VMware datasource: guestinfo.local-ipv6 unset when iface has global + link-local IPv6

[hpannem]

Bug report

On Linux, netinfo.netdev_info() records multiple IPv6 addresses per NIC (global + fe80). DataSourceVMware.get_default_ip_addrs() only assigns an IPv6 when len(netdev[iface]["ipv6"]) == 1, so IPv6 becomes None and guestinfo.local-ipv6 is never advertised. IPv4 works because there is typically a single IPv4 global address on the NIC.

Steps to reproduce the problem

sudo python3 -c "from cloudinit.netinfo import netdev_info; n=netdev_info(); print({k: len(v.get('ipv6',[])) for k,v in n.items()})"
sudo python3 -c "import cloudinit.sources.DataSourceVMware as ds; print(ds.get_default_ip_addrs())"

Example: eth0 has ipv6 count 2, get_default_ip_addrs() returns (v4, None).

###Expected (arguable)
Exclude link-local/loopback/unspecified before applying the len == 1 rule.

###Actual
local-ipv6 absent; info-get guestinfo.local-ipv6 → no value.

Environment details

• Cloud-init version: 25.1.3
• Operating System Distribution: VMware Photon OS 5.0
• Cloud provider, platform or installer type: vSphere VM

##References
Same tree: cloudinit/netinfo.py (_netdev_info_iproute_json), cloudinit/sources/DataSourceVMware.py (get_default_ip_addrs, guestinfo_set_value for local-ipv6).

cloud-init logs

[holmanb]

On Linux, netinfo.netdev_info() records multiple IPv6 addresses per NIC (global + fe80).

Can you please describe the issue in terms of a user-facing problem?

[akutz]

I think he is saying if there is a non-link local IP6 addr and a link local one, the link-local one keeps the global one from being advertised?

[hpannem]

Yes. If there are multiple IP address such as link local and global, the code filters the global one saying "multiple IPs are detected on the interface" and hence the global IP is not advertised.

[holmanb]

Please collect logs and attach them to this bug report.