conduit_proxy doesn't resolve IPv6 name about linkerd2

[valentin2105]

Hi @olix0r,
I don't have follow any docs about that but I wrote a detailed blog post about that,

https://opsnotice.xyz/kubernetes-ipv6-only/

I will continu to try too in my cluster to report any problem ;)

Thanks !

[olix0r]

Thanks for this report! It's important to us that Conduit support things like IPv6 out-of-the-box.

Can you share any pointers/references/docs on how you've set up your kubernetes cluster to use IPv6? I'd like to replicate this environment for integration tests.

[briansmith]

Like @olix0r said, we definitely want to support IPv6-only configurations. I believe there's only one place where we use DNS in Conduit: resolving the hostname of the control plane. Until we find out what the issue is with that, you may be able to work around this by allocating an IPv4 address only to the control plane pods.

#257 was filed as a duplicate of this, which may mean there's more interest in IPv6-only configurations than we expected, so we should consider increasing the priority.

[valentin2105]

Hi,

Sorry for opened two issue, I forgot about the first one lol,

Yeah, conduit seem really a great product and I really looking forward about trying this with my production services in IPv6 cluster and more since you support HTTP1.1 and TCP stuffs.

I can support you on the testing side if you release some test image, I can try them quickly if needed ;)

[wmorgan]

IPv6 support is currently unprioritized, but contributions are welcome! Specific error reports around breakages due to IPv6 also welcome.

[valentin2105]

I gived a new try on v0.4.0 release,

I don't get any error on the Conduit deployment,

But when I deploy my Nginx deployment with conduit-proxy, here is the logs :

INFO conduit_proxy using controller at HostAndPort { host: DnsName(Name(Name("proxy-api.conduit.svc.k8s.my-cluster.tld"))), port: 8086 }
INFO conduit_proxy routing on V4(127.0.0.1:4140)
INFO conduit_proxy proxying on V4(0.0.0.0:4143) to None
INFO conduit_proxy serving Prometheus metrics on V4(0.0.0.0:4191)
INFO conduit_proxy protocol detection disabled for inbound ports {25, 3306}
INFO conduit_proxy protocol detection disabled for outbound ports {25, 3306}
ERR! conduit_proxy::control "controller-client", controller error: Error attempting to establish underlying session layer: DNS resolution failed

If it can help ! 😄

[olix0r]

@valentin2105 thanks for the updated information! i think we're getting closer to being able to fix this. as we improve some of the discovery logic for 0.5, we can take a look trying to determine what has to change in the proxy to accommodate this.

[valentin2105]

@olix0r Thanks for investigating this,
Looking forward seen conduit running at glance on IPv6 ;)

[briansmith]

This is most likely due to limitations of the abstract_ns/ns_dns_tokio crates. In particular, note things like https://github.com/tailhook/abstract-ns/blob/af4fa2abe1aed67c505364cc78aaf2e7dd5fcb10/ns-dns-tokio/src/lib.rs#L72-L81 where AAAA support just wasn't considered yet.

I think we'll have to switch to another crate--probably Trust-DNS--to fix this.

[valentin2105]

@briansmith TrustDNS seem really better and support IPv6.
Pretty strange for a DNS library to support only IPv4..

[grampelberg]

Tracking IPv6 support in #3849.