ื ืืืืฅ. ืืจืึทื ืกื.: ืื ืก ืคึผืจืึธืืืขื ืืื Kubernetes, ืึธืืขืจ ืืขืจ ืืขื ืื, ืคึผืึทืจืึทืืขืืขืจ ืกืขืืืื ืืก ndots, ืืื ืกืึทืคึผืจืืืืื ืืื ืคืึธืืงืก, ืืื ืฉืืื . ืืื ืื ืื ืืขืจ ืฆืขืื ืืืืฃ ืืขื ืืขืืข, ืืืื ืืืืจ, ืึท ืืขืืืึธืคึผืก ืื ืืฉืขื ืืจ ืคืื ืึท ืืจืืืก ืืจืึธืืงืขืจืืืืฉ ืคืืจืืข ืืื ืื ืืืึท, ืจืขืื ืืืืฃ ืึท ืืืืขืจ ืคึผืฉืื ืืื ืงืึทื ืกืืืก ืฉืืืืืขืจ ืืืขืื ืืืึธืก ืืื ื ืืฆืืง ืคึฟืึทืจ ืงืึธืืขืืขืก ืืืึธืก ืึทืจืืขืื Kubernetes ืฆื ืืืืกื.
ืืืื ืขืจ ืคืื ืื ืืืืคึผื ืืขื ืขืคืืฅ ืคืื ืืืคึผืืืืื ื ืึทืคึผืืึทืงืืืฉืึทื ื ืืืืฃ Kubernetes ืืื ืกืืืืึทืก ืึทืคึผืืึทืงืืืฉืึทื ืืคืืขืงืื ื. ืื ืืจืึท-ืงื ืืื ืื ืืขืจืึทืงืฉืึทื ืืื ืืืืขืจ ืกืืืคึผืืึทืคืืื ืืึทื ืง ืฆื ืื ืกืขืจืืืืก ืืึทืืจืืฃ (), ืืืึธืก ืืื ืึท ืืืืจืืืขื IP ืืืึธืก ืฉืืืฆื ืึท ืกืืื ืคืื ืคึผืึธื IP ืึทืืจืขืกืขืก. ืคึฟืึทืจ ืืืึทืฉืคึผืื, ืืืื ืื ืืื ืกื vanilla ืืืื ืฆื ืงืึธื ืืึทืงื ืื ืืื ืกื chocolate, ืขืก ืงืขื ืขื ืืืืึทื ืึทืงืกืขืก ืื ืืืืจืืืึทื IP ืคึฟืึทืจ chocolate. ืื ืงืฉืื ืขืจืืืืึทื: ืืืขืจ ืืื ืืขื ืคืึทื ืืืขื ืืึทืืื ืื ืื ืก ืืขืื ืฆื chocolate ืืื ืืื?
ืื ืก ื ืึธืืขื ืืึทืืืึธืืข ืืื ืงืึทื ืคืืืืขืจื ืืืืฃ ืึท Kubernetes ืงื ืืื ื ืืฆื . Kubelet ืจืขืืืฉืืกืืขืจื ืึท ืคึผืึธื ืืื CoreDNS ืืื ืึท ื ืึทืืขืกืขืจืืืขืจ ืืื ืืขืงืขืก /etc/resolv.conf ืึทืืข ืคึผืึธืืก. ืืืื ืืืจ ืงืืง ืืื ืื ืืื ืืึทืื /etc/resolv.conf ืงืืื ืคึผืึธื, ืขืก ืืืขื ืงืืงื ืขืคึผืขืก ืืื ืืึธืก:
search hello.svc.cluster.local svc.cluster.local cluster.local
nameserver 10.152.183.10
options ndots:5
ืื ืงืึทื ืคืืืืขืจืืืฉืึทื ืืื ืืขื ืืฆื ืืืจื ืื ืก ืงืืืืึทื ืฅ ืฆื ืคืึธืจืืืก ืจืืงืืืขืก ืฆื ืื ืื ืก ืกืขืจืืืขืจ. ืืื ืืขืงืข resolv.conf ืึผืืื ืื ืคืืืืขื ืืข ืืื ืคึฟืึธืจืืึทืฆืืข:
- ื ืึทืืขืกืขืจืืืขืจ: ืกืขืจืืืขืจ ืฆื ืืืึธืก ืื ืก ืจืืงืืืขืก ืืืขื ืืืื ืืขืฉืืงื. ืืื ืืื ืืืขืจ ืคืึทื, ืืึธืก ืืื ืื ืึทืืจืขืก ืคืื ืื ืงืึธืจืขืื ืก ืืื ืกื;
