Mhoro, Habr! Ndinokupa kutariswa kweshanduro yechinyorwa naAndrew Beekhof.
Vanhu vazhinji vanosarudza maviri-node masumbu nekuti anoita senge akareruka uye zvakare akachipa 33% pane avo matatu-node mamwe. Kunyange zvazvo zvichikwanisika kuisa pamwe chete boka rakanaka remanodhi maviri, kazhinji, nekuda kwezviitiko zvisingatarisirwi, kugadzirisa kwakadaro kuchagadzira matambudziko akawanda asingaonekwi.
Nhanho yekutanga yekugadzira chero yakakwirira kuwanikwa system ndeye kutsvaga uye kuedza kubvisa ega mapoinzi ekutadza, anowanzo kupfupikiswa se SPoF (imwe pfungwa yekukundikana).
Zvakakosha kuyeuka kuti hazvibviri kubvisa zvose zvingaita njodzi dzenguva yekuderera mune chero hurongwa. Izvi zvinobva pachokwadi chekuti chidziviriro chinopesana nenjodzi ndechekuunza imwe redundancy, izvo zvinotungamira kune yakawedzera kuoma kwehurongwa uye kubuda kwemapoinzi matsva ekutadza. Nokudaro, isu tinotanga kuita kubvumirana uye kutarisa kune zviitiko zvine chokuita nemafungiro ega ega ekukundikana, uye kwete pamaketani ane hukama uye, naizvozvo, kuwedzera zvishoma zvingangoitika zviitiko.
Tichifunga nezvekutengeserana, isu hatitarise SPoF chete, asiwo kuenzanisa njodzi nemhedzisiro, semugumisiro wekuti mhedziso yezvakakosha uye izvo zvisiri izvo zvinogona kusiyana pane imwe neimwe yekutumirwa.
Haasi munhu wese anoda mamwe vatengesi vemagetsi vane tambo dzemagetsi dzakazvimirira. Kunyangwe iyo paranoia yakabhadhara kune angangoita mutengi mumwechete apo kutarisisa kwavo kwakaona kutadza kushandura. Mutengi akafona achiedza kuzivisa kambani yemagetsi kusvika iyo transformer yaputika.
Nzvimbo yekutanga yekutanga kuve neinodarika node imwe muhurongwa. Nekudaro, iyo system isati yagona kufambisa masevhisi kune inosara node mushure mekutadza, inowanzoda kuona kuti masevhisi ari kutamiswa haasi kushanda kumwe kunhu.
Iko hakuna kuderera kune maviri-node cluster kana kutadza kuchizoguma mune ese node inoshumira yakafanana static webhusaiti. Nekudaro, zvinhu zvinoshanduka kana mhedzisiro yacho iri yekuti mapato ese ari maviri akazvimiririra anodzora mutsara webasa rakagovaniswa kana kupa isina kurongeka yekunyora kuwana kune yakadhindwa dhatabhesi kana yakagovaniswa faira system.
Naizvozvo, kudzivirira huwori hwe data semugumisiro wekukundikana kwenodhi imwe chete - tinovimba nechimwe chinhu chinonzi "dissociation" (fencing).
The musimboti dissociation
Pamwoyo weiyo musimboti wekuparadzanisa mubvunzo: iyo node inokwikwidza inogona kukonzera huwori hwe data here? Kana huwori hwe data huchingoitika, mhinduro yakanaka ingave yekuparadzanisa node kubva kune zvese zvinouya zvikumbiro uye kuramba kuchichengeta. Nzira inonyanyozivikanwa yekuzviparadzanisa ndeyekubvisa ma node asina kunaka.
Pane zvikwata zviviri zvedissociation nzira, dzandichadaidza zvakananga ΠΈ zvisina kunanga, asi vanogona kudanwa zvakaenzana active ΠΈ passive. Nzira dzakananga dzinosanganisira zviito zvevezera vachiri vapenyu, sekudyidzana neIPMI (Intelligent Platform Management Interface) kana iLO (magadzirirwo ekugadzirisa maseva pasina kuwanikwa kwemuviri kwavari) mudziyo, nepo nzira dzisina kunanga dzichitsamira pane yakakundikana. node yekuziva neimwe nzira kuti iri munzvimbo isina hutano (kana kuti kudzivirira dzimwe nhengo kupora) uye chiratidzo. nezvechido chekubvisa node yakakundikana.
