47 Troubleshooting Edge Networking (NMC) #

NMC is injected on SL Micro EIB images to configure the network of the Edge hosts at boot time via combustion. It is also being executed on the Metal3 workflow as part of the inspection process. Issues can happen when the host is being booted for the first time or on the Metal3 inspection process.

Common Issues #

Host not being able to boot properly the first time: Malformed network definition files can lead to the combustion phase to fail and then the host drops a root shell.
Files are not properly generated: Ensure the network files matches NMState format.
Network interfaces are not correctly configured: Ensure the MAC addresses match the interfaces being used on the host.
Mismatch between interface names: The net.ifnames=1 kernel argument enables Predictable Naming Scheme for Network Interfaces so there is no eth0 anymore but other naming schema such as enp2s0.

Logs #

Combustion logs: As nmc is being used at combustion time, check combustion logs with journalctl -u combustion on the host being provisioned.
NetworkManager logs: On the Metal³ deployment workflow, nmc is part of the IPA execution and it is being executed as a dependency of the NetworkManager service using systemd’s ExecStartPre functionality. Check NetworkManager logs on the IPA host as journalctl -u NetworkManager (see the Troubleshooting Directed-network provisioning (Chapter 49, Troubleshooting Directed-network provisioning) section to understand how to access the host when booted with IPA).

Troubleshooting steps #

Verify the yaml syntax: nmc configuration files are yaml files, check the proper syntax with yamllint or similar tools.

Run nmc manually: As nmc is part of the EIB container, to debug any issues, a local podman command can be used.

Create a temporary folder to store the nmc files.
```
mkdir -p ${HOME}/tmp/foo
```

Save the nmc files on that location.

❯ tree --noreport ${HOME}/tmp/foo
/Users/johndoe/tmp/foo
├── host1.example.com.yaml
└── host2.example.com.yaml

Run the EIB container with nmc as the entrypoint and the generate command to perform the same tasks nmc would do at combustion time:

podman run -it --rm -v ${HOME}/tmp/foo:/tmp/foo:Z --entrypoint=/usr/bin/nmc registry.suse.com/edge/3.3/edge-image-builder:1.2.0 generate --config-dir /tmp/foo --output-dir /tmp/foo/

[2025-06-04T11:58:37Z INFO  nmc::generate_conf] Generating config from "/tmp/foo/host2.example.com.yaml"...
[2025-06-04T11:58:37Z INFO  nmc::generate_conf] Generating config from "/tmp/foo/host1.example.com.yaml"...
[2025-06-04T11:58:37Z INFO  nmc] Successfully generated and stored network config

Observe the logs and files being generated on the temporary folder.