fix(vrouter): preserve configured router hostnames

[GhostofGoes]

Description

tl;dr: remove special handling for router hostnames, set them exactly as defined in topology

Previously Node.RouterName() lowercased router hostnames and replaced . and _ with -. That made the guest hostname differ from the minimega VM name, so exact-match lookups such as cc filter hostname= missed routers. This special handling is no longer necessary with the hostname validation added in #268

Background

Why the rewrite existed, and why it's safe to remove:

• RouterName() was added with the original Vyatta app in f7c9d35 (2020). No commit says why. Its only caller is system host-name in vyatta.tmpl. Minirouter never used it, and the startup app skips routers.
• Vyatta and every VyOS release validate host-name against [A-Za-z0-9][-.A-Za-z0-9]*[A-Za-z0-9] (max 63) and never lowercase it. Uppercase letters and dots are accepted. Only _ is rejected.
• The topology schema has rejected _ and . in hostnames since 65f8e83, so the ./_ rewrite only mattered for configs that skipped validation.
• Firewall nodes are rendered from the same template, and RouterName() never rewrote their hostnames.

Changes

• Remove RouterName() from the v0 and v1 Node types. vyatta.tmpl now uses $node.General.Hostname, like the Linux and Windows startup templates.
• Add a template test that renders both the VyOS script and the Vyatta config.boot with a mixed-case hostname.
• CHANGELOG entry.

Related Issues/PRs

• Closes [BUG] Router hostnames converted to lower #335
• fix(schema): require hostnames of at least 2 characters #429
• fix(topology): better validation of node hostnames #430
• test(utils): replace obsolete router hostname fixture in cc locate tests sceptre-phenix-apps#148

Type of Change

• Bugfix (fix)
• Feature (feat)
• Documentation (docs)
• Refactor (refactor)
• Chore (CI, build, dependencies, etc.) (chore)
• Other (please describe):

Checklist

• This PR conforms to the process detailed in the Contributing Guide.
• I have included no proprietary/sensitive information in my code or the PR.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• I have tested my code (describe below).

Testing

Tested with an experiment with a VyOS router, tweaking the hostname a few times: router, ROUTER1, ROUTER-123.

Additional Notes

A config created with --skip-validation, or stored before 65f8e83, that has _ in a router hostname will now have VyOS reject the host-name line instead of getting - in its place. Renaming the node fixes it.

🤖 Generated with Claude Code

[nblair2]

The question - why are those changes made (vyos, vyatta, minirouter requirements)? If these are requirements they should be added to the schema, validated at configure time.

[GhostofGoes]

@nblair2 RouterName() came in with the original Vyatta app in f7c9d35 (April 2020). No commit explains it, and it only ever fed system host-name in vyatta.tmpl. Minirouter never used it, and the startup app skips routers.

Vyatta and every VyOS release validate host-name against [A-Za-z0-9][-.A-Za-z0-9]*[A-Za-z0-9] (max 63) and never lowercase it. Lowercasing was never a requirement. Underscore is the only rejected character, and the schema pattern from 65f8e83 already rejects _ and . when a config is created. Firewall nodes use the same template and were never rewritten either. I removed RouterName() and render the hostname as written.

That regex also needs at least 2 characters, and Windows DNS host names have the same minimum, so #429 raises the schema's hostname minimum from 1 to 2 (docs: sandialabs/sceptre-phenix-docs#70). sandialabs/sceptre-phenix-apps#148 replaces the apps test fixture that modeled the old rewrite.

One caveat: a config created with --skip-validation that has _ in a router hostname will now have VyOS reject the host-name line instead of getting - in its place.

[cmulk]

makes sense to me, just need to fix the changelog conflict

[GhostofGoes]

@cmulk resolved