/etc/resolv.conf kuma-Kubernetes pods, i-ndots:inketho engu-5, lokhu kungaba nomthelela omubi kanjani ekusebenzeni kohlelo lokusebenza

Sisanda kwethula i-Kubernetes 1.9 ku-AWS sisebenzisa i-Kops. Izolo, ngenkathi ngikhipha ithrafikhi entsha ngokushelelayo kumaqoqo ethu amakhulu e-Kubernetes, ngiqale ukuqaphela amaphutha angajwayelekile wokuxazulula amagama e-DNS afakwe uhlelo lwethu lokusebenza.

Kuningi kakhulu ngalokhu ku-GitHub wakhuluma, ngakho nami nganquma ukukucacisa. Ekugcineni, ngabona ukuthi esimweni sethu lokhu kubangelwa umthwalo owandayo kube-dns и dnsmasq. Into ethakazelisa kakhulu nentsha kimi kwakuyisona sizathu sokwanda okukhulu kwethrafikhi yesicelo se-DNS. Okuthunyelwe kwami ​​kumayelana nalokhu nokuthi ngenzenjani ngakho.

Ukulungiswa kwe-DNS ngaphakathi kwesiqukathi - njengakunoma iyiphi isistimu ye-Linux - kunqunywa ifayela lokumisa /etc/resolv.conf. Okuzenzakalelayo Kubernetes dnsPolicy lokhu kungukuthi ClusterFirst, okusho ukuthi noma yisiphi isicelo se-DNS sizothunyelwa dnsmasq, egijima esidunjini kube-dns ngaphakathi kweqoqo, elizodlulisela isicelo kuhlelo lokusebenza kube-dns, uma igama ligcina ngesijobelelo seqoqo, noma, ngaphandle kwalokho, liye ezingeni eliphezulu leseva ye-DNS.

Файл /etc/resolv.conf ngaphakathi kwesiqukathi ngasinye okuzenzakalelayo kuzobukeka kanje:

nameserver 100.64.0.10
search namespace.svc.cluster.local svc.cluster.local cluster.local 
eu-west-1.compute.internal
options ndots:5

Njengoba ubona, kuneziqondiso ezintathu:

1. Igama leseva yi-IP yesevisi kube-dns
2. 4 izizinda zokusesha zendawo ezicacisiwe search
3. Kukhona inketho ndots:5

Ingxenye ethokozisayo yalokhu kumisa ukuthi izizinda zosesho lwasendaweni kanye nezilungiselelo ndots:5 nizwane. Ukuze uqonde lokhu, udinga ukuqonda ukuthi isixazululo se-DNS samagama angafaneleki sisebenza kanjani.

Lithini igama eligcwele?

Igama elifaneleke ngokugcwele igama okungekho ukubhekwa kwalo kwendawo okuzokwenziwa futhi igama lizobhekwa njengeliphelele ngesikhathi sokulungiswa kwegama. Ngokwesimiso, isofthiwe ye-DNS ibheka igama njengelifaneleke ngokugcwele uma ligcina ngechashazi (.), futhi lingafaneleki ngokugcwele ngenye indlela. Leyo google.com. kuchazwe ngokugcwele futhi google.com - Cha.

Liphathwa kanjani igama elingafaneleki?

Uma uhlelo lokusebenza luxhumeka kumsingathi wesilawuli kude esishiwo egameni, ukulungiswa kwegama le-DNS ngokuvamile kwenziwa kusetshenziswa ikholi yesistimu, isb. getaddrinfo(). Kodwa uma igama lingafaneleki (aligcini ngokuthi.) Ngiyazibuza ukuthi uma ikholi yesistimu izozama ukuxazulula igama njengegama eliphelele kuqala, noma idlule ezizindeni zokusesha zasendaweni kuqala? Kuya ngenketho ndots.

