[OS-BUILD PATCH] redhat: spec: trigger dracut when modules are installed separately

[Jan Stancek (via Email Bridge)]

From: Jan Stancek <jstancek(a)redhat.com&gt;

redhat: spec: trigger dracut when modules are installed separately

In most scenarios, users install -core and -modules subpackages
at the same time (as part of same transaction). But it is also
possible to install -core RPM and then -modules RPM separately.
We allow this because some environments don't need modules.

Installing RPMs separately can cause issues. Since we trigger
initramdisk rebuild (in %posttrans script) only for -core package,
some modules may end up missing from init ramdisk.

Introduce state file to determine whether or not -modules subpackage
should trigger dracut to rebuild ramdisk. If both -core and -modules
RPMs are installed in same transaction, there's no extra action.
If -modules RPM is installed separately, trigger dracut in %posttrans
to re-generate init ramdisk.

Signed-off-by: Jan Stancek <jstancek(a)redhat.com&gt;

diff --git a/redhat/kernel.spec.template b/redhat/kernel.spec.template
index blahblah..blahblah 100755
--- a/redhat/kernel.spec.template
+++ b/redhat/kernel.spec.template
@@ -2684,9 +2684,20 @@ fi\
 %define kernel_modules_post() \
 %{expand:%%post %{?1:%{1}-}modules}\
 /sbin/depmod -a %{KVERREL}%{?1:+%{1}}\
+if [ ! -f %{_localstatedir}/lib/rpm-state/kernel/installing_core ]; then\
+	mkdir -p %{_localstatedir}/lib/rpm-state/kernel\
+	touch %{_localstatedir}/lib/rpm-state/kernel/need_to_run_dracut\
+fi\
 %{nil}\
 %{expand:%%postun %{?1:%{1}-}modules}\
 /sbin/depmod -a %{KVERREL}%{?1:+%{1}}\
+%{nil}\
+%{expand:%%posttrans %{?1:%{1}-}modules}\
+if [ -f %{_localstatedir}/lib/rpm-state/kernel/need_to_run_dracut ]; then\
+	echo "Running: dracut -f --kver %{KVERREL}%{?1:+%{1}}"\
+	rm -f %{_localstatedir}/lib/rpm-state/kernel/need_to_run_dracut\
+	dracut -f --kver "%{KVERREL}%{?1:+%{1}}" || exit $?\
+fi\
 %{nil}
 
 # This macro defines a %%posttrans script for a kernel package.
@@ -2701,6 +2712,7 @@ then\
     %{_sbindir}/weak-modules --add-kernel %{KVERREL}%{?1:+%{1}} || exit $?\
 fi\
 %endif\
+rm -f touch %{_localstatedir}/lib/rpm-state/kernel/installing_core\
 /bin/kernel-install add %{KVERREL}%{?1:+%{1}} /lib/modules/%{KVERREL}%{?1:+%{1}}/vmlinuz
|| exit $?\
 %{nil}
 
@@ -2721,6 +2733,8 @@ if [ `uname -i` == "x86_64" -o `uname -i` ==
"i386" ] &&\
    [ -f /etc/sysconfig/kernel ]; then\
   /bin/sed -r -i -e
's/^DEFAULTKERNEL=%{-r*}$/DEFAULTKERNEL=kernel%{?-v:-%{-v*}}/'
/etc/sysconfig/kernel || exit $?\
 fi}\
+mkdir -p %{_localstatedir}/lib/rpm-state/kernel\
+touch %{_localstatedir}/lib/rpm-state/kernel/installing_core\
 %{nil}
 
 #

--
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1644

[Frantisek Hrbata (via Email Bridge)]

From: Frantisek Hrbata on gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1644#note_8715...

Wouldn't it be possible just to use triggerin instead of posttrans here?
```
%{expand:%%triggerin %{?1:%{1}-}core, %{?1:%{1}-}modules}
```
It would run the full kernel-install instead of just the dracut, but maybe
it's not a problem. I haven't tested this at all, so I may be completely off
here.

[Jan Stancek (via Email Bridge)]

From: Jan Stancek on gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1644#note_8716...

Reason for posttrans originates in RHBZ 528063 - to generate initrd only when
all packages (like some optional firmware) are present.

I'm not that familiar with triggerin, so your suggestion raises some
questions.
- What would happen if user installs only kernel-core RPM (without kernel-
modules and kernel meta package)? Would the trigger still run?
- How many times would kernel-install run if you install kernel, kernel-core
and kernel-modules (in single transaction)? Here I assume "1", because kernel
meta package is installed as last one (it has Requires on core and modules)
- How many times would kernel-install run if you install kernel, but already
had 3 older kernels installed? Would trigger run for each kernel?

[Frantisek Hrbata (via Email Bridge)]

From: Frantisek Hrbata on gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1644#note_8718...

>  What would happen if user installs only kernel-core RPM (without
> kernel- 
modules and kernel meta package)? Would the trigger still run?

I would expect that. The docs[1] says:  If multiple items are given (comma
separated), the trigger is run when *any* of those conditions becomes true
(the , can be read as "or").

>  How many times would kernel-install run if you install kernel,
> kernel-core 
and kernel-modules (in single transaction)? Here I assume "1",
because kernel
meta package is installed as last one (it has Requires on core and modules)

Yeah, this might be a problem if you install kernel-core and kernel-modules.
That would probably fire the trigger twice.

>  How many times would kernel-install run if you install kernel, but
> already 
had 3 older kernels installed? Would trigger run for each kernel?

I guess this would have to be hardened by specifying the kernel version in the
trigger. The docs says it supports Requires syntax.

Anyways this was just an idea if the trigger can be used for situation like
this. I've never played with it, so this for sure would have to be properly
verified and tested. But based on your second question it probably will not
work without other tweaks.

Feel free to resolve this, I don't have permissions to do so :smile:

[1] http://ftp.rpm.org/api/4.4.2.2/triggers.html

[Frantisek Hrbata (via Email Bridge)]

From: Frantisek Hrbata on gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1644#note_8719...

FWIW LGM :smile:

[Herton R. Krzesinski (via Email Bridge)]

From: Herton R. Krzesinski on gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1644#note_8723...

Need to remove "touch" from this line.

[Herton R. Krzesinski (via Email Bridge)]

From: Herton R. Krzesinski on gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1644#note_8723...

The logic looks ok however I wonder what happens if you install more than one
kernel flavour in the same transaction. May be use the filename with eg.
%{KVERREL}%{?1:+%{1}} appended, for example
installing_core-%{KVERREL}%{?1:+%{1}}. The same for the need_to_run_dracut,
append something to not make it equal between variants.