- ืืืื: ืืืคืืื ื ืื ืืืื ืืจื ืคึฟืึทืจ ืึท ืกืคึผืขืฆืืคืืฉ ืคืขืื. ืขืก ืืื ืืฉืืงืึทืืืข ืึทื
google.comืึธืืขืจmrkaran.devืืขื ืขื ื ืืฉื FQDN (). ืืืื ืื ืกืืึทื ืืึทืจื ืงืึทื ืืืขื ืฉืึทื ืึทื ืจืืึฟ ืื ืก ืจืขืกืึธืืืืขืจื ื ืึธืืืืื, ืืืืื ืื ืืืึธืก ืขื ืืืงื ืืื ืึท ืคึผืื ืงื ".", ืจืขืคึผืจืืืขื ืืื ื ืื ืืืึธืจืฆื ืืึธื ืข, ืืขื ืขื ืืขืจืขืื ื ืืื ืืึธืจ ืงืืืึทืืึทืคืืื (FDQN) ืืึธืืืืื ื. ืขืืืขืืข ืจืืืึทืืืืขืจื ืงืขื ืขื ืืืืื ืึท ืคืื ื ืืื. ืืืื,mrkaran.dev.ืืื ืื ืืึธืจ ืงืืืึทืืึทืคืืื ืคืขืื ื ืึธืืขื (FQDN), ืืืmrkaran.devโ ื ืืื; - ื ืืึธืืก: ืื ืืขืจืกื ืืฉืืงืึทืืืข ืคึผืึทืจืึทืืขืืขืจ (ืืขืจ ืึทืจืืืงื ืืื ืืืขืื ืืื).
ndotsืกืคึผืขืฆืืคืืฆืืจื ืื ืฉืืืขื ื ืืืขืจ ืคืื ืืึทืฅ ืืื ืึท ืืงืฉื ื ืึธืืขื ืืืืืขืจ ืขืก ืืื ืืขืืืืื ืึท "ืืึธืจ ืงืืืึทืืึทืคืืื" ืคืขืื ื ืึธืืขื. ืืืจ ืืืขืื ืจืขืื ืืขืจ ืืืขืื ืืขื ืฉืคึผืขืืขืจ ืืืขื ืืืจ ืึทื ืึทืืืื ืื DNS ืืืงืึทืคึผ ืกืืงืืืึทื ืก.
ืืื ืก ืืขื ืืืึธืก ืืึทืคึผืึทื ื ืืืขื ืืืจ ืคืจืขืื mrkaran.dev ืืื ืคึผืึธื:
$ nslookup mrkaran.dev
Server: 10.152.183.10
Address: 10.152.183.10#53
Non-authoritative answer:
Name: mrkaran.dev
Address: 157.230.35.153
Name: mrkaran.dev
Address: 2400:6180:0:d1::519:6001
ืคึฟืึทืจ ืืขื ืขืงืกืคึผืขืจืืืขื ื, ืืื ืฉืืขืื ืื CoreDNS ืืึธืืื ื ืืืจืื ืฆื all (ืืืึธืก ืืืื ืขืก ืืึทื ืฅ ืืืขืจืืึธืืก). ืืื ืก ืงืืง ืืื ืื ืคึผืึธื ืก ืืึธืืก coredns:
[INFO] 10.1.28.1:35998 - 11131 "A IN mrkaran.dev.hello.svc.cluster.local. udp 53 false 512" NXDOMAIN qr,aa,rd 146 0.000263728s
[INFO] 10.1.28.1:34040 - 36853 "A IN mrkaran.dev.svc.cluster.local. udp 47 false 512" NXDOMAIN qr,aa,rd 140 0.000214201s
[INFO] 10.1.28.1:33468 - 29482 "A IN mrkaran.dev.cluster.local. udp 43 false 512" NXDOMAIN qr,aa,rd 136 0.000156107s
[INFO] 10.1.28.1:58471 - 45814 "A IN mrkaran.dev. udp 29 false 512" NOERROR qr,rd,ra 56 0.110263459s
