[systemd-devel] experiments with 'minimal build'

[Alison Chaiken]

After reading about the 'minimal build' on the systemd wiki, I decided
to experiment.

0. WIth basically all options turned on, in a Fedora 21 Qemu, systemd
used about 300 MB of memory according to 'sudo memstat -p 1'.

1. With ./configure --disable-gtk-doc --disable-seccomp
--disable-selinux --disable-apparmor --disable-xz --disable-zlib
--disable-pam --disable-acl --disable-smack --disable-gcrypt
--disable-audit --disable-elfutils --disable-libcryptsetup
--disable-qrencode --disable-microhttpd --disable-gnutls
--disable-libcurl --disable-libidn  --disable-quotacheck
--disable-vconsole --disable-logind --disable-machined
--disable-importd --disable-hostnamed --disable-timedated
--disable-localed --disable-polkit --disable-resolved
--disable-networkd --disable-efi --disable-manpages
--disable-hibernate --disable-tests

[achaiken at localhost systemd (master)]$ ./systemd --version
systemd 219
-PAM -AUDIT -SELINUX +IMA -APPARMOR -SMACK +SYSVINIT +UTMP
-LIBCRYPTSETUP -GCRYPT -GNUTLS -ACL -XZ -LZ4 -SECCOMP +BLKID -ELFUTILS
+KMOD -IDN

In this case, 'memstat -p 1' says systemd uses about 119 MB of memory.

2. Reducing even further,

./configure --disable-gtk-doc --disable-seccomp --disable-selinux
--disable-apparmor --disable-xz --disable-zlib --disable-pam
--disable-acl --disable-smack --disable-gcrypt --disable-audit
--disable-elfutils --disable-libcryptsetup --disable-qrencode
--disable-microhttpd --disable-gnutls --disable-libcurl
--disable-libidn  --disable-quotacheck --disable-vconsole
--disable-logind --disable-machined --disable-importd
--disable-hostnamed --disable-timedated --disable-localed
--disable-polkit --disable-resolved --disable-networkd --disable-efi
--disable-manpages --disable-hibernate --disable-tests  --disable-nls
--disable-python-devel --disable-utmp --disable-xkbcommon
--disable-ima --disable-blkid --disable-binfmt --disable-tmpfiles
--disable-sysusers --disable-firstboot --disable-randomseed
--disable-backlight --disable-rfkill --disable-timesyncd
--disable-coredump --disable-myhostname
[achaiken at localhost systemd (master)]$ ./systemd --version
systemd 219
-PAM -AUDIT -SELINUX -IMA -APPARMOR -SMACK +SYSVINIT -UTMP
-LIBCRYPTSETUP -GCRYPT -GNUTLS -ACL -XZ -LZ4 -SECCOMP -BLKID -ELFUTILS
+KMOD -IDN

Now Qemu doesn't boot because "Dependency failed for /boot"
"Dependency failed for /home".   From emergency shell, 'journalctl -p
err' shows 5 udev failures and 8 systemd ones.   /boot and /home are
empty because fedora-home and the UUID-labelled object are absent in
/dev/mapper.   The last successful target is Swap.

Hypothesis: the failure happened because I turned BLKID off.   Does
that sound right?   Does systemd not work without BLKID?   Would it
work with BLKID off it it hadn't previously been on at installation?

Obviously this was a sandbox experiment and nothing valuable was lost,
but nonetheless I'm curious.   I assume that turning off KMOD and
perhaps SYSVINIT isn't safe either?

Thanks for any suggestions,
Alison


-- 
Alison Chaiken                           alison at she-devel.com
650-279-5600
http://{she-devel.com,exerciseforthereader.org}
One consumes a great deal of silence in the course of becoming
educated. -- Matthew B. Crawford