feat(nodeadm): add console logging support to nodeadm

[chenwng]

Issue #, if available:

N/A

Description of changes:

This PR adds a global flag --console to enable sending nodeadm logs to the node console. This helps troubleshoot node not joining cluster issues and the access to node is limited. The global flag --console defaults to false to be backward compatible.

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[fletcherw]

Hello! This is an interesting change, but I'm not sure we want to enable this by default. Can you say more about your issues with "This helps troubleshoot node not joining cluster issues and the access to node is limited." Do you have nodes where SSM or SSH access are not possible?

[fletcherw]

After further discussion, I think we're actually good to do this via systemd, that way the log output sent to the console is timestamped and has the systemd unit name like so:

[    7.468759] cloud-init[2247]: Cloud-init v. 22.2.2 running 'modules:config' at Thu, 19 Feb 2026 20:17:38 +0000. Up 7.41 seconds.
[    8.005622] cloud-init[2260]: Cloud-init v. 22.2.2 running 'modules:final' at Thu, 19 Feb 2026 20:17:39 +0000. Up 7.93 seconds.
[    8.065212] cloud-init[2260]: Cloud-init v. 22.2.2 finished at Thu, 19 Feb 2026 20:17:39 +0000. Datasource DataSourceEc2.  Up 8.05 seconds
[    8.181199] nodeadm[2261]: info init/init.go:55 Checking user is root..
[    8.182677] nodeadm[2261]: info init/init.go:65 Loading configuration.. {"configSource": ["imds://user-data", "file:///etc/eks/nodeadm.d/"], "configCache": "/run/eks/nodeadm/config.json"}
[    8.188546] nodeadm[2261]: warn configprovider/chain.go:30 Encountered error in config provider {"error": "no config found in directory"}
[    8.190862] nodeadm[2261]: info init/init.go:75 Setting up nodeadm environment aspect..

No need to modify the nodeadm logger code.

[chenwng]

Thanks for the suggestion. I've updated the PR. Please help review it.

[fletcherw]

gosec failure is a false positive, proceeding to merge.