ipv6_ready referenced before assignment

[Jerry Cheng]

cloud-init crashes due to reference ipv6_ready before assignment.
cloud-init version: 22.2.2-1.ph3

traceback in cloudinit/sources/DataSourceVMware.py:

[2022-08-15 17:38:14] 2022-08-15 17:38:14,682 - util.py[WARNING]: failed stage init

[2022-08-15 17:38:14] failed run of stage init

[2022-08-15 17:38:14] ------------------------------------------------------------

[2022-08-15 17:38:14] Traceback (most recent call last):

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/cmd/main.py", line 740, in status_wrapper

[2022-08-15 17:38:14] ret = functor(name, args)

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/cmd/main.py", line 429, in main_init

[2022-08-15 17:38:14] init.setup_datasource()

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/stages.py", line 468, in setup_datasource

[2022-08-15 17:38:14] self.datasource.setup(is_new_instance=self.is_new_instance())

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/sources/DataSourceVMware.py", line 340, in setup

[2022-08-15 17:38:14] host_info = wait_on_network(self.metadata)

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/sources/DataSourceVMware.py", line 963, in wait_on_network

[2022-08-15 17:38:14] ipv6_ready,

[2022-08-15 17:38:14] UnboundLocalError: local variable 'ipv6_ready' referenced before assignment

There is an issue in the source code: under certain conditions, ipv6_ready may be referenced in LOG.debug() before assignment if wait_on_ipv6 = false. The same issue may also happen for ipv4_ready if wait_on_ipv4 = false.

host_info = None

    while host_info is None:

        # This loop + sleep results in two logs every second while waiting

        # for either ipv4 or ipv6 up. Do we really need to log each iteration

        # or can we log once and log on successful exit?

        host_info = get_host_info()

        network = host_info.get("network") or {}

        interfaces = network.get("interfaces") or {}

        by_ipv4 = interfaces.get("by-ipv4") or {}

        by_ipv6 = interfaces.get("by-ipv6") or {}

        if wait_on_ipv4:

            ipv4_ready = len(by_ipv4) > 0 if by_ipv4 else False

            if not ipv4_ready:

                host_info = None

        if wait_on_ipv6:

            ipv6_ready = len(by_ipv6) > 0 if by_ipv6 else False

            if not ipv6_ready:

                host_info = None

        if host_info is None:

            LOG.debug(

                "waiting on network: wait4=%s, ready4=%s, wait6=%s, ready6=%s",

                wait_on_ipv4,

                ipv4_ready,

                wait_on_ipv6,

                ipv6_ready,

            )

            time.sleep(1)

[Andrew Kutz (akutz)]

Opened PR to fix the issue -- https://github.com/canonical/cloud-init/pull/1674

[Chad Smith (chad.smith)]

Thanks Andrew for the upstream commit here.
https://github.com/canonical/cloud-init/commit/9f0efc474ea430c75cd0abec3e2da719d4934346

This will be in cloud-init the next cloud-init SRU of 22.3-X which should also make it into Ubuntu Bionic, Focal and Jammy in the next 2 weeks.

I realize this doesn't help Photon OS, but wanted to provide a reference in case this hits Ubuntu consumers too.

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/4011