podman remote bypass system resolver and fails to resolve mDNS hostnames.

[Jean-Daniel]

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind bug

Description

When trying to connect to a ".local" hostname with Podman remote, it tries to resolve the hostname by querying the network DNS instead of using the local resolver and fails to resolve the hostname.

I have a running machine that advertise the podman.local hostname using a mDNS daemon. This host is perfectly reachable from my macOS machine using ssh, ping and any other tool. But when trying to connect it using podman, it fails with

error `Error: failed to create sshClient: Connection to bastion host (ssh://[email protected]:22/run/podman/podman.sock) failed.: dial tcp: lookup podman.local on 10.2.0.1:53: no such host`

10.2.0.1 is the local network DNS server (as declared in the generated /etc/resolv.conf) but by bypassing the local resolver/cache, podman fails to properly resolve the remote hostname.

Steps to reproduce the issue:

1. Start a VM with avahi (to advertise the .local hostname), and podman.

2. On a host that can reach this VM via ssh, configure a podman remote connection using '.local' as server name.

3. Try to connect to it (podman info)

Describe the results you received:

Podman try to use its own DNS resolver machinery and fails to resolve the hostname.

Describe the results you expected:

Podman properly use the system resolver and connect to the remote host.

Output of podman version:

podman version 3.2.1

Have you tested with the latest version of Podman and have you checked the Podman Troubleshooting Guide? (https://github.com/containers/podman/blob/master/troubleshooting.md)

Yes

[jwhonce]

@Jean-Daniel We will have to dig into the cause here. Podman currently delegates this lookup to the Go ssh library. See https://github.com/containers/podman/blob/master/pkg/bindings/connection.go#L263

/cc @baude

[github-actions]

A friendly reminder that this issue had no activity for 30 days.

[rhatdan]

@jwhonce Any thing new on this one?

[github-actions]

A friendly reminder that this issue had no activity for 30 days.

[github-actions]

A friendly reminder that this issue had no activity for 30 days.

[rhatdan]

@Jean-Daniel Are you still seeing this issue?

[rhatdan]

If you ssh into the VM and using podman there, do you see the same problem?

[jwhonce]

@rhatdan I have reproduce the issue on Big Sur and it appears to be related to golang/go#12524 . I want to talk to @ashley-cui about packaging to see if we can tweak the Makefile to use cgo when building via homebrew.

[ashley-cui]

@jwhonce to use cgo in homebrew, it should be as simple as adding ENV["CGO_ENABLED"] = "1" to the homebrew formula. I'm not too too familiar with out makefile, would we have to make changes there too?

[jwhonce]

@ashley-cui Yeah, I'll make a PR with the needed changes to the Makefile. BTW, I used brew reinstall -s podman to rebuild podman on my mac.