NoneNetworkManager is presumably flaky wrt hostname

[apostasie]

Description

https://github.com/containerd/nerdctl/actions/runs/13644906693/job/38141881547?pr=3965#step:11:452

=== RUN   TestNoneNetworkHostName
=== PAUSE TestNoneNetworkHostName
=== CONT  TestNoneNetworkHostName
    container_run_network_linux_test.go:944: 
    container_run_network_linux_test.go:944: ======================== Pre-test cleanup ========================
    command.go:113: /usr/local/bin/nerdctl --namespace=nerdctl-test rm -f testnonenetworkhostname-e70856d3
    container_run_network_linux_test.go:944: 
    container_run_network_linux_test.go:944: ======================== Test setup ========================
    command.go:113: /usr/local/bin/nerdctl --namespace=nerdctl-test run -d --name testnonenetworkhostname-e70856d3 --network none ghcr.io/stargz-containers/nginx:1.19-alpine-org
    container_run_network_linux_test.go:944: 
    container_run_network_linux_test.go:944: ======================== Test Run ========================
    command.go:113: /usr/local/bin/nerdctl --namespace=nerdctl-test exec testnonenetworkhostname-e70856d3 cat /etc/hostname
    command.go:113: assertion failed: 
        --- compare
        +++ stdout
        @@ -1,2 +1 @@
        -0ba62cd1c8fe
         
        : 
        Command:  /usr/local/bin/nerdctl --namespace=nerdctl-test exec testnonenetworkhostname-e70856d3 cat /etc/hostname
        ExitCode: 0
        Stdout:   
        Stderr:   
        Env:
        HOSTNAME=3a911ce1281e
        container=docker
        HOME=/root
        LANG=C.UTF-8
        INVOCATION_ID=6eadd4f97625[456](https://github.com/containerd/nerdctl/actions/runs/13644906693/job/38141881547?pr=3965#step:11:457)0a6a1ac30bc97d4aa
        TERM=xterm
        SHLVL=3
        CGO_ENABLED=0
        _=/usr/local/bin/gotestsum
        PATH=/usr/local/go/bin:/usr/local/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
        ***
        DOCKER_CONFIG=/tmp/TestNoneNetworkHostName1438939296/001
        NERDCTL_TOML=/tmp/TestNoneNetworkHostName1438939296/001/nerdctl.toml
    case.go:173: 
    case.go:174: ======================== Post-test cleanup ========================
    command.go:113: /usr/local/bin/nerdctl --namespace=nerdctl-test rm -f testnonenetworkhostname-e70856d3
--- FAIL: TestNoneNetworkHostName (0.64s)

Tagging @Shubhranshu153

Steps to reproduce the issue

Describe the results you received and expected

na

What version of nerdctl are you using?

main

Are you using a variant of nerdctl? (e.g., Rancher Desktop)

None

Host information

No response

[apostasie]

@AkihiroSuda I do not think this is a CI/test issue at this point.
This seems like a code issue, possibly something racy in network setup with oci-hooks that shows on EL8 because they are much slower.

[Shubhranshu153]

@apostasie
the test is running the container in detached mode is that impacting the test somehow?

[apostasie]

@apostasie the test is running the container in detached mode is that impacting the test somehow?

Maybe? Actually, I just do not know. Would have to look into whether -d exits earlier somehow.

This is clearly a timing issue.

[apostasie]

My money is on ocihooks.

[apostasie]

Other similar issues are showing up on EL8 (because they are so slow):

https://github.com/containerd/nerdctl/actions/runs/13664285641/job/38202209142?pr=3982#step:11:470

This one is about TestHostNetworkDnsConfigs.

That would confirm my suspicion that there is a timing issue with ocihook doing something after the container starts (and that would be for all CNI network managers, not just None).