Ndikukupemphani kuti muwerenge zolemba za "Hadoop. ZooKeeper" kuchokera ku mndandanda wakuti "Njira zogawira kugawidwa kwa deta yambiri ku Hadoop"
Kodi ZooKeeper ndi chiyani, malo ake mu Hadoop ecosystem. Zonama pamakompyuta ogawidwa. Chithunzi cha dongosolo logawidwa lokhazikika. Kuvuta kugwirizanitsa machitidwe ogawidwa. Zovuta zofananira zolumikizana. Mfundo zomwe zidapangidwa ndi ZooKeeper. ZooKeeper data model. mbendera za znode. Magawo. Client API. Zoyamba (masinthidwe, umembala wamagulu, maloko osavuta, zisankho za atsogoleri, kutseka popanda zotsatira zamagulu). ZooKeeper zomangamanga. ZooKeeper DB. ZAB. Pemphani woyang'anira.
Lero tikambirana za ZooKeeper. Chinthu ichi ndi chothandiza kwambiri. Iwo, monga mankhwala aliwonse a Apache Hadoop, ali ndi logo. Chimaimira munthu.
Izi zisanachitike, tidakambirana makamaka za momwe deta ingasinthidwe pamenepo, momwe mungasungire, ndiko kuti, momwe mungagwiritsire ntchito mwanjira ina ndikugwirira ntchito mwanjira ina. Ndipo lero ndikufuna kulankhula pang'ono za kumanga mapulogalamu ogawidwa. Ndipo ZooKeeper ndi chimodzi mwazinthu zomwe zimakulolani kuti muchepetse nkhaniyi. Uwu ndi mtundu wautumiki womwe umapangidwira mtundu wina wa kugwirizanitsa kwa njira zomwe zimagawidwa m'machitidwe ogawidwa, m'magawo ogawidwa.
Kufunika kogwiritsa ntchito kotereku kukuchulukirachulukira tsiku ndi tsiku, ndizomwe maphunziro athu akukhudza. Kumbali imodzi, MapReduce ndi chimango chokonzekerachi chimakupatsani mwayi wowongolera zovutazi ndikumasula wopanga mapulogalamu kuti asalembe zoyambira monga kulumikizana ndi kugwirizanitsa njira. Koma kumbali ina, palibe amene amatsimikizira kuti izi sizidzayenera kuchitika. MapReduce kapena ma framework ena okonzeka nthawi zonse salowa m'malo ena omwe sangathe kukhazikitsidwa pogwiritsa ntchito izi. Kuphatikiza MapReduce yokha ndi gulu la ma projekiti ena a Apache; iwo, nawonso, amagawidwanso ntchito. Ndipo kuti kulemba kukhale kosavuta, adalemba ZooKeeper.
Monga mapulogalamu onse okhudzana ndi Hadoop, idapangidwa ndi Yahoo! Tsopano ndi ntchito yovomerezeka ya Apache. Sizinapangidwe mwachangu monga HBase. Ngati mupita ku JIRA HBase, ndiye kuti tsiku lililonse pali malipoti ambiri a cholakwika, malingaliro ambiri oti mukwaniritse china chake, mwachitsanzo, moyo mu polojekitiyo ukupitilirabe. Ndipo ZooKeeper, kumbali imodzi, ndi chinthu chosavuta, ndipo kumbali ina, izi zimatsimikizira kudalirika kwake. Ndipo ndiyosavuta kugwiritsa ntchito, ndichifukwa chake yakhala muyezo pamagwiritsidwe ntchito mkati mwa chilengedwe cha Hadoop. Choncho ndinaona kuti zingakhale zothandiza kuipendanso kuti ndimvetse momwe imagwirira ntchito komanso momwe mungagwiritsire ntchito.
Ichi ndi chithunzi chankhani yomwe tinali nayo. Titha kunena kuti ndi orthogonal ku chilichonse chomwe takambirana mpaka pano. Ndipo zonse zomwe zasonyezedwa apa, ku digiri imodzi kapena imzake, zimagwira ntchito ndi ZooKeeper, mwachitsanzo, ndi ntchito yomwe imagwiritsa ntchito zinthu zonsezi. Ngakhale HDFS kapena MapReduce samalemba ntchito zawo zofananira zomwe zingawathandize kwenikweni. Chifukwa chake, ZooKeeper imagwiritsidwa ntchito. Ndipo izi zimathandizira chitukuko ndi zinthu zina zokhudzana ndi zolakwika.
Kodi zonsezi zikuchokera kuti? Zikuwoneka kuti tidayambitsa mapulogalamu awiri ofanana pamakompyuta osiyanasiyana, kuwalumikiza ndi chingwe kapena mauna, ndipo chilichonse chimagwira ntchito. Koma vuto ndiloti Network ndi yosadalirika, ndipo ngati munawombera magalimoto kapena kuyang'ana zomwe zikuchitika kumeneko pamtunda wotsika, momwe makasitomala amachitira pa Network, nthawi zambiri mumatha kuona kuti mapaketi ena atayika kapena atumizidwanso. Sizopanda pake kuti ma protocol a TCP adapangidwa, omwe amakulolani kukhazikitsa gawo lina ndikutsimikizira kutumiza mauthenga. Koma mulimonse, ngakhale TCP silingathe kukupulumutsani nthawi zonse. Chilichonse chili ndi nthawi yake. Netiweki imatha kugwa kwakanthawi. Ikhoza kungophethira. Ndipo izi zonse zimatsogolera ku mfundo yakuti simungathe kudalira Network kukhala yodalirika. Uku ndiye kusiyana kwakukulu pakulemba ntchito zofananira zomwe zimayenda pakompyuta imodzi kapena pakompyuta imodzi, pomwe palibe Network, pomwe pali basi yodalirika yosinthira deta kukumbukira. Ndipo uku ndiko kusiyana kwakukulu.
