Ignore ServFail / NxDomain for search list, e.g. in Kubernetes cluster

amphp / dns

Async DNS resolution for PHP based on Amp.

https://amphp.org/dns

MIT License

156 stars 32 forks source link

Ignore ServFail / NxDomain for search list, e.g. in Kubernetes cluster #99

Closed roquie closed 4 years ago

roquie commented 4 years ago

Any requests called with amphp/http-client will use these dns package. Where requests will sent inside kubernetes cluster it fails with following reason:

In Rfc1035StubResolver.php line 193:

  All query attempts failed for {{ADDRESS}}-prod.svc.cluster.l
  ocal: Server returned error code: 3, Server returned error code: 3

In functions.php line 534:

  Multiple errors encountered; use Amp\MultiReasonException::getReasons() to
  retrieve the array of exceptions thrown

Requests from pod to pod inside a same namespace in Kubernetes cluster by service name (kubectl get svc). If using local ip address instead of dns it works. But this workaround is not possible for all cases.

I think this is critical issue because a lot of many users use Kubernetes every day.

PHP: 7.4.5 amphp/amp: v2.4.4 amphp/dns: v1.2.1 amphp/http-client: v4.2.2 OS: Alpine

UV extension installed from pecl.

roquie commented 4 years ago

https://github.com/amphp/dns/issues/41

kelunik commented 4 years ago

I haven't used Kubernetes, yet. How does DNS resolution work there? What's different?

roquie commented 4 years ago

Sorry for long answer. On next week I will be again works with amphp/dns and try to run series of tests in cluster. Before this bug I should fix the issue with amphp/postgres because it blocks my work.

roquie commented 4 years ago

1.2.1 does not work in cluster with global available addresses (tested github.com and api.telegram.org), but 0.9.15 works fine.
0.9.15 also does not work with local domain names in kubernetes cluster
1.1.0 works same as 0.9.15

In all cases gethostbyname returns ip.

UPD: For 1.2.1 version this hack not help me. https://github.com/amphp/dns/issues/82

/etc/resolv.conf

cat /etc/resolv.conf
nameserver 172.17.0.10
search calcifer-dev.svc.cluster.local svc.cluster.local cluster.local
options ndots:5

I'm trying to find some bugs in PR https://github.com/amphp/dns/pull/89 ...

kelunik commented 4 years ago

What's the error message you get for github.com?

roquie commented 4 years ago

kelunik commented 4 years ago

Please retry with https://github.com/amphp/dns/commit/8cf2ccc4fa5a97f15b0b11087b22d2b544e45ab2 / latest dev-master.

roquie commented 4 years ago

Yes, that works in all cases. Thanks! :)

kelunik commented 4 years ago

Thanks for testing! Tagged as v1.2.2.