Kusukela kumanuwali resolv.conf:

ndots:n

устанавливает порог для количества точек, которые должны появиться в имени, прежде чем будет сделан начальный абсолютный запрос. Значение по умолчанию для n равно 1, что означает, что если в имени есть какие-либо точки, имя будет сначала опробовано как абсолютное имя, прежде чем к нему будут добавлены какие-либо элементы списка поиска.

Lokhu kusho ukuthi uma for ndots uma kunikezwe inani elingu-5 futhi igama liqukethe amachashazi angaphansi kuka-5, ikholi yesistimu izozama ukuyixazulula ngokulandelana, kuqala inqamule zonke izizinda zokusesha zendawo, futhi, uma kuhlulekile, ekugcineni ixazulule njengegama eliphelele.

Kungani pho ndots:5 kungaba nomthelela omubi ekusebenzeni kohlelo lokusebenza?

Njengoba ungacabanga, uma uhlelo lwakho lokusebenza lisebenzisa ithrafikhi eningi yangaphandle, kukho konke ukuxhumana kwe-TCP okusungulwe (noma ngokunembe kakhulu, kuwo wonke amagama axazululiwe), izokhipha imibuzo emi-5 ye-DNS ngaphambi kokuthi igama lixazululwe kahle, ngoba lizoqala lidlule. 4 isizinda sokusesha sendawo, futhi ekugcineni sizokhipha isicelo sokuxazulula igama ngokuphelele.

Ishadi elilandelayo libonisa inani lethrafikhi kumamojula wethu we-kube-dns angu-3 ngaphambi nangemuva kokuthi sishintshe amagama omethuleli ambalwa amiswe kuhlelo lwethu lokusebenza ukuba afaneleke ngokugcwele.

Umdwebo olandelayo ubonisa ukubambezeleka kohlelo lokusebenza ngaphambi nangemuva kokuthi sishintshe amagama omethuleli amaningana amisiwe kuhlelo lwethu lokusebenza abe amagama aphelele (umugqa oluhlaza okwesibhakabhaka oqondile uwukusetshenziswa):

Isixazululo #1 - Sebenzisa amagama afaneleke ngokugcwele

Uma unamagama ambalwa angaphandle amile (okungukuthi achazwe ekucushweni kohlelo lokusebenza) owakha kuwo inqwaba yokuxhumana, mhlawumbe isisombululo esilula ukuwashintshela kwabafaneleke ngokugcwele ngokumane uwahlanganise. ekugcineni.

Lesi akusona isixazululo sokugcina, kodwa kusiza ukushesha, nakuba hhayi ngokuhlanzekile, ukuthuthukisa isimo. Sisebenzise lesi siqeshana ukuze sixazulule inkinga yethu, imiphumela yayo eboniswe kuzithombe-skrini ezingenhla.

Isixazululo #2 - ukwenza ngokwezifiso ndots в dnsConfig

Ku-Kubernetes 1.9, ukusebenza kuvele kumodi ye-alpha (inguqulo ye-beta v1.10), ekuvumela ukuthi ulawule kangcono amapharamitha e-DNS ngesakhiwo se-pod dnsConfig. Phakathi kwezinye izinto, ikuvumela ukuthi ulungiselele inani ndots nge-pod ethile, i.e.

apiVersion: v1
kind: Pod
metadata:
  namespace: default
  name: dns-example
spec:
  containers:
    - name: test
      image: nginx
  dnsConfig:
    options:
      - name: ndots
        value: "1"

Imithombo

• Kuyini ukufaneleka kwegama le-DNS
• I-Kubernetes: I-DNS Yamasevisi nama-Pods

Funda nezinye izindatshana kubhulogi yethu:

• Ukuqonda iphakheji Yokuqukethwe ngesi-Golang
• Amaqhinga Amathathu Alula Wokunciphisa Izithombe Ze-Docker
• Izipele ezisemthethweni ku-Kubernetes
• Isipele senani elikhulu lamaphrojekthi ewebhu ahlukahlukene
• I-Telegraph bot ye-Redmine. Ungayenza kanjani impilo ibe lula kuwe nakwabanye

Source: www.habr.com