Mwa zina, mukamagwiritsa ntchito Network, nthawi zonse pamakhala latency. Diski imakhalanso nayo, koma Network ili ndi zambiri. Latency ndi nthawi yochedwa, yomwe ingakhale yaying'ono kapena yofunika kwambiri.
Network topology ikusintha. Kodi topology ndi chiyani - uku ndikuyika kwa zida zathu zapaintaneti. Pali malo opangira deta, pali ma racks omwe amaima pamenepo, pali makandulo. Zonsezi zikhoza kulumikizidwanso, kusuntha, ndi zina zotero. Izi zonse ziyeneranso kuganiziridwa. Mayina a IP amasintha, njira yomwe magalimoto athu amayendera amasintha. Izi ziyeneranso kuganiziridwa.
Maukonde amathanso kusintha malinga ndi zida. Kuchokera pakuchita, ndinganene kuti akatswiri athu apa intaneti amakonda kusinthira nthawi ndi nthawi china chake pamakandulo. Mwadzidzidzi firmware yatsopano idatuluka ndipo sanali chidwi kwenikweni ndi gulu lina la Hadoop. Ali ndi ntchito yawoyawo. Kwa iwo, chinthu chachikulu ndikuti Network imagwira ntchito. Chifukwa chake, akufuna kuyikanso china chake pamenepo, kuwunikira pazida zawo, ndipo zida zimasinthanso nthawi ndi nthawi. Zonsezi ziyenera kuganiziridwa mwanjira ina. Zonsezi zimakhudza ntchito yathu yogawidwa.
Kawirikawiri anthu omwe amayamba kugwira ntchito ndi deta yambiri pazifukwa zina amakhulupirira kuti intaneti ilibe malire. Ngati pali fayilo ya ma terabytes angapo pamenepo, mutha kupita nayo ku seva yanu kapena kompyuta ndikutsegula pogwiritsa ntchito mphaka ndi penyani. Cholakwika china chili mkati Vim yang'anani pa zipika. Osachita izi chifukwa ndi zoyipa. Chifukwa Vim amayesa kubisa chilichonse, sungani chilichonse kukumbukira, makamaka tikayamba kudutsa chipikachi ndikuyang'ana china chake. Izi ndi zinthu zomwe zayiwalika, koma zoyenera kuziganizira.
Ndikosavuta kulemba pulogalamu imodzi yomwe imayenda pakompyuta imodzi ndi purosesa imodzi.
Pamene dongosolo lathu likukula, timafuna kufanana nazo zonse, ndikuzifananitsa osati pa kompyuta, komanso pamagulu. Funso likubuka: momwe mungagwirizanitse nkhaniyi? Mapulogalamu athu mwina sangagwirizane, koma tidayendetsa njira zingapo mofananira pamaseva angapo. Ndipo mungayang'anire bwanji kuti zonse zikuwayendera bwino? Mwachitsanzo, amatumiza china chake pa intaneti. Ayenera kulemba za chikhalidwe chawo kwinakwake, mwachitsanzo, mumtundu wina wa database kapena chipika, ndikuphatikiza chipikachi ndikuchisanthula kwinakwake. Komanso, tiyenera kuganizira kuti ndondomekoyi ikugwira ntchito ndikugwira ntchito, mwadzidzidzi cholakwika china chinawonekera mmenemo kapena chinagwa, ndiye kuti tidzapeza bwanji za izo?
Zikuwonekeratu kuti zonsezi zitha kuyang'aniridwa mwachangu. Izi ndi zabwino, koma kuyang'anira ndi chinthu chochepa chomwe chimakupatsani inu kuyang'anira zinthu zina pamtunda wapamwamba.
Pamene tikufuna kuti njira zathu ziyambe kuyanjana wina ndi mzake, mwachitsanzo, kutumiza wina ndi mzake deta, ndiye kuti funso limakhalapo - izi zidzachitika bwanji? Kodi padzakhala mtundu wamtundu wamtundu, kodi adzalembana wina ndi mzake, kodi deta idzafika molondola, kodi chirichonse chidzatayika panjira? Tiyenera kupanga mtundu wina wa protocol, etc.
Kugwirizana kwa njira zonsezi si chinthu chaching'ono. Ndipo zimakakamiza wopanga mapulogalamuwo kuti atsike mpaka pamlingo wotsikirapo, ndikulemba machitidwe kuyambira koyambira, kapena osakhalanso, koma izi sizophweka.
Ngati mubwera ndi cryptographic algorithm kapena kuigwiritsa ntchito, ndiye kuti mutaya nthawi yomweyo, chifukwa mwina sichingagwire ntchito kwa inu. Idzakhala ndi zolakwika zambiri zomwe munayiwala kupereka. Osachigwiritsa ntchito pa chilichonse chovuta chifukwa chitha kukhala chosakhazikika. Chifukwa ma algorithms onse omwe alipo adayesedwa ndi nthawi kwa nthawi yayitali kwambiri. Zimasokonezedwa ndi anthu ammudzi. Uwu ndi mutu wosiyana. Ndipo ndi chimodzimodzi pano. Ngati ndi kotheka kuti musagwiritse ntchito mtundu wina wa kulunzanitsa nokha, ndiye kuti ndibwino kuti musachite izi, chifukwa ndizovuta kwambiri ndipo zimakufikitsani panjira yosasunthika yofufuza zolakwika nthawi zonse.
