cloud-init strips ending newline from "/var/lib/cloud/data/previous-hostname"

[ubuntu-server-builder]

This bug was originally filed in Launchpad as LP: #2015043

Launchpad details

affected_projects = []
assignee = None
assignee_name = None
date_closed = None
date_created = 2023-04-03T07:01:08.776906+00:00
date_fix_committed = 2023-04-05T22:05:44.836015+00:00
date_fix_released = None
id = 2015043
importance = undecided
is_complete = False
lp_url = https://bugs.launchpad.net/cloud-init/+bug/2015043
milestone = None
owner = anisinha
owner_name = Anirban Sinha
private = False
status = fix_committed
submitter = anisinha
submitter_name = Anirban Sinha
tags = []
duplicates = []

Launchpad user Anirban Sinha(anisinha) wrote on 2023-04-03T07:01:08.776906+00:00

Steps to Reproduce:

1. enable cloud-init for rhel8

Actual results:
[root@mj-rhel87 ~]# cat /etc/hostname
mj-rhel87
[root@mj-rhel87 ~]# cat /var/lib/cloud/data/previous-hostname
mj-rhel87[root@mj-rhel87 ~]#

2023-03-28 14:47:45,733 - util.py[DEBUG]: Reading from /var/lib/cloud/data/previous-hostname (quiet=False)
2023-03-28 14:47:45,734 - util.py[DEBUG]: Read 9 bytes from /var/lib/cloud/data/previous-hostname
2023-03-28 14:47:45,734 - subp.py[DEBUG]: Running command ['hostname'] with allowed return codes [0] (shell=False, capture=True)
2023-03-28 14:47:45,738 - init.py[INFO]: /var/lib/cloud/data/previous-hostname differs from /etc/hostname, assuming user maintained hostname.

Expected results:
file /var/lib/cloud/data/previous-hostname will be terminated with new line as well

The issue is seen on RHEl 7, RHEL 8 and RHEL 9.

Ubuntu doesn't have this problem.

ubuntu@xiachen-test-ubuntu:$ cat /etc/hostname
xiachen-test-ubuntu
ubuntu@xiachen-test-ubuntu:$ cat /var/lib/cloud/data/previous-hostname
xiachen-test-ubuntu
ubuntu@xiachen-test-ubuntu:~$

[ubuntu-server-builder]

Launchpad user Anirban Sinha(anisinha) wrote on 2023-04-03T10:45:27.893162+00:00

Posted a PR: #2108

[ubuntu-server-builder]

Launchpad user Chad Smith(chad.smith) wrote on 2023-04-05T22:05:40.924299+00:00

Thanks Anirban for submitting the PR and Aciba for review/landing here. Marking Fix committed.

[ubuntu-server-builder]

Launchpad user Chad Smith(chad.smith) wrote on 2023-04-05T22:06:00.772853+00:00

Expect this fix released in cloud-init version 23.2