Quorum inobatsira kana uchishandisa nzira dzese dzakananga uye dzisina kunanga.
Kuparadzana kwakananga
Panyaya yekuparadzana kwakananga, tinogona kushandisa quorum kudzivirira mijaho yekuparadzana kana paine kutadza kwetiweki.
Nepfungwa yequorum, kune ruzivo rwakakwana muhurongwa (kunyangwe pasina kubatana kune vezera rayo) kuti node dzizive otomatiki kana dzichifanira kutanga kuparadzanisa uye / kana kupora.
Pasina quorum, mativi ese ari maviri etiweki kupatsanurwa anozofunga kuti imwe yafa uye ichatsvaga kuparadzanisa imwe. Munyaya yakaipisisa, mapato ese ari maviri anokwanisa kuvhara sumbu rese. Imwe mamiriro ezvinhu ndeyekufa, kusingaperi kusingaperi kwenode kubereka, kusaona vezera ravo, kuvatangazve, uye kutanga kupora chete kuti vatangezve kana vezera ravo vachitevera pfungwa imwe chete.
Dambudziko rekuzviparadzanisa nderekuti michina inonyanya kushandiswa inove isingawanikwe nekuda kwezvimwe zviitiko zvekutadza izvo zvatinoda kunanga kupora. Mazhinji IPMI neILO makadhi akaiswa pane anotambira avanotonga uye, nekukasira, shandisa network imwe chete, izvo zvinoita kuti vanotariswa vatende kuti mamwe mauto ari offline.
Nehurombo, maficha ekushandisa eIPMI uye iLo zvishandiso haawanzo kutariswa panguva yekutenga michina.
Indirect dissociation
Quorum yakakoshawo kubata zvisina kunanga disassociation; kana ikaitwa nemazvo, quorum inogona kubvumira vanopona kuti vafunge kuti akarasika node anozochinja kuenda kunzvimbo yakachengeteka mushure meimwe nguva yenguva.
Nekumisikidzwa uku, iyo hardware watchdog timer inogadzwa patsva ese N masekonzi kana quorum isina kurasika. Kana iyo timer (kazhinji akawanda akawanda eN) apera, ipapo mudziyo unoita isingafadzi simba pasi (kwete kudzima).
Iyi nzira inoshanda zvakanyanya, asi pasina quorum hapana ruzivo rwakakwana mukati mechikwata chekuchibata. Hazvisi nyore kutaura mutsauko pakati pekudzima network nekutadza kwevezera node. Chikonzero nei ichi chakakosha ndechekuti pasina kugona kusiyanisa pakati pezviitiko zviviri izvi, unomanikidzwa kusarudza maitiro akafanana mune ese ari maviri.
Dambudziko nekusarudza imwe modhi nderekuti hapana nzira yekuita iyo inowedzera kuwanikwa uye inodzivirira kurasikirwa kwedata.
- Kana ukasarudza kufungidzira kuti peer node inoshanda asi ichitadza, sumbu racho rinomisa zvisina basa masevhisi anenge achimhanya kutsiva kurasikirwa kwesevhisi kubva kune yakundikana peer node.
- Kana iwe ukafunga kufunga kuti node iri pasi, asi kwaingove kutadza kwetiweki uye kutaura zvazviri nzvimbo iri kure inoshanda, saka zvakanakisa iwe uri kusaina kune imwe ramangwana remanyore kuyananiswa kwezvakaguma data seti.
Zvisinei nekuti chii chaunoshandisa heuristic, hazvina basa kugadzira kukundikana kunokonzeresa kuti mativi ese ari maviri atadze kana kuita kuti cluster ivhare node dzakasara. Kusashandisa quorum zvechokwadi kunobvisa sumbu rechimwe chezvishandiso zvine simba mudura rayo.
Kana pasina imwe nzira, nzira yakanakisa ndeyekupira kuwanikwa (pano munyori anoreva iyo CAP theorem). Kuwanikwa kwepamusoro kwe data yakaora hakubatsiri chero munhu, uye kuyananisa ma data akasiyana-siyana hakunakidze.
Quorum
Quorum inonzwika zvakanaka, handiti?