Lero tikukamba za ZooKeeper. Kumbali imodzi, ndi chimango, kumbali ina, ndi ntchito yomwe imapangitsa moyo kukhala wosavuta kwa wopanga mapulogalamuwo komanso kumathandizira kukhazikitsa malingaliro ndi kugwirizanitsa njira zathu momwe tingathere.
Tiyeni tikumbukire momwe dongosolo logawira lokhazikika lingawonekere. Izi ndi zomwe tidakambirana - HDFS, HBase. Pali njira ya Master yomwe imayang'anira antchito ndi machitidwe akapolo. Iye ali ndi udindo wogwirizanitsa ndi kugawa ntchito, kuyambitsanso antchito, kuyambitsa zatsopano, ndi kugawa katundu.
Chinthu chotsogola kwambiri ndi Coordination Service, ndiko kuti, kusuntha ntchito yolumikizira yokha m'njira ina, kuphatikiza kuyendetsa mtundu wina wa zosunga zobwezeretsera kapena Stanby Master mofananira, chifukwa Mbuyeyo akhoza kulephera. Ndipo ngati Mbuye agwa, ndiye kuti dongosolo lathu siligwira ntchito. Tikuyendetsa zosunga zobwezeretsera. Ena amati Master ayenera kusinthidwa kuti asungidwe. Izi zitha kuperekedwanso ku Coordination Service. Koma m'chithunzichi, Mbuye mwiniyo ali ndi udindo wogwirizanitsa antchito; apa ntchito ikugwirizanitsa ntchito zobwereza deta.
Njira yapamwamba kwambiri ndi pamene kugwirizana konse kumayendetsedwa ndi ntchito yathu, monga momwe zimakhalira nthawi zambiri. Amatenga udindo woonetsetsa kuti zonse zikuyenda bwino. Ndipo ngati china chake sichingagwire ntchito, timachipeza ndikuyesa kuzungulira izi. Mulimonse momwe zingakhalire, timasiyidwa ndi Mbuye yemwe mwanjira ina amalumikizana ndi akapolo ndipo amatha kutumiza deta, chidziwitso, mauthenga, ndi zina kudzera muutumiki wina.
Pali chiwembu chotsogola kwambiri, pamene tilibe Mbuye, ma node onse amakhala akapolo ambuye, osiyana m'makhalidwe awo. Koma amafunikabe kuyanjana wina ndi mzake, kotero patsalabe ntchito zina kuti zigwirizane ndi izi. Mwinamwake, Cassandra, yemwe amagwira ntchito pa mfundoyi, akugwirizana ndi ndondomekoyi.
Ndizovuta kunena kuti ndi iti mwa ziwembu zomwe zimagwira bwino ntchito. Iliyonse ili ndi zabwino ndi zoyipa zake.
Ndipo palibe chifukwa choopa zinthu zina ndi Mbuye, chifukwa, monga momwe zimasonyezera, samakhala wokonzeka kutumikira nthawi zonse. Chinthu chachikulu apa ndikusankha njira yoyenera yogwiritsira ntchito ntchitoyi pa node yamphamvu yosiyana, kotero kuti ikhale ndi zinthu zokwanira, kotero kuti ngati n'kotheka, ogwiritsa ntchito alibe mwayi pamenepo, kuti asaphe mwangozi ndondomekoyi. Koma panthawi imodzimodziyo, mu ndondomeko yotereyi ndi kosavuta kuyang'anira ogwira ntchito kuchokera ku ndondomeko ya Master, i.e. ndondomekoyi ndi yophweka kuchokera pakuwona kukhazikitsidwa.
Ndipo dongosolo ili (pamwambapa) mwina ndilovuta, koma lodalirika.
Vuto lalikulu ndi kulephera pang'ono. Mwachitsanzo, tikatumiza uthenga pa Network, ngozi yamtundu wina imachitika, ndipo amene watumiza uthengawo sangadziwe ngati uthenga wake walandilidwa komanso zomwe zidachitika kumbali ya wolandila, sangadziwe ngati uthengawo unakonzedwa bwino. , i.e. sadzalandira chitsimikiziro chilichonse.
Chifukwa chake, tiyenera kukonza izi. Ndipo chosavuta ndikutumizanso uthengawu ndikudikirira mpaka titalandira yankho. Pankhaniyi, sizikuganiziridwa ngati mkhalidwe wa wolandira wasintha. Titha kutumiza uthenga ndikuwonjezera zomwezo kawiri.
ZooKeeper imapereka njira zothetsera kukana koteroko, zomwe zimapangitsanso moyo wathu kukhala wosavuta.
Monga tanena kale, izi zikufanana ndi kulemba mapulogalamu amitundu yambiri, koma kusiyana kwakukulu ndikuti muzogawa zomwe timapanga pamakina osiyanasiyana, njira yokhayo yolumikizirana ndi Network. Kwenikweni, izi ndizomangamanga zogawana. Njira iliyonse kapena ntchito yomwe imagwira pamakina amodzi ili ndi kukumbukira kwake, disk yake, purosesa yake, yomwe sagawana ndi aliyense.
