Fix: Handle Missing Hostname File in DHCP Configuration

[zhihuiyuze]

Change Summary

After the initial installation of VyOS, the hostname file does not exist, which prevents DHCP configuration. I added a check for the existence of this file to resolve this issue

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

Related PR(s)

Component(s) name

Proposed changes

How to test

Architecture:     x86_64
Boot via:         installed image
System type:      KVM guest

Hardware vendor:  QEMU
Hardware model:   Standard PC (i440FX + PIIX, 1996)
Hardware S/N:     
Hardware UUID:    6d392efb-9581-4438-925a-67f195d695ca

Traceback (most recent call last):
  File "/usr/libexec/vyos/conf_mode/interfaces_ethernet.py", line 433, in <module>
    apply(c)
  File "/usr/libexec/vyos/conf_mode/interfaces_ethernet.py", line 410, in apply
    e.update(ethernet)
  File "/usr/lib/python3/dist-packages/vyos/ifconfig/ethernet.py", line 454, in update
    super().update(config)
  File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 1603, in update
    self.add_addr(addr)
  File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 1194, in add_addr
    self.set_dhcp(True)
  File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 1361, in set_dhcp
    with open('/etc/hostname', 'r') as f:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '/etc/hostname'

noteworthy:

After adding the check, the DHCP configuration function no longer reports errors.

Smoketest result

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[c-po]

Thanks for the fix!

Please see https://github.com/vyos/vyos-1x/blob/current/CONTRIBUTING.md as every fix requires a task ID which is used to generate release notes.

[c-po]

This PR lacks some more context. Which version was used while the bug occured? I've tested

• 1.4.0-epa2 template in EVE-NG
• 1.4.0-epa3 live cd
• 1.4.0-epa3 fresh install and all of them come with a /etc/hostname file.

A slight chance exists that there is a race condition during boot as host-name CLI know is not called with any priority https://github.com/vyos/vyos-1x/blob/c15ee875a6ed6d2f053ad0dd6d576b93a6ea858f/interface-definitions/system_host-name.xml.in

This will be handled via https://vyos.dev/T6421 and thus will solve the potential race condition leading to the root cause for this PR.

Thanks you again for the contribution.

I referenced your initial idea here: cf07a55

[zhihuiyuze]

I installed the system using vyos-1.5-rolling-202405270020-amd64, and I believe the rolling code corresponds to the current branch on GitHub

Please see https://github.com/vyos/vyos-1x/blob/current/CONTRIBUTING.md as every fix requires a task ID which is used to generate release notes.

Got it. I need to create a task ID first.