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We have a problem where sometimes the lxc-apt-update action fails due to a failing DNS request:

Everytime this happens, we observe that the LXC got an IPv6 address only:

To verify that this is correlated, we added a delay to wait for an IPv4 address to the LXC code:

diff --git a/lava_dispatcher/actions/boot/lxc.py.bak b/lava_dispatcher/actions/boot/lxc.py
index 64bcfc2..a0677d7 100644
--- a/lxc.py.bak
+++ b/lxc.py
@@ -177,7 +177,11 @@ class LxcStartAction(Action):
        while True:
            command_output = self.run_command(lxc_cmd, allow_fail=True)
            if command_output:
+                self.logger.debug("'%s' Wait 30 seconds", lxc_name)
+                time.sleep(30)
+                command_output = self.run_command(lxc_cmd, allow_fail=True)
                break
+            self.logger.debug("'%s' Wait 10 seconds before next poll", lxc_name)
            time.sleep(self.sleep)  # poll every 10 seconds.
        self.logger.info("'%s' IP address is: '%s'", lxc_name, command_output.strip())
        return connection

Afterwards the LXC gets IPv4 and IPv6 addresses:

And the lxc-apt-update action succeeds:

Is this something anybody else has observed? Can we maybe add some kind of flag to ensure that LXC devices get both an IPv4 and IPv6 address?