Ngati tilemba pulogalamu yamitundu yambiri pakompyuta imodzi, ndiye kuti titha kugwiritsa ntchito kukumbukira komwe timagawana kuti tisinthane deta. Tili ndi kusintha kosintha pamenepo, njira zimatha kusintha. Izi zimakhudza magwiridwe antchito. Kumbali imodzi, palibe chinthu choterocho mu pulogalamu pamagulu, koma pali mavuto ndi Network.
Chifukwa chake, zovuta zazikulu zomwe zimachitika polemba machitidwe ogawidwa ndi kasinthidwe. Tikulemba mtundu wina wa ntchito. Ngati ndizosavuta, ndiye kuti timalemba manambala amitundu yonse mu code, koma izi ndizosasangalatsa, chifukwa ngati titha kusankha kuti m'malo mwa theka la sekondi tikufuna kutha kwa sekondi imodzi, ndiye kuti tiyenera kuyambiranso kugwiritsa ntchito ndikugwiritsa ntchito. tulutsani zonse kachiwiri. Ndi chinthu chimodzi pamene ili pamakina amodzi, mutha kungoyiyambitsanso, koma tikakhala ndi makina ambiri, tiyenera kukopera chilichonse nthawi zonse. Tiyenera kuyesa kuti pulogalamuyi ikhale yosinthika.
Apa tikukamba za static kasinthidwe kachitidwe kachitidwe. Izi siziri kwathunthu, mwinamwake kuchokera ku machitidwe ogwiritsira ntchito, zikhoza kukhala zosinthika zokhazikika pazochitika zathu, mwachitsanzo, izi ndizokonzekera zomwe sizingangotengedwa ndikusinthidwa.
Palinso kasinthidwe kosinthika. Awa ndi magawo omwe tikufuna kusintha pa ntchentche kuti anyamulidwe pamenepo.
Chavuta ndi chiyani apa? Tinasinthitsa config, kutulutsa, ndiye chiyani? Vuto likhoza kukhala kuti mbali imodzi tidatulutsa config, koma ndayiwala za chinthu chatsopano, config idakhalabe pamenepo. Kachiwiri, pamene tinali kutulutsa, kasinthidweko adasinthidwa m'malo ena, koma osati m'malo ena. Ndipo njira zina zamagwiritsidwe athu zomwe zimagwira pamakina amodzi zidayambikanso ndikusintha kwatsopano, ndipo kwinakwake ndi yakale. Izi zitha kupangitsa kuti pulogalamu yathu yogawidwa ikhale yosagwirizana ndi kawonedwe ka kasinthidwe. Vutoli ndi lofala. Kwa kasinthidwe kosinthika, ndikofunikira kwambiri chifukwa zikutanthauza kuti zitha kusinthidwa pouluka.
Vuto lina ndi umembala wamagulu. Nthawi zonse timakhala ndi antchito ena, nthawi zonse timafuna kudziwa kuti ndi ndani wa iwo amene ali wamoyo, yemwe wamwalira. Ngati pali Mbuye, ndiye kuti ayenera kumvetsetsa kuti ndi antchito ati omwe angatumizedwe kwa makasitomala kuti athe kuwerengera kapena kugwira ntchito ndi deta, ndi zomwe sizingatheke. Vuto lomwe limakhalapo nthawi zonse ndiloti tiyenera kudziwa yemwe akugwira ntchito mumagulu athu.
Vuto linanso ndi zisankho za atsogoleri, tikafuna kudziwa amene akutsogolera. Chitsanzo chimodzi ndi kubwerezabwereza, tikakhala ndi ndondomeko yomwe imalandira ntchito zolembera ndikuzibwereza mwa njira zina. Iye adzakhala mtsogoleri, aliyense adzamvera iye, adzamutsatira iye. Ndikofunika kusankha ndondomeko kuti ikhale yosamvetsetseka kwa aliyense, kuti asatuluke kuti atsogoleri awiri asankhidwa.
Palinso mwayi wogwirizana. Vuto pano ndi lovuta kwambiri. Pali chinthu chonga mutex, pamene mulemba mapulogalamu amitundu yambiri ndipo mukufuna kupeza zinthu zina, mwachitsanzo, selo la kukumbukira, kuti likhale lochepa ndi kuchitidwa ndi ulusi umodzi wokha. Apa gwero likhoza kukhala linanso losamvetsetseka. Ndipo mapulogalamu osiyanasiyana ochokera kumagulu osiyanasiyana a Network yathu ayenera kulandira mwayi wopezeka kuzinthu zomwe zapatsidwa, osati kuti aliyense asinthe kapena kulemba chinachake pamenepo. Awa ndi omwe amatchedwa maloko.
ZooKeeper imakupatsani mwayi wothana ndi mavuto onsewa pamlingo umodzi kapena wina. Ndipo ndikuwonetsa ndi zitsanzo momwe zimakulolani kuchita izi.
Palibe zoletsa zoyambira. Tikayamba kugwiritsa ntchito china chake, choyambirira sichingadikire kuti chochitika chilichonse chichitike. Mwinamwake, chinthu ichi chidzagwira ntchito mofanana, motero kulola kuti njira zisapachike pamene akuyembekezera chinachake. Ichi ndi chinthu chothandiza kwambiri.
Zopempha zonse zamakasitomala zimakonzedwa motsatira mzere wamba.