Chinongodzikira chete ndechekuti kuti uve nacho musumbu nenhengo dzeN, unofanirwa kuve nekubatana pakati peN/2+1 yemanode ako asara. Izvo zvisingagoneke mune mbiri node cluster mushure mekunge imwe node yatadza.
Izvo zvinozopedzisira zvatisvitsa kudambudziko rakakosha nemanode maviri:
Quorum haina musoro mumasumbu maviri emanodhi, uye pasina iyo hazvigoneke kuona nekuvimbika nzira yekuita iyo inowedzera kuwanikwa uye inodzivirira kurasikirwa kwedata.
Kunyangwe muhurongwa hwemanodhi maviri akabatana netambo yecrossover, hazvibviri kunyatsosiyanisa pakati pekudzima network uye kutadza kweimwe node. Kuvhara imwe mugumo (mukana wekuti, hongu, wakaenzana nechekure pakati pemanodhi) ichave yakakwana kukanganisa chero fungidziro yekuti hutano hwekubatanidza hwakaenzana nehutano hwemudiwa node.
Kuita maviri-node cluster basa
Dzimwe nguva mutengi haagone kana kuti haadi kutenga yechitatu node, uye isu tinomanikidzwa kutsvaga imwe nzira.
Sarudzo 1 - Duplicate dissociation nzira
Iyo node's iLO kana IPMI mudziyo unomiririra poindi yekutadza nekuti, kana ikatadza, vanopona havagone kuishandisa kuunza node kunzvimbo yakachengeteka. Mune sumbu rematatu kana anopfuura node, tinogona kudzikisira izvi nekuverenga quorum uye kushandisa hardware watchdog (imwe isina kunanga disassociation mechanism, sezvakakurukurwa pakutanga). Panyaya yemanodhi maviri, isu tinofanirwa kushandisa network simba rekugovera zvikamu (PDUs) pachinzvimbo.
Mushure mekutadza, mupukunyuki anotanga aedza kubata mudziyo wekutanga wekubvisa (yakaiswa iLO kana IPMI). Kana izvi zvikabudirira, kupora kunoenderera semazuva ese. Chete kana iyo iLO/IPMI mudziyo ikakundikana ndiyo PDU inowanikwa; kana kuwana kwacho kwakabudirira, kupora kunogona kuenderera.
Iva neshuwa yekuisa iyo PDU pane yakasiyana network pane iyo cluster traffic, zvikasadaro imwe kutadza kwetiweki kuchavhara kupinda kune ese ari maviri madhizaini ekuparadzanisa uye kuvharira kudzoreredzwa kwemasevhisi.
Pano iwe unogona kubvunza - iyo PDU ipfungwa imwe yekutadza here? Kune iyo mhinduro, hongu ndizvo.
Kana njodzi iyi yakakosha kwauri, hausi wega: batanidza node mbiri kune maPDU maviri uye taurira iyo clustering software kuti ishandise ese ari maviri pakusimbisa node nekudzima. Iyo cluster ikozvino inoramba ichishanda kana imwe PDU ikafa, uye kutadza kwechipiri kweimwe PDU kana iyo IPMI mudziyo unozodikanwa kuvhara kupora.
Sarudzo 2 - Kuwedzera Arbiter
Mune zvimwe zviitiko, nepo nzira yekuparadzanisa inogoneka nehunyanzvi, yakaoma mune zvematongerwo enyika. Makambani mazhinji anoda kuve nekuparadzaniswa pakati pevatariri uye varidzi vezvishandiso, uye chengetedzo-vanoziva network maneja havawanzo kufarira kugovera PDU magadzirirwo ekuwana chero munhu.
Muchiitiko ichi, inokurudzirwa imwe nzira ndeyekugadzira munhu asina kwaakarerekera wechitatu anogona kuwedzera quorum calculation.
Muchiitiko chekukundikana, node inofanira kukwanisa kuona airwaves yevezera rayo kana arbiter kuitira kuti idzorere mabasa. Iyo arbiter inosanganisirawo basa rekubvisa kana node mbiri dzichikwanisa kuona arbiter asi dzisingakwanisi kuonana.
