File /etc/localtime missing

[afbjorklund]

Some runtimes expect /etc/localtime to be present...

Maybe it can be created, to match the output of date ?

Something similar to this workaround:

echo UTC | sudo tee /etc/localtime

[jandubois]

Some runtimes expect /etc/localtime to be present...

Did you mean /etc/timezone? The content for /etc/localtime for UTC is normally

TZif2UTCTZif2UTC
UTC0

Regular setup:

lima-alpine:~# apk add tzdata
(1/1) Installing tzdata (2022c-r0)
Executing busybox-1.35.0-r17.trigger
OK: 49 MiB in 81 packages
lima-alpine:~# setup-timezone -z UTC
lima-alpine:~# ls -l /etc/localtime
lrwxrwxrwx    1 root     root            17 Oct 17 01:44 /etc/localtime -> /etc/zoneinfo/UTC
lima-alpine:~# cat /etc/localtime
TZif2UTCTZif2UTC
UTC0

But which command needs this; the default for date is UTC anyways, so creating the file with default content makes no difference.

[jandubois]

I just realized that zoneinfo files are binary files, so we would actually need to copy it from the tzdata package:

lima-alpine:~# hexdump -C /etc/localtime
00000000  54 5a 69 66 32 00 00 00  00 00 00 00 00 00 00 00  |TZif2...........|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000020  00 00 00 00 00 00 00 01  00 00 00 04 00 00 00 00  |................|
00000030  00 00 55 54 43 00 54 5a  69 66 32 00 00 00 00 00  |..UTC.TZif2.....|
00000040  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000050  00 00 00 00 00 00 00 00  00 00 00 00 00 01 00 00  |................|
00000060  00 04 00 00 00 00 00 00  55 54 43 00 0a 55 54 43  |........UTC..UTC|
00000070  30 0a                                             |0.|
00000072

[afbjorklund]

Did you mean /etc/timezone? The content for /etc/localtime for UTC is normally

Good catch! I will make sure to adjust the workaround then.... (it was for apptainer)

https://github.com/apptainer/apptainer/blob/v1.1.2/pkg/util/apptainerconf/config.go#L107

In the Fedora VM, it is a symlink: /etc/localtime -> ../usr/share/zoneinfo/Etc/UTC
There is no /etc/timezone, only a /etc/adjtime. zoneinfo was from tzdata-2022a-1.fc36

Your approach with adding tzdata package etc to alpine-lima, seems like the best one.
The symlink is resolved automatically, so the end result is a 114-byte binary /etc/localtime.

lima-alpine-apptainer:~$ apptainer run docker://busybox
INFO:    Using cached SIF image
INFO:    fuse2fs not found, will not be able to mount EXT3 filesystems
Apptainer> ls -l /etc/localtime 
-rw-r--r--    1 nobody   nobody         114 Oct 17 08:24 /etc/localtime
Apptainer> exit
lima-alpine-apptainer:~$ ls -l /etc/localtime 
lrwxrwxrwx    1 root     root            17 Oct 17 08:24 /etc/localtime -> /etc/zoneinfo/UTC

[jandubois]

Your approach with adding tzdata package etc to alpine-lima, seems like the best one.
The symlink is resolved automatically, so the end result is a 114-byte binary /etc/localtime.

I would not install all of tzdata into the ISO; I would just copy the single UTC file over after including it on the mkimage.

But first I wanted to make sure we are talking about the right thing; and I want a comment explaining why we are doing this.

[afbjorklund]

You don't have to keep tzdata installed, the generated /etc/localtime and /etc/zoneinfo would be fine.

Here is what alpine-conf is actually doing:

+ rm -r //etc/zoneinfo
+ mkdir -p /etc/zoneinfo/
+ cp //usr/share/zoneinfo/UTC /etc/zoneinfo//
+ zonepath=/etc/zoneinfo/UTC
+ rm -f /etc/localtime
+ ln -s /etc/zoneinfo/UTC /etc/localtime

/bin/sh -x /sbin/setup-timezone -z UTC

[jandubois]

I would not install all of tzdata into the ISO;

I'm not sure why I wrote this, but tools are supposed to treat a missing zoneinfo database the same as if it was configured for UTC. So there wouldn't be a good reason to just copy the UTC data (unless we are dealing with a broken tool).

The whole of tzdata is 3MB, so I think we can just include it completely. Most people don't seem to care about image size anymore (within reason).