Ndipo makasitomala ali ndi mwayi wolandira zidziwitso za kusintha kwa dziko lina, za kusintha kwa deta, kasitomala asanayambe kuona zomwe zasinthidwa okha.
ZooKeeper imatha kugwira ntchito m'njira ziwiri. Yoyamba ndi yodziyimira payokha, pa mfundo imodzi. Izi ndizosavuta kuyesa. Itha kugwiranso ntchito mumagulu amagulu pamagulu aliwonse a seva. Ngati tili ndi gulu la makina 100, ndiye kuti sikofunikira kuti igwire ntchito pamakina 100. Ndikokwanira kusankha makina angapo komwe mungayendetse ZooKeeper. Ndipo amadzinenera mfundo ya kupezeka mkulu. Pazochitika zilizonse, ZooKeeper imasunga deta yonse. Kenako ndikuuzani momwe amachitira. Simagawanitsa deta kapena kuigawa. Kumbali imodzi, ndizochepa zomwe sitingathe kusunga zambiri, kumbali ina, palibe chifukwa chochitira izi. Izi sizomwe zidapangidwira, si database.
Deta ikhoza kusungidwa kumbali ya kasitomala. Iyi ndi mfundo yokhazikika kuti tisasokoneze ntchitoyo komanso kuti tisayike ndi zopempha zomwezo. Kasitomala wanzeru nthawi zambiri amadziwa izi ndikusunga.
Mwachitsanzo, zinthu zasintha apa. Pali mtundu wina wa ntchito. Mtsogoleri watsopano adasankhidwa, yemwe ali ndi udindo, mwachitsanzo, pokonza ntchito zolembera. Ndipo tikufuna kubwereza deta. Njira imodzi ndiyo kuyiyika mu lupu. Ndipo timakayikira nthawi zonse ntchito yathu - pali chilichonse chasintha? Njira yachiwiri ndi yabwino kwambiri. Iyi ndi njira yowonera yomwe imakupatsani mwayi wodziwitsa makasitomala kuti china chake chasintha. Iyi ndi njira yotsika mtengo pankhani yazachuma komanso yabwino kwa makasitomala.
Makasitomala ndi wogwiritsa ntchito ZooKeeper.
Seva ndiye njira ya ZooKeeper yokha.
Znode ndiye chinthu chofunikira kwambiri mu ZooKeeper. Ma znode onse amasungidwa pamtima ndi ZooKeeper ndipo amapangidwa mwa mawonekedwe azithunzi zotsogola, monga mtengo.
Pali mitundu iwiri ya ntchito. Choyamba ndikusintha / kulemba, pamene ntchito ina ikusintha mkhalidwe wa mtengo wathu. Mtengowo ndi wamba.
Ndipo ndizotheka kuti kasitomala samaliza pempho limodzi ndipo amachotsedwa, koma akhoza kukhazikitsa gawo lomwe limalumikizana ndi ZooKeeper.
ZooKeeper's data model ikufanana ndi fayilo. Pali muzu wokhazikika ndiyeno tidapita ngati kudzera muzolemba zomwe zimachokera muzu. Ndiyeno kabukhu la mlingo woyamba, mlingo wachiwiri. Izi zonse ndi znodes.
Znode iliyonse imatha kusunga deta, nthawi zambiri osati yayikulu kwambiri, mwachitsanzo, 10 kilobytes. Ndipo znode iliyonse imatha kukhala ndi ana angapo.
Znodes amabwera m'mitundu ingapo. Iwo akhoza kulengedwa. Ndipo popanga znode, timatchula mtundu womwe uyenera kukhala nawo.
Pali mitundu iwiri. Choyamba ndi mbendera ya ephemeral. Znode amakhala mkati mwa gawo. Mwachitsanzo, kasitomala wakhazikitsa gawo. Ndipo malinga ngati gawoli liri lamoyo, lidzakhalapo. Izi ndizofunikira kuti musapange chinthu chosafunika. Izi ndizoyeneranso nthawi yomwe kuli kofunikira kuti tisunge zoyambira mkati mwa gawo.
Mtundu wachiwiri ndi mbendera yotsatizana. Imawonjezera kauntala panjira yopita ku znode. Mwachitsanzo, tinali ndi chikwatu chokhala ndi ntchito 1_5. Ndipo titapanga node yoyamba, idalandira p_1, yachiwiri - p_2. Ndipo tikamatchula njirayi nthawi iliyonse, timadutsa njira yonse, kusonyeza gawo limodzi la njirayo, ndipo chiwerengerochi chimangowonjezereka chifukwa timasonyeza mtundu wa node - sequential.
Nthawi zonse znode. Adzakhala ndi moyo nthawi zonse ndipo ali ndi dzina limene timamuuza.
Chinthu chinanso chothandiza ndi mbendera ya wotchi. Ngati tiyiyika, ndiye kuti kasitomala akhoza kulembetsa ku zochitika zina pa node inayake. Ndikuwonetsani pambuyo pake ndi chitsanzo momwe izi zimachitikira. ZooKeeper yokha imadziwitsa kasitomala kuti zomwe zili pa node zasintha. Komabe, zidziwitso sizikutsimikizira kuti zatsopano zafika. Amangonena kuti china chake chasintha, ndiye kuti muyenera kufananizabe pambuyo pake ndi mafoni osiyana.
