Flaky test: TestRunAddHost

[AkihiroSuda]

=== CONT  TestRunAddHost
    run_linux_test.go:108: assertion failed: error is not nil: host was not added, found 0: # <nerdctl>
        127.0.0.1	localhost localhost.localdomain
        :1		localhost localhost.localdomain
        10.0.0.1        test1 test
        10.4.0.140      07fc66977787 alpine-07fc6
        10.4.0.141      ca0911dbb51c alpine-ca091
        127.0.0.1       localhost localhost.localdomain
        :1              localhost localhost.localdomain
        # </nerdctl>
--- FAIL: TestRunAddHost (0.96s)

[manugupt1]

This seems very specific to the CI.

I can see the failures in #1137

I can't reproduce in either ubuntu (GNOME boxes) / fedora 36 even after 100 runs.

This is the command that I used.

 go test -exec sudo -v ./cmd/nerdctl/... -run TestRunAddHost -count=100^C

[AkihiroSuda]

The test expects nerdctl run --rm --add-host test:10.0.0.1 --add-host test1:10.0.0.1 alpine cat /etc/hosts to generate a file like this

# <nerdctl>
127.0.0.1       localhost localhost.localdomain
:1              localhost localhost.localdomain
10.0.0.1        test
10.0.0.1        test1
10.4.0.9        d7c0252b581c alpine-d7c02
# </nerdctl>

But occasionally the two lines for 10.0.0.1 are merged into 10.0.0.1 test1 test (seems legit, but should not happen occasionally)

[AkihiroSuda]

Looks like the localhost lines are written twice in the failed case, so something seems calling the hosts updater twice