[INFO] 10.1.28.1:54800 - 2463 "AAAA IN mrkaran.dev. udp 29 false 512" NOERROR qr,rd,ra 68 0.145091744sืคืื. ืฆืืืื ืืืื ืืึทืคึผื ืืืื ืืคืืขืจืงืืึทืืงืืึทื ืืึธ:
- ืื ืืงืฉื ืืืื ืืืจื ืึทืืข ืกืืึทืืขืก ืคืื ืืขืจ ืืืื ืืื ืืขืจ ืขื ืืคืขืจ ืึผืืื ืื ืงืึธื
NOERROR(ืื ืก ืงืืืืึทื ืฅ ืคึฟืึทืจืฉืืืื ืขืก ืืื ืงืจืึธื ืขืก ืืื ืึท ืจืขืืืืืึทื).NXDOMAINืืืื ืึทื ืงืืื ืจืขืงืึธืจื ืืื ืืขืคืื ืขื ืคึฟืึทืจ ืื ืืขืืขืื ืคืขืื ื ืึธืืขื. ืืืืึทื ืืmrkaran.devืืื ื ืืฉื ืึท FQDN ื ืึธืืขื (ืืืืndots=5), ืจืขืกืึธืืืืขืจ ืงืืงื ืืืืฃ ืื ืืืื ืืจื ืืื ืืืืขืจืืึทื ื ืื ืกืืจ ืคืื ืจืืงืืืขืก; - ืึทืจืืืงืืขื
ะะธะะะะืึธื ืงืืืขื ืืื ืคึผืึทืจืึทืืขื. ืืขืจ ืคืึทืงื ืืื ืึทื ืืืื ืืึธื ืจืืงืืืขืก ืืื/etc/resolv.confืืืจื ืคืขืืืงืืึทื, ืืื ืืขื ืขื ืงืึทื ืคืืืืขืจื ืืื ืึทืืึท ืึท ืืืขื ืึทื ืคึผืึทืจืึทืืขื ืึธื ืคึฟืจืขืื ืืขื ืขื ืืืจืืืขืงืึธืื ืืื ืื IPv4 ืืื IPv6 ืคึผืจืึธืืึธืงืึธืืก. ืืืจ ืงืขื ืขื ืืึธืื ืืึทืื ืืขื ื ืึทืืืจ ืืืจื ืึทืืื ื ืื ืึธืคึผืฆืืขsingle-requestะฒresolv.conf.
ืืึทืืขืจืงืื ื: glibc ืงืขื ืขื ืืืื ืงืึทื ืคืืืืขืจื ืฆื ืฉืืงื ืื ืจืืงืืืขืก ืกืึทืงืืืขื ืืฉืึทืื, ืืื musl ื ืืื, ืึทืืื ืึทืืคึผืืื ื ืืฆืขืจืก ืืึธื ื ืขืืขื ืืึธื.
ืขืงืกืคึผืขืจืืืขื ืืื ื ืืื ื ืืึธืืก
ืืื ืก ืขืงืกืคึผืขืจืืืขื ื ืึท ืืืกื ืืขืจ ืืื ndots ืืื ืืึธืืืจ ืืขื ืืื ืืขืจ ืคึผืึทืจืึทืืขืืขืจ ืืืืืืืื. ืืขืจ ืืขืืึทื ืง ืืื ืคึผืฉืื: ndots ืืืืขืจืืึทื ื ืฆื ืืขืจ ืื ืก ืงืืืขื ื ืืืขื ืืืึทืื ืื ืคืขืื ืืื ืึทืืกืึธืืื ืึธืืขืจ ืงืึธืจืขืื. ืคึฟืึทืจ ืืืึทืฉืคึผืื, ืืื ืืขื ืคืึทื ืคืื ืึท ืคึผืฉืื Google DNS ืงืืืขื ื, ืืื ืงืขื ืขืก ืืืืกื ืืืื ืืขื ืคืขืื ืืื ืึทืืกืึธืืื? ืืืื ืืืจ ืฉืืขืื ndots ืืืืื ืฆื 1, ืืขืจ ืงืืืขื ื ืืืขื ืืึธืื: "ืึธื, ืืื google ืขืก ืืื ื ืืฉืืึธ ืงืืื ืืืื ืคืื ื; ืืื ืจืขืื ืืื ืืืขื ืืืจืืืืื ืื ืืื ืฆืข ืืื ืจืฉืืื. โ ืึธืืขืจ, ืืืื ืืืจ ืคืจืขืื google.com, ืื ืจืฉืืื ืคืื ืกืึทืคืืงืกืื ืืืขื ืืืื ืืึธืจ ืืืื ืึธืจืืจื ืืืืึทื ืื ืืขืืขืื ื ืึธืืขื ืืจืขืคื ืื ืฉืืืขื ndots (ืขืก ืืื ืืคึผืืืช ืืืื ืคืื ื).
