Note to self.
umount.target
A special target unit that unmounts all mount and automount points
on system shutdown.
Mounts that shall be unmounted on system shutdown shall add
Conflicts dependencies to this unit for their mount unit, which is implicitly
done
when DefaultDependencies=yes is set (the default).
Given that /media/root-ro is a pre-requisite for /, imho it should be
declared with DefaultDependencies=no.
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1788188
Title:
transient systemd ordering cycle in boot with overlayroot
Status in systemd package in Ubuntu:
Confirmed
Bug description:
open-iscsi test utilizes overlayroot to boot a cloud-image with root
filesystem on a read-only iscsi server.
The /etc/fstab file in the image looks like this:
LABEL=cloudimg-rootfs / ext4 defaults 0 0
#LABEL=UEFI /boot/efi vfat defaults 0 0
when init takes over from the initramfs, we have
/proc/cmdline:
nomodeset iscsi_initiator=maas-enlist
iscsi_target_name=tgt-boot-test-2abbnj iscsi_target_ip=10.0.12.2
iscsi_target_port=3260 iscsi_initiator=maas-enlist
ip=::::maas-enlist:BOOTIF ro net.ifnames=0 BOOTIF_DEFAULT=eth0
root=/dev/disk/by-path/ip-10.0.12.2:3260-iscsi-tgt-boot-test-2abbnj-lun-1-part1
overlayroot=tmpfs console=ttyS0
ds=nocloud-net;seedfrom=http://10.0.12.2:32600/ init=/bin/bash
/etc/fstab:
# cat /etc/fstab
#
# This fstab is in an overlay. The real one can be found at
# /media/root-ro/etc/fstab
# The original entry for '/' and other mounts have been updated to be
placed
# under /media/root-ro.
# To permanently modify this (or any other file), you should change-root
into
# a writable view of the underlying filesystem using:
# sudo overlayroot-chroot
#
#LABEL=cloudimg-rootfs /media/root-ro/ ext4 ro,defaults,noauto 0 0
/media/root-ro/ / overlay
lowerdir=/media/root-ro/,upperdir=/media/root-rw/over0
#LABEL=UEFI /boot/efi vfat defaults 0 0
/root/root-ro/etc/fstab:
LABEL=cloudimg-rootfs / ext4 defaults 0 0
#LABEL=UEFI /boot/efi vfat defaults 0 0
/proc/mounts:
sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
udev /dev devtmpfs
rw,nosuid,relatime,size=233748k,nr_inodes=58437,mode=755 0 0
devpts /dev/pts devpts
rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
tmpfs /run tmpfs rw,nosuid,noexec,relatime,size=49288k,mode=755 0 0
/dev/disk/by-path/ip-10.0.12.2:3260-iscsi-tgt-boot-test-2abbnj-lun-1-part1
/media/root-ro ext4 ro,relatime 0 0
tmpfs-root /media/root-rw tmpfs rw,relatime 0 0
overlayroot / overlay
ro,relatime,lowerdir=/media/root-ro,upperdir=/media/root-rw/overlay,workdir=/media/root-rw/overlay-workdir/_
0 0
/proc/1/mountinfo:
21 28 0:20 / /sys rw,nosuid,nodev,noexec,relatime - sysfs sysfs rw
22 28 0:4 / /proc rw,nosuid,nodev,noexec,relatime - proc proc rw
23 28 0:6 / /dev rw,nosuid,relatime - devtmpfs udev
rw,size=233748k,nr_inodes=58437,mode=755
24 23 0:21 / /dev/pts rw,nosuid,noexec,relatime - devpts devpts
rw,gid=5,mode=620,ptmxmode=000
25 28 0:22 / /run rw,nosuid,noexec,relatime - tmpfs tmpfs
rw,size=49288k,mode=755
26 28 8:1 / /media/root-ro ro,relatime - ext4
/dev/disk/by-path/ip-10.0.12.2:3260-iscsi-tgt-boot-test-2abbnj-lun-1-part1 ro
27 28 0:23 / /media/root-rw rw,relatime - tmpfs tmpfs-root rw
28 0 0:24 / / ro,relatime - overlay overlayroot
ro,lowerdir=/media/root-ro,upperdir=/media/root-rw/overlay,workdir=/media/root-rw/overlay-workdir/_
overlayroot's scripts/init-bottom/overlayroot script [1] inherits a
read-only mount of block device on mount point '$ROOTMNT'
(ROOTMNT=/root). In order to set up the overlayroot, it does the
following:
mkdir /media/root-ro /media/root-rw # in the initramfs
mount -t tmpfs tmpfs-root /media/root-rw
mkdir /media/root-rw/overlay-workdir/_
mount --move $ROOTMNT /media/root-ro
mount -t overlay -o
lowerdir=/media/root-ro,upperdir=/media/root-rw/overlay,workdir=/media/root-rw/overlay-workdir/_
overlayroot /root
mkdir $ROOTMNT/media/root-ro
mkdir $ROOTMNT/media/root-rw
mount --move /media/root-ro "${ROOTMNT}/media/root-ro"
mount --move /media/root-rw "${ROOTMNT}/media/root-rw"
# then, if 'ro' on the command line, it mounts /root read-only.
mount -o remount,ro $ROOTMNT
The script then exits, as ROOTMNT is now set up with a read-only mount
of the overlayroot. All the mounts it has done have been moved
under ROOTMNT.
On failure systemd reports:
[ 104.098833] systemd[1]: media-root\x2dro.mount: Found ordering cycle on
-.mount/start
[ 104.109897] systemd[1]: media-root\x2dro.mount: Found dependency on
media-root\x2dro.mount/start
[ 104.121386] systemd[1]: media-root\x2dro.mount: Unable to break cycle
