Bug 2374173

Summary:	[RFE]: allow the Anaconda user to specify whether the system's RTC is in UTC or local time
Product:	[Fedora] Fedora	Reporter:	pg_tips <pg_forums>
Component:	anaconda	Assignee:	anaconda-maint
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	44	CC:	8ru2u4gz, anaconda-maint, doug.hs, kkoukiou, w
Target Milestone:	---	Keywords:	RFE
Target Release:	---
Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description pg_tips 2025-06-21 17:43:59 UTC

Background
==========
Currently Anaconda attempts to guess whether the target system's real-time clock (RTC) should be assumed to be in local time. If there is apparently a pre-existing Windows installation on the target machine, the RTC is assumed to be in local time, else in RTC.

See the function "time_initialize" in timezone.py, which ultimately relies on a set of Windows-detecting heuristics in the "is_valid_stage2_device" method of the base "BootLoader" class.

This can go wrong for a couple of reasons:
1) The heuristics are not 100% reliable in detecting a Windows install. (I've seen different results across two different machines, both of which involved Fedora being installed as a dual-boot with a pre-existing Windows 10 install.)

2) Even if Anaconda were 100% reliable in detecting Windows, the presence of a Windows install does not necessarily entail that the RTC is in local time. Windows can be configured to use an RTC in UTC.

Feature request
===============
Because some users will know for a fact whether or not the RTC is in local time, the installer UI should allow them to specify this and bypass the heuristics.

Reproducible: Sometimes

Steps to Reproduce:
1. Use Anaconda to install Fedora on a disk which has an existing Windows 10 install.
2. Boot into Fedora and execute `timedatectl` to check the setting for "RTC in local TZ"

Actual Results:
On one system, "RTC in local TZ" was "yes"; on the other it was "no".

Expected Results:
The *expected* result according to Anaconda's internal logic should have been "RTC in local TZ"=="yes" in both cases.

The *ideal* result per this feature request would have been for Anaconda to allow me to stipulate that the RTC was in UTC. Then I would have seen "RTC in local TZ"=="no" on both systems. (I had configured Windows to use a UTC RTC on both these machines.)

Comment 1 Mr. Beedell, Roke Julian Lockhart (RJLB) 2025-06-21 19:00:42 UTC

(In reply to pg_tips from comment #0)

This would be useful to me, because I have my Windows installation set to UTC, meaning that if I re-install Linux, I don't want Anaconda to assume RTC.

Comment 2 Fedora Release Engineering 2026-05-06 13:18:53 UTC

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