Tenho 2 contêineres em execução no mesmo namespace.
- DNS no pod do podxwingnão resolve o nome do host, mas resolverá o FQDN
- masDNS no pod do podútilresolvê-lo corretamente.
✗ kgpo
NAME READY STATUS RESTARTS AGE
deathstar-7848d6c4d5-g248j 1/1 Running 0 15m
deathstar-7848d6c4d5-qnsp8 1/1 Running 0 15m
tiefighter 1/1 Running 0 15m
utils 1/1 Running 0 11m
xwing 1/1 Running 0 15m
➜ kgsvc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
deathstar ClusterIP 172.20.41.112 <none> 80/TCP 15m
kubernetes ClusterIP 172.20.0.1 <none> 443/TCP 46d
➜ k ice image
PODNAME CONTAINER PULL IMAGE TAG
deathstar-7848d6c4d5-g248j deathstar Always docker.io/cilium/starwars -
deathstar-7848d6c4d5-qnsp8 deathstar Always docker.io/cilium/starwars -
tiefighter spaceship Always docker.io/tgraf/netperf -
utils utils Always saritasallc/network-multitool -
xwing spaceship Always docker.io/tgraf/netperf -
os seguintes pods:
- xwing
(docker.io/tgraf/netperf)e - útil
(saritasallc/network-multitool)
os pods mostram os mesmos /etc/resolv.confvalores, mas se comportam de maneira diferente para nslookupconsulta.
➜ kex xwing -- cat /etc/resolv.conf
search default.svc.cluster.local svc.cluster.local cluster.local ec2.internal
nameserver 172.20.0.10
options ndots:5
➜ kex utils -- cat /etc/resolv.conf
search default.svc.cluster.local svc.cluster.local cluster.local ec2.internal
nameserver 172.20.0.10
options ndots:5
epod de utilitáriospode consultar o nome do serviçoEstrela da Mortemasvagem xwingnão pode. Somente pelo FQDN do serviço:
➜ kex utils -- nslookup deathstar
Server: 172.20.0.10
Address: 172.20.0.10#53
Name: deathstar.default.svc.cluster.local
Address: 172.20.41.112
➜ kex xwing -- nslookup deathstar
nslookup: can't resolve '(null)': Name does not resolve
➜ kex xwing -- nslookup deathstar.default.svc.cluster.local
nslookup: can't resolve '(null)': Name does not resolve
nslookup: can't resolve 'deathstar': Name does not resolve
command terminated with exit code 1
Name: deathstar.default.svc.cluster.local
Address 1: 172.20.41.112 deathstar.default.svc.cluster.loca
ambos os pods estão sendo executados no mesmo nó eks.
Depois de ativar os logs no coredns, vejo o seguinte:
// kex utils -- nslookup deathstar (success)
[INFO] 10.120.133.213:45918 - 30670 "A IN deathstar.default.svc.cluster.local. udp 53 false 512" NOERROR qr,aa,rd 104 0.000298996s
[INFO] 10.120.133.213:45293 - 18650 "AAAA IN deathstar.default.svc.cluster.local. udp 53 false 512" NOERROR qr,aa,rd 146 0.000405998s
// kex xwing -- nslookup deathstar (failure)
[INFO] 10.120.134.84:32840 - 45185 "AAAA IN deathstar. udp 27 false 512" NXDOMAIN qr,rd,ra 102 0.003295317s
[INFO] 10.120.134.84:32840 - 44875 "A IN deathstar. udp 27 false 512" NXDOMAIN qr,rd,ra 102 0.003334905s