative pronouns are clause-initial. However, the morphological changes also have their counterparts in the syntax, and there are also significant differences between the syntax of the ancient and that of the modern form of the language . Ancient Greek made great use of participial constructions and of constructions involving the infinitive, and the modern variety lacks

5829-521: The objects of study of the discipline of Classics . During antiquity , Greek was by far the most widely spoken lingua franca in the Mediterranean world . It eventually became the official language of the Byzantine Empire and developed into Medieval Greek . In its modern form , Greek is the official language of Greece and Cyprus and one of the 24 official languages of the European Union . It

5916-706: The older periods of Greek, loanwords into Greek acquired Greek inflections, thus leaving only a foreign root word. Modern borrowings (from the 20th century on), especially from French and English, are typically not inflected; other modern borrowings are derived from Albanian , South Slavic ( Macedonian / Bulgarian ) and Eastern Romance languages ( Aromanian and Megleno-Romanian ). Greek words have been widely borrowed into other languages, including English. Example words include: mathematics , physics , astronomy , democracy , philosophy , athletics , theatre, rhetoric , baptism , evangelist , etc. Moreover, Greek words and word elements continue to be productive as

6003-487: The oldest period in the Geologic time scale (obsolete) Primary, a stage in a thermonuclear explosive Primary circuit , electrical circuit in a transformer that receives current, as opposed to secondary circuit Primary field , type of field in conformal field theory Primary mirror , principal light-gathering surface of a reflecting telescope Primary power line , electric power transmission line fed to or from

6090-600: The pod through one of the following ways: The biggest difference between a Secret and a ConfigMap is that Secrets are specifically designed for containing secure and confidential data, although they are not encrypted at rest by default, and requires additional setup in order to fully secure the use of Secrets within the cluster. Secrets are often used to store confidential or sensitive data like certificates, credentials to work with image registries, passwords, and ssh keys. Kubernetes enables clients (users or internal components) to attach keys called labels to any API object in

6177-574: The principal competitors rallied around Kubernetes and announced adding native support for it: On March 6, 2018, Kubernetes Project reached ninth place in the list of GitHub projects by the number of commits , and second place in authors and issues, after the Linux kernel . Until version 1.18, Kubernetes followed an N-2 support policy, meaning that the three most recent minor versions receive security updates and bug fixes. Starting with version 1.19, Kubernetes follows an N-3 support policy. Kubernetes defines

6264-499: The properties of uniqueness and ordering amongst instances of a pod, and can be used to run stateful applications. While scaling stateless applications is only a matter of adding more running pods, doing so for stateful workloads is harder, because the state needs to be preserved if a pod is restarted. If the application is scaled up or down, the state may need to be redistributed. Databases are an example of stateful workloads. When run in high-availability mode, many databases come with

6351-434: The running application, libraries, and their dependencies. Kubernetes supports several abstractions of workloads that are at a higher level over simple pods. This allows users to declaratively define and manage these high-level abstractions, instead of having to manage individual pods by themselves. Several of these abstractions, supported by a standard installation of Kubernetes, are described below. A ReplicaSet 's purpose

6438-524: The selection is based on the attribute values inherent to the resource being selected, rather than user-defined categorization. metadata.name and metadata.namespace are field selectors that will be present on all Kubernetes objects. Other selectors that can be used depend on the object/resource type. Add-ons are additional features of the Kubernetes cluster implemented as applications running within it. The pods may be managed by Deployments, ReplicationControllers, and so on. There are many add-ons. Some of

6525-459: The server farm Education [ edit ] Primary education , the first stage of compulsory education Primary FRCA , academic examination for anaesthetists in the U.K. Primary school , school providing primary education Mathematics [ edit ] p -group of prime power order Primary decomposition into primary ideals Primary ideals , concept in commutative algebra Primary number , positive integer power of

6612-477: The state of the API objects in etcd, thereby allowing clients to configure workloads and containers across worker nodes. The API server uses etcd's watch API to monitor the cluster, roll out critical configuration changes, or restore any divergences of the state of the cluster back to the desired state as declared in etcd. As an example, a human operator may specify that three instances of a particular "pod" (see below) need to be running, and etcd stores this fact. If

