[Bug]: DataSourceVMware silently ignores network config when specified interface does not exist

[pretamane]

Bug Report: DataSourceVMware silently ignores network config when specified interface does not exist

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Summary

When DataSourceVMware successfully reads network configuration from guestinfo.metadata, but the specified network interface does not exist on the guest OS, cloud-init silently ignores the entire network configuration block without emitting any warning, error, or log entry. The VM boots with no IP address, and there is no indication in any log file as to why.

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Environment

Component	Version / Value
cloud-init version	25.3-0ubuntu1~22.04.1
OS	Ubuntu 22.04 LTS (Jammy)
Image	Ubuntu 22.04 Jammy Cloud Image OVA
Hypervisor	VMware ESXi 6.0 (standalone, no vCenter)
VMware Hardware Version	v10 (ESXi 5.5 and later)
DataSource detected	DataSourceVMware [seed=guestinfo]

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Steps to Reproduce

1. Deploy Ubuntu 22.04 Jammy Cloud Image OVA to VMware ESXi via ovftool
2. Configure guestinfo.metadata with a network config specifying interface ens160:

   network:
     version: 2
     ethernets:
       ens160:        # <-- assumed interface name for VMware (HW v11)
         dhcp4: false
         addresses: [192.168.57.99/24]
         gateway4: 192.168.57.1

3. Power on the VM

Observed: VM boots, hostname set correctly, but no IP assigned. Interface ens32 stays DOWN. Zero log output about the failure.

Expected: A WARNING in /var/log/cloud-init.log that interface ens160 was not found.

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Forensic Evidence

DataSource was detected and read successfully

detail: DataSourceVMware [seed=guestinfo]
errors: []

{ "v1": { "datasource": "DataSourceVMware [seed=guestinfo]", "errors": [] } }

ds-identify.log: Found single datasource: VMware

Verdict: Datasource detection worked perfectly.

No network-disabling files present

/etc/cloud/cloud.cfg.d/ contained only 05_logging.cfg and 90_dpkg.cfg.
No subiquity-disable-cloudinit-networking.cfg. The cloud image OVA was clean.
This rules out the known Subiquity installer artifact as a cause.

/var/log/cloud-init.log — Network section produces ZERO output

grep -i "network|datasource|vmware|guestinfo|disabled|skip" \
  /var/log/cloud-init.log | tail -40
# Output: (completely empty)

This is the critical finding. cloud-init read the datasource, processed it, referenced ens160 which does not exist — and produced no log output whatsoever.

Actual vs assumed interface name

2: ens32: <BROADCAST,MULTICAST> state DOWN   # actual name on HW v10

ens160 is the correct name for VMware HW v11+. On HW v10 (ESXi 5.5/6.0), the interface is named ens32. cloud-init emits no warning about this mismatch.

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Root Cause

When cloud-init processes network: version: 2 from a datasource and the specified interface name(s) do not match any physical interface, the network module completes silently:

• status: done
• errors: []
• No WARNING in /var/log/cloud-init.log
• No entry in result.json

This makes diagnosis impossible without deep external investigation.

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Impact

Any user deploying Ubuntu 22.04 Cloud OVA to VMware ESXi HW v10 who specifies ens160 will experience a completely silent networking failure. Particularly severe in IaC environments (e.g., Terraform) where operators cannot access the VM console.

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VMware Interface Name Reference (Missing from cloud-init docs)

VMware HW Version	ESXi Version	NIC Type	Interface Name
v10	ESXi 5.5 and later	e1000	ens32
v11	ESXi 6.0 and later	vmxnet3	ens160
v13+	ESXi 6.5 and later	vmxnet3	ens192

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Proposed Fix

When the network config specifies an interface that does not exist, emit:

WARNING: Network config specified interface 'ens160' but it was not found.
Available interfaces: ['lo', 'ens32'].
Network configuration was NOT applied.

And set status: warning in result.json rather than status: done.

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Confirmed Workaround

Use match: with a wildcard pattern instead of a hardcoded name:

network:
  version: 2
  ethernets:
    all_nics:
      match:
        name: "e*"
      set-name: eth0
      dhcp4: false
      addresses: [192.168.57.99/24]
      gateway4: 192.168.57.1

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Pre-Filing Checklist

• cloud-init version confirmed: 25.3-0ubuntu1~22.04.1
• DataSource detected correctly: DataSourceVMware [seed=guestinfo]
• NO subiquity-disable-cloudinit-networking.cfg present
• Network log is completely empty (proves silent failure, not blocked failure)
• Workaround confirmed working
• No exact duplicate found for the silent failure aspect
• Reproducible from a clean OVA deployment