Iyi sarudzo inofanira kushandiswa pamwe chete nenzira isina kunanga yekuparadzanisa, senge hardware watchdog timer, iyo inogadzirirwa kuuraya muchina kana ikarasikirwa nekubatana kune vezera rayo uye arbiter node. Saka, mupukunyuki anogona kufunga zvine musoro kuti peer node yake ichange iri munzvimbo yakachengeteka mushure mekunge hardware watchdog timer yapera.
Musiyano unoshanda pakati pearbiter neyechitatu node ndewekuti arbiter inoda zviwanikwa zvishoma kuti ishande uye inogona kushandira anopfuura sumbu rimwe.
Sarudzo 3 - Chinhu chevanhu
Maitiro ekupedzisira ndeekuti vanopona vaenderere mberi vachimhanyisa chero masevhisi avanga vachitoita, asi kwete kutanga matsva kusvika dambudziko razvigadzirisa pacharo (network kudzoreredza, node reboot) kana munhu anotora basa rekusimbisa nemaoko kuti rimwe divi rafa.
Bonus sarudzo
Ndataura here kuti unogona kuwedzera node yechitatu?
Raka mbiri
Nekuda kwekukakavadzana, ngatiite senge ini ndakutendisai nezvekukodzera kwenodhi yechitatu, ikozvino isu tinofanira kufunga nezve kurongeka kwemuviri kwemanodhi. Kana ivo vakagarwa (uye vachipihwa simba) mune imwechete rack, izvi zvakare zvinosanganisira SPoF, uye imwe isingagone kugadziriswa nekuwedzera yechipiri rack.
Kana izvi zvichishamisa, funga kuti chii chingaitika kana rack ine node mbiri ikatadza, uye kuti node yasara ingasiyanisa sei pakati peiyo nekutadza kwetiweki.
Mhinduro pfupi ndeyokuti izvi hazvigoneki, uye isu tiri kutarisana zvakare nematambudziko ose munyaya ye node mbiri. Kana mupukunyuki:
- inofuratira quorum uye ichiedza zvisizvo kutanga kudzoreredza panguva yekudzima network (kukwanisa kupedzisa kuparadzaniswa inyaya yakasiyana uye zvinoenderana nekuti PDU inobatanidzwa uye kana vachigovana simba nechero racks), kana
- inoremekedza quorum uye inozvibvisa pachayo nguva isati yakwana kana imwe node yezera yakundikana
Chero zvazvingaitika, maraki maviri haasi nani pane imwe, uye nodhi dzinofanirwa kugamuchira yakazvimirira magetsi ekushandisa kana kugoverwa kune matatu (kana kupfuura, zvichienderana nekuti ingani node dzaunadzo) racks.
Nzvimbo mbiri dze data
Panguva ino, vaverengi vasisiri njodzi vanogona kuda kufunga nezvekugadzirisa njodzi. Chii chinoitika kana asteroid ikarova nzvimbo imwechete yedata nemanodhi edu matatu akapararira mumaraki matatu akasiyana? Zviripachena Zvinhu Zvakaipa, asi zvichienderana nezvido zvako, kuwedzera yechipiri data data kungasave kwakakwana.
Kana zvikaitwa nemazvo, yechipiri dhata nzvimbo inokupa iwe (uye zvine musoro kudaro) ine yemazuva ano uye inowirirana kopi yemasevhisi ako uye data ravo. Nekudaro, senge mune mbiri-node, maviri-rack scenario, hapana ruzivo rwakakwana musystem kuti ive nechokwadi chekuwanikwa kwakanyanya uye kudzivirira huwori (kana data set kusawirirana). Kunyangwe nemanodhi matatu (kana marekeni), kuagovera munzvimbo mbiri chete dzedata kunosiya sisitimu isingakwanise kuita sarudzo chaiyo kana chiitiko (ikozvino chanyanya kuitika) chiitiko icho mapato ese ari maviri haagone kutaurirana.
Izvi hazvireve kuti dual data center solution haina kumbokodzera. Makambani anowanzoda kuti munhu azive asati atora danho rinoshamisa rekuenda kunzvimbo yekuchengetedza data. Ingo yeuka kuti kana iwe uchida kushandura kubuda, iwe ungangoda yechitatu data data yequorum kuti iite zvine musoro (zvichida zvakananga kana kuburikidza neanopikisa), kana iwe uchawana nzira yekuvharisa nekuvimbika data rese. centre.
Source: www.habr.com