ืืื ืก ืืึทืื ืืืืขืจ ืคืื ืืขื:
$ cat /etc/resolv.conf
options ndots:1
$ nslookup mrkaran
Server: 10.152.183.10
Address: 10.152.183.10#53
** server can't find mrkaran: NXDOMAINCoreDNS ืืึธืืก:
[INFO] 10.1.28.1:52495 - 2606 "A IN mrkaran.hello.svc.cluster.local. udp 49 false 512" NXDOMAIN qr,aa,rd 142 0.000524939s
[INFO] 10.1.28.1:59287 - 57522 "A IN mrkaran.svc.cluster.local. udp 43 false 512" NXDOMAIN qr,aa,rd 136 0.000368277s
[INFO] 10.1.28.1:53086 - 4863 "A IN mrkaran.cluster.local. udp 39 false 512" NXDOMAIN qr,aa,rd 132 0.000355344s
[INFO] 10.1.28.1:56863 - 41678 "A IN mrkaran. udp 25 false 512" NXDOMAIN qr,rd,ra 100 0.034629206s
ืืื ื ืืื mrkaran ืขืก ืืื ื ืืฉื ืึท ืืืื ืคืื ื, ืื ืืืื ืืื ืืืจืืืขืงืึธืื ืืืืขืจ ืื ืืื ืฆืข ืจืฉืืื ืคืื ืกืึทืคืืงืก.
ืืึทืืขืจืงืื ื: ืืื ืคืืจ ืื ืืึทืงืกืืืื ืืืขืจื ndots ืืืืจืขื ืขืฆื ืฆื 15; ืืืจื ืคืขืืืงืืึทื ืืื Kubernetes ืขืก ืืื 5.
ืึทืคึผืคึผืืืงืึทืืืึธื ืืื ืคึผืจืึธืืืงืฆืืข
ืืืื ืึท ืึทืคึผืืึทืงืืืฉืึทื ืืืื ืึท ืคึผืืึทืฅ ืคืื ืคืื ืืจืืืกื ืืืง ื ืขืฅ ืงืึทืืืก, DNS ืงืขื ืขื ืืืขืจื ืึท ืืึทืืึทืื ืขืง ืืื ืืขื ืคืึทื ืคืื ืึทืงืืืื ืคืึทืจืงืขืจ, ืืืืึทื ื ืึธืืขื ืืึทืืืึธืืข ืืืื ืคืืืข ืืื ืืืืืง ืคึฟืจืืื (ืืืืืขืจ ืื ืกืืกืืขื ืงืืื ืฆื ืื ืจืขืื ืืืื ืขืจ). ืึทืคึผืคึผืืืงืึทืืืึธื ืก ืืืืฉืึทืืืึทืื ืืึธื ื ืื ืืืืื ืึท ืืืึธืจืฆื ืืึธื ืข ืฆื ืคืขืื ื ืขืืขื, ืึธืืขืจ ืืึธืก ืกืึธืื ืืก ืืื ืึท ืืึทืง. ืืึธืก ืืฒืกื, ืึทื ืฉืืึธื ืคึฟืจืขืื api.twitter.com, ืืืจ ืงืขื ืขื 'ืืึทืจืืงืึธืืข' ืขืก api.twitter.com. (ืืื ืึท ืคึผืื ืงื) ืืื ืื ืึทืคึผืืึทืงืืืฉืึทื, ืืืึธืก ืืืขื ืืขืื ืื ืก ืงืืืืึทื ืฅ ืฆื ืืืจืืคืืจื ืึทืืึธืจืึทืืืืืืื ืืืงืึทืคึผืก ืืืืึทื ืืืืฃ ืื ืึทืืกืึธืืื ืคืขืื.