Ndipo monga ndanenera kale, dongosolo la deta limatsimikiziridwa ndi ma kilobytes. Palibe chifukwa chosungira zolemba zazikulu pamenepo, chifukwa si database, ndi seva yogwirizanitsa zochita.
Ndikuuzani pang'ono za magawo. Ngati tili ndi ma seva angapo, ndiye kuti titha kusuntha mowonekera kuchokera ku seva kupita ku seva pogwiritsa ntchito chizindikiritso cha gawo. Ndi yabwino ndithu.
Gawo lililonse limakhala ndi nthawi yomaliza. Gawo limatanthauzidwa ngati kasitomala amatumiza chilichonse ku seva panthawiyo. Ngati sanapatsire chilichonse panthawi yomwe yatha, gawolo limagwa, kapena kasitomala atha kutseka yekha.
Ilibe zinthu zambiri, koma mutha kuchita zinthu zosiyanasiyana ndi API iyi. Kuitana kumeneko tidawona kumapanga znode ndipo kumatenga magawo atatu. Iyi ndi njira yopita ku znode, ndipo iyenera kufotokozedwa kwathunthu kuchokera muzu. Komanso izi ndi zina deta kuti tikufuna kusamutsa kumeneko. Ndi mtundu wa mbendera. Ndipo pambuyo pa chilengedwe chimabwezeretsa njira yopita ku znode.
Chachiwiri, mukhoza kuchotsa. Chinyengo apa ndikuti gawo lachiwiri, kuwonjezera pa njira yopita ku znode, limatha kufotokozera mtunduwo. Chifukwa chake, znodeyo idzachotsedwa ngati mtundu wake womwe tidasamutsa uli wofanana ndi womwe ulipo.
Ngati sitikufuna kuyang'ana bukuli, ndiye kuti timangopereka mkangano wa "-1".
Chachitatu, imayang'ana ngati znode ilipo. Imabwezeranso zoona ngati mfundo ilipo, zabodza mwanjira ina.
Kenako wotchi ya mbendera imawonekera, yomwe imakulolani kuti muwunikire node iyi.
Mutha kuyika mbenderayi ngakhale pa mfundo yomwe palibe ndi kulandira zidziwitso zikawoneka. Izi zingakhalenso zothandiza.
Pali zovuta zina zingapo getData. Zikuwonekeratu kuti tikhoza kulandira deta kudzera pa znode. Mukhozanso kugwiritsa ntchito mbendera. Pankhaniyi, sichidzayika ngati palibe mfundo. Choncho, muyenera kumvetsa kuti alipo, ndiyeno kulandira deta.
Palinso SetData. Apa tikudutsa Baibulo. Ndipo ngati tipereka izi, zomwe zili paznode ya mtundu wina zidzasinthidwa.
Mutha kutchulanso "-1" kuti musaphatikizepo cheke ichi.
Njira ina yothandiza ndi kupezaAna. Tithanso kupeza mndandanda wa ma znode onse omwe ali ake. Titha kuyang'anira izi pokhazikitsa wotchi ya mbendera.
Ndipo njira Sync amalola zosintha zonse kutumizidwa nthawi imodzi, potero kuonetsetsa kuti zasungidwa ndipo deta yonse yasinthidwa kwathunthu.
Ngati tijambula mafananidwe ndi mapulogalamu okhazikika, ndiye mukamagwiritsa ntchito njira monga kulemba, zomwe zimalembera chinachake ku disk, ndipo pambuyo pobwezera yankho kwa inu, palibe chitsimikizo kuti mwalemba deta ku disk. Ndipo ngakhale makina ogwiritsira ntchito ali otsimikiza kuti zonse zalembedwa, pali njira mu diski yokha momwe ndondomekoyi imadutsa mumagulu a buffers, ndipo pambuyo pake deta imayikidwa pa disk.
Nthawi zambiri mafoni asynchronous amagwiritsidwa ntchito. Izi zimathandiza kuti kasitomala azigwira ntchito limodzi ndi zopempha zosiyanasiyana. Mutha kugwiritsa ntchito njira yolumikizirana, koma ndiyopanda phindu.
Ntchito ziwiri zomwe takambirana ndikusintha / kulemba, zomwe zimasintha deta. Izi ndikupanga, setData, kulunzanitsa, kufufuta. Ndipo kuwerenga kulipo, getData, getChildren.
Tsopano zitsanzo zingapo za momwe mungapangire zoyambira zogwirira ntchito mudongosolo logawidwa. Mwachitsanzo, zokhudzana ndi kasinthidwe ka chinthu. Wantchito watsopano wawonekera. Tinawonjezera makinawo ndikuyamba ntchito. Ndipo pali mafunso atatu otsatirawa. Kodi imafunsa bwanji ZooKeeper kuti isinthidwe? Ndipo ngati tikufuna kusintha kasinthidwe, timasintha bwanji? Ndipo titasintha, kodi ogwira ntchito omwe tinali nawo amapeza bwanji?
ZooKeeper imapangitsa izi kukhala zosavuta. Mwachitsanzo, pali mtengo wathu wa znode. Pali node yogwiritsira ntchito pano, timapanga node yowonjezeramo, yomwe ili ndi deta kuchokera ku kasinthidwe. Izi zikhoza kukhala zosiyana kapena ayi. Popeza kukula kwake ndi kochepa, kukula kwa kasinthidwe kaŵirikaŵiri kumakhala kochepa kwambiri, kotero ndizotheka kusunga apa.