6699-437: The stressed vowel; the so-called breathing marks ( rough and smooth breathing ), originally used to signal presence or absence of word-initial /h/; and the diaeresis , used to mark the full syllabic value of a vowel that would otherwise be read as part of a diphthong. These marks were introduced during the course of the Hellenistic period. Actual usage of the grave in handwriting saw a rapid decline in favor of uniform usage of

6786-665: The system, such as pods and nodes . Correspondingly, label selectors are queries against labels that resolve to matching objects. When a service is defined, one can define the label selectors that will be used by the service router/load balancer to select the pod instances that the traffic will be routed to. Thus, simply changing the labels of the pods or changing the label selectors on the service can be used to control which pods get traffic and which don't, which can be used to support various deployment patterns like blue–green deployments or A/B testing . This capability to dynamically control how services utilize implementing resources provides

6873-453: The workload has some dependency on the actual node or host machine, such as log collection, ingress controllers, and storage services. A Kubernetes service is a set of pods that work together, such as one tier of a multi-tier application. The set of pods that constitute a service are defined by a label selector. Kubernetes provides two modes of service discovery , using environment variables or using Kubernetes DNS. Service discovery assigns

6960-568: Was a distinct dialect of Greek itself. Aside from the Macedonian question, current consensus regards Phrygian as the closest relative of Greek, since they share a number of phonological, morphological and lexical isoglosses , with some being exclusive between them. Scholars have proposed a Graeco-Phrygian subgroup out of which Greek and Phrygian originated. Among living languages, some Indo-Europeanists suggest that Greek may be most closely related to Armenian (see Graeco-Armenian ) or

7047-549: Was also used as the official language of government and religion in the Christian Nubian kingdoms , for most of their history. Greek, in its modern form, is the official language of Greece, where it is spoken by almost the entire population. It is also the official language of Cyprus (nominally alongside Turkish ) and the British Overseas Territory of Akrotiri and Dhekelia (alongside English ). Because of

7134-546: Was also used in Ancient Greek. Greek has occasionally been written in the Latin script , especially in areas under Venetian rule or by Greek Catholics . The term Frankolevantinika / Φραγκολεβαντίνικα applies when the Latin script is used to write Greek in the cultural ambit of Catholicism (because Frankos / Φράγκος is an older Greek term for West-European dating to when most of (Roman Catholic Christian) West Europe

7221-469: Was announced by Google on June 6, 2014. The project was conceived and created by Google employees Joe Beda, Brendan Burns, and Craig McLuckie. Others at Google soon joined to help build the project including Ville Aikas, Dawn Chen, Brian Grant, Tim Hockin, and Daniel Smith. Other companies such as Red Hat and CoreOS joined the effort soon after, with notable contributors such as Clayton Coleman and Kelsey Hightower . The design and development of Kubernetes

7308-593: Was announced in June, 2014 and version 1.0 was released on July 21, 2015. Google worked with the Linux Foundation to form the Cloud Native Computing Foundation (CNCF) and offered Kubernetes as the seed technology. Google was already offering a managed Kubernetes service, GKE , and Red Hat was supporting Kubernetes as part of OpenShift since the inception of the Kubernetes project in 2014. In 2017,

7395-544: Was inspired by Google's Borg cluster manager and based on Promise Theory . Many of its top contributors had previously worked on Borg; they codenamed Kubernetes " Project 7 " after the Star Trek ex- Borg character Seven of Nine and gave its logo a seven-spoked ship's wheel (designed by Tim Hockin). Unlike Borg, which was written in C++ , Kubernetes is written in the Go language. Kubernetes

7482-566: Was under the control of the Frankish Empire ). Frankochiotika / Φραγκοχιώτικα (meaning 'Catholic Chiot') alludes to the significant presence of Catholic missionaries based on the island of Chios . Additionally, the term Greeklish is often used when the Greek language is written in a Latin script in online communications. The Latin script is nowadays used by the Greek-speaking communities of Southern Italy . The Yevanic dialect

7569-653: Was written by Romaniote and Constantinopolitan Karaite Jews using the Hebrew Alphabet . In a tradition, that in modern time, has come to be known as Greek Aljamiado , some Greek Muslims from Crete wrote their Cretan Greek in the Arabic alphabet . The same happened among Epirote Muslims in Ioannina . This also happened among Arabic-speaking Byzantine rite Christians in the Levant ( Lebanon , Palestine, and Syria ). This usage

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