ืึทืืืืืืึธื ืึทืืื, ืกืืึทืจืืื ื ืืื Kubernetes ืืืขืจืกืืข 1.14, ืืงืกืืขื ืฉืึทื ื dnsConfig ะธ dnsPolicy ืืืงืืืขื ืกืืึทืืื ืกืืึทืืืก. ืืืื, ืืืขื ืืืคึผืืืืื ื ืึท ืคึผืึธื, ืืืจ ืงืขื ืขื ืจืขืืืฆืืจื ืื ืืืขืจื ndots, ืืึธืื, ืึทืจืืืฃ ืฆื 3 (ืืื ืืคืืื ืึทืจืืืฃ ืฆื 1!). ืืืืึทื ืคืื ืืขื, ืืขืืขืจ ืึธื ืืึธื ืืื ืึท ื ืึธืืข ืืืขื ืืึธืื ืฆื ืึทืจืืึทื ื ืขืืขื ืื ืคืื ืคืขืื. ืืึธืก ืืื ืืืื ืขืจ ืคืื ืื ืงืืึทืกืืฉ ืืึทื ืื-ืึธืคืก ืืืขื ืืืจ ืืึธืื ืฆื ืงืืืึทืื ืฆืืืืฉื ืคืึธืจืฉืืขืืื ื ืืื ืคึผืึธืจืืึทืืืืืื. ืขืก ืืืื ื ืฆื ืืืจ ืึทื ืืืจ ืืึธื ืืึธืจื ืืืขืื ืืขื ืืืืื ืืืื ืืื ืืขืจ-ื ืืืขืจืืง ืืืืืึทื ืกื ืืื ืืืืืึทื ืคึฟืึทืจ ืืืื ืึทืคึผืืึทืงืืืฉืึทื, ืืืืึทื ืื DNS ืจืขืืืืืึทืื ืืขื ืขื ืืืื ืงืึทืฉื ืื ืขืืืืื ืืง.
ืจืขืคึฟืขืจืขื ืฆื
ืืื ืขืจืฉืืขืจ ืืขืืขืจื ื ืืืขืื ืืขื ืฉืืจืื ืืืืฃ , ืคืืจื ืืืขื ืืขื 25ืื ืืื ืืืจ. ืขืก ืืื ืืขืืืขื ืึท ืืืกืงืืกืืข ืืืขืื ืืขื ืคึผืจืึธืืืขื, ืฆืืืืฉื ืื ืืขืจืข ืืืื.
ืืึธ ืืขื ืขื ืขืืืขืืข ืืื ืงืก ืคึฟืึทืจ ืืืืึทืืขืจ ืืืกืคืึธืจืฉืื ื:
- , ืคืืจืฐืื ื ืืืืก=5 ืืื ืงืืืขืจื ืขืืขืก;
- ืืื ืืฉืึทื ืืื ื ื ืืึทืฅ ืึทืคืขืงืฅ ืึทืคึผืืึทืงืืืฉืึทื ืคืึธืจืฉืืขืืื ื;
- ืฆืืืืฉื Musl ืืื Glibc ืจืขืกืึธืืืืขืจืก.
ืืึทืืขืจืงืื ื: ืืื ืืืืกืืขืจืืืืืื ื ืืฉื ืฆื ื ืืฆื dig ืืื ืืขื ืึทืจืืืงื. dig ืืืืืึธืืึทืืืฉ ืืืกืืฃ ืึท ืคึผืื ืงื (ืืืึธืจืฆื ืืึธื ืข ืืืขื ืืืคืืขืจ), ืืืื ืื ืคืขืื "ืืึธืจ ืงืืืึทืืึทืคืืื" (FQDN), ืงืืื ืืืจื ืขืจืฉืืขืจ ืืืืคื ืขืก ืืืจื ืื ืืืื ืจืฉืืื. ืืขืฉืจืืื ืืืขืื ืืขื ืืื . ืึธืืขืจ, ืขืก ืืื ืืึทื ืฅ ืืืืืฉ ืึทื, ืืื ืึทืืืขืืืื, ืึท ืืึทืืื ืืขืจ ืคืึธื ืืืื ืืืื ืกืคึผืขืกืืคืืขื ืคึฟืึทืจ ื ืึธืจืืึทื ื ืึทืืืจ.
ืืื ืื ืกืื ื! ืืขื ืืืขื ืืื ืืขืื!
ืคึผืก ืคืื ืืืืขืจืืขืฆืขืจ
ืืืืขื ืขื ืืืื ืืืืฃ ืืื ืืืขืจ ืืืึธื:
- ยซ";
- ยซ";
- "ืึทื ืืืืืกืืจืึทืืขื ืืืื ืฆื ื ืขืืืืึธืจืงืื ื ืืื ืงืืืขืจื ืขืืขืก": , .
ืืงืืจ: www.habr.com