Mukugwiritsa ntchito njira getData kuti mupeze kasinthidwe kwa wogwira ntchito kuchokera ku node. Khazikitsani ku zoona. Ngati pazifukwa zina node iyi kulibe, tidzadziwitsidwa za iyo ikawoneka, kapena ikasintha. Ngati tikufuna kudziwa kuti china chake chasintha, timachiyika kukhala chowona. Ndipo ngati zomwe zili mu node iyi zisintha, tidzadziwa.
SetData. Timayika deta, timayika "-1", i.e. sitiyang'ana mtunduwo, timaganiza kuti nthawi zonse timakhala ndi kasinthidwe kamodzi, sitiyenera kusunga masinthidwe ambiri. Ngati mukufuna kusunga zambiri, muyenera kuwonjezera mlingo wina. Apa tikukhulupirira kuti pali imodzi yokha, kotero timangosintha yatsopano, kuti tisayang'ane mtunduwo. Pakadali pano, makasitomala onse omwe adalembetsa kale amalandira chidziwitso kuti china chake chasintha mu node iyi. Ndipo akalandira, ayeneranso kupempha deta kachiwiri. Chidziwitso ndikuti samalandira deta yokha, koma chidziwitso chokha cha kusintha. Pambuyo pake ayenera kupempha deta yatsopano.
Njira yachiwiri yogwiritsira ntchito akale ndi umembala wagulu. Tili ndi ntchito yogawidwa, pali gulu la antchito ndipo tikufuna kumvetsetsa kuti onse ali m'malo. Chifukwa chake, ayenera kudzilembera okha kuti akugwira ntchito muzofunsira zathu. Ndipo tikufunanso kudziwa, mwina kuchokera ku Master process kapena kwina kulikonse, za ogwira ntchito omwe tili nawo pano.
Kodi timachita bwanji izi? Pogwiritsa ntchito, timapanga node ya ogwira ntchito ndikuwonjezera sublevel pamenepo pogwiritsa ntchito njira yopangira. Ndili ndi vuto pa silaidi. Apa muyenera zotsatizana tchulani, ndiye antchito onse adzalengedwa mmodzimmodzi. Ndipo kugwiritsa ntchito, kupempha deta yonse ya ana a node iyi, imalandira antchito onse ogwira ntchito omwe alipo.
Uku ndikukhazikitsa koyipa kwa momwe izi zingachitikire mu Java code. Tiyeni tiyambe kuchokera kumapeto, ndi njira yayikulu. Ili ndi kalasi yathu, tiyeni tipange njira yake. Monga mkangano woyamba timagwiritsa ntchito host host, komwe tikulumikiza, mwachitsanzo, timayiyika ngati mkangano. Ndipo mkangano wachiwiri ndi dzina la gulu.
Kodi kugwirizana kumachitika bwanji? Ichi ndi chitsanzo chosavuta cha API chomwe chimagwiritsidwa ntchito. Chilichonse ndi chophweka pano. Pali kalasi yodziwika bwino ya ZooKeeper. Timadutsa makamu kwa izo. Ndipo ikani nthawi yothera, mwachitsanzo, mpaka masekondi 5. Ndipo tili ndi membala wotchedwa connectionSignal. Kwenikweni, timapanga gulu panjira yopatsirana. Sitilemba deta pamenepo, ngakhale kuti chinachake chikanalembedwa. Ndipo mfundo apa ndi ya mtundu wolimbikira. Kwenikweni, iyi ndi mfundo wamba wamba yomwe idzakhalapo nthawi zonse. Apa ndipamene gawoli limapangidwira. Uku ndiko kukhazikitsidwa kwa kasitomala wokha. Makasitomala athu amatumiza mauthenga nthawi ndi nthawi osonyeza kuti gawoli liri ndi moyo. Ndipo tikamaliza gawolo, timayitana pafupi ndipo ndizomwezo, gawolo limagwa. Izi ndichifukwa choti china chake chingatigwere, kuti ZooKeeper adziwe za izi ndikudula gawolo.
Kodi kutseka gwero? Apa chirichonse chiri chovuta pang'ono. Tili ndi gulu la ogwira ntchito, pali zida zina zomwe tikufuna kutseka. Kuti tichite izi, timapanga mfundo yosiyana, mwachitsanzo, yotchedwa lock1. Ngati tidatha kupanga, ndiye kuti tili ndi loko. Ndipo ngati sitinathe kulenga, ndiye wogwira ntchito amayesa kupeza GetData kuchokera pano, ndipo popeza node yapangidwa kale, ndiye timayika woyang'anira apa ndi nthawi yomwe mkhalidwe wa node ukusintha, tidzadziwa za izo. Ndipo titha kuyesa kukhala ndi nthawi yoti tipangenso. Ngati titenga mfundo iyi, titenga loko, ndiye kuti sitifunikanso loko, tidzasiya, popeza mfundoyi ilipo mkati mwa gawoli. Motero, zidzatha. Ndipo kasitomala wina, mkati mwa dongosolo la gawo lina, adzatha kutenga loko pa mfundoyi, kapena m'malo mwake, adzalandira chidziwitso kuti chinachake chasintha ndipo akhoza kuyesera kuchichita panthawi yake.
Chitsanzo china cha momwe mungasankhire mtsogoleri wamkulu. Izi ndizovuta kwambiri, komanso zosavuta. Kodi chikuchitika ndi chiyani pano? Pali node yayikulu yomwe imaphatikiza antchito onse. Tikuyesera kupeza zambiri za mtsogoleri. Ngati izi zidachitika bwino, mwachitsanzo, talandira deta, ndiye kuti wogwira ntchito wathu amayamba kutsatira mtsogoleriyu. Amakhulupirira kuti pali mtsogoleri.
Ngati mtsogoleri adamwalira pazifukwa zina, mwachitsanzo, adagwa, ndiye timayesetsa kupanga mtsogoleri watsopano. Ndipo ngati tipambana, ndiye kuti wantchito wathu amakhala mtsogoleri. Ndipo ngati wina panthawiyi adakwanitsa kupanga mtsogoleri watsopano, ndiye kuti timayesetsa kumvetsetsa kuti ndi ndani ndikumutsatira.
Apa zomwe zimatchedwa zotsatira za ng'ombe zimatuluka, mwachitsanzo, zotsatira za ng'ombe, chifukwa mtsogoleri akamwalira, yemwe ali woyamba mu nthawi adzakhala mtsogoleri.
Pogwira gwero, mutha kuyesa kugwiritsa ntchito njira yosiyana pang'ono, yomwe ili motere. Mwachitsanzo, tikufuna kupeza loko, koma popanda hert zotsatira. Zikhala ndi mfundo yoti ntchito yathu imapempha mndandanda wa ma ID onse a node yomwe ilipo kale yokhala ndi loko. Ndipo ngati izi zisanachitike node yomwe tidapangira loko ndi yaying'ono kwambiri pazomwe tidalandira, ndiye kuti talanda loko. Timayang'ana kuti talandira loko. Monga cheke, padzakhala chikhalidwe kuti id yomwe tidalandira popanga loko yatsopano ndiyochepa. Ndipo ngati tidalandira, ndiye kuti timagwira ntchito mopitilira.
Ngati pali id yocheperako kuposa loko yathu, ndiye kuti timayika wowonera pamwambowu ndikudikirira zidziwitso mpaka china chake chisinthe. Ndiko kuti, tinalandira loko. Ndipo mpaka itagwa, sitidzakhala id yocheperako ndipo sitidzalandira loko yocheperako, motero tidzatha kulowa. Ndipo ngati chikhalidwechi sichinakwaniritsidwe, ndiye kuti nthawi yomweyo timapita kuno ndikuyesanso kupeza loko, chifukwa mwina china chake chasintha panthawiyi.
Kodi ZooKeeper imakhala ndi chiyani? Pali zinthu 4 zazikulu. Izi ndi njira zopangira - Pempho. Komanso ZooKeeper Atomic Broadcast. Pali Commit Log pomwe ntchito zonse zimajambulidwa. Ndipo In-memory Replicated DB yokha, mwachitsanzo, nkhokwe pomwe mtengo wonsewu umasungidwa.
Ndizofunikira kudziwa kuti ntchito zonse zolembera zimadutsa mu Purosesa Yofunsira. Ndipo kuwerenga ntchito kumapita ku In-memory database.
Nawonso database yokhayo yafotokozedwa kwathunthu. Zochitika zonse za ZooKeeper zimasunga deta yonse.
Pofuna kubwezeretsanso database pambuyo pa ngozi, pali Commit log. Mchitidwe wokhazikika ndikuti data isanalowe m'makumbukidwe, imalembedwa pamenepo kuti ikagwa, chipikachi chikhoza kuseweredwanso ndipo dongosolo ladongosolo likhoza kubwezeretsedwanso. Ndipo zithunzi zojambulidwa nthawi ndi nthawi za database zimagwiritsidwanso ntchito.
ZooKeeper Atomic Broadcast ndi chinthu chomwe chimagwiritsidwa ntchito kusunga deta yobwerezedwa.
ZAB mkati imasankha mtsogoleri kuchokera kumalo a ZooKeeper node. Ma node ena amakhala otsatira ake ndipo amayembekeza kuchitapo kanthu kuchokera kwa iye. Ngati alandira zolowa, amatumiza zonse kwa mtsogoleri. Poyamba amalemba ntchito yolemba kenako n’kutumiza uthenga wa zimene zasintha kwa otsatira ake. Izi, kwenikweni, ziyenera kuchitidwa ma atomu, mwachitsanzo, kujambula ndi kuwulutsa kwa chinthu chonsecho kuyenera kuchitidwa ndi atomiki, potero kutsimikizira kusasinthika kwa data.
Amangokonza zopempha zolembera. Ntchito yake yayikulu ndikuti imasintha ntchitoyo kuti ikhale yosinthika. Ili ndi pempho lopangidwa mwapadera.
Ndipo apa ndikofunika kudziwa kuti kusatsimikizika kwa zosintha zamachitidwe omwewo ndizotsimikizika. Ndi chiyani? Chinthu ichi, ngati chikachitidwa kawiri, chidzakhala ndi chikhalidwe chomwecho, mwachitsanzo, pempho lokha silidzasintha. Ndipo izi ziyenera kuchitidwa kuti pakagwa ngozi, mutha kuyambitsanso ntchitoyo, potero mukubweza zosintha zomwe zidagwa pakadali pano. Pankhaniyi, dongosolo la dongosololi lidzakhala lofanana, i.e. siziyenera kukhala choncho kuti mndandanda womwewo, mwachitsanzo, ndondomeko zosinthika, zomwe zinatsogolera ku mayiko osiyanasiyana omaliza a dongosolo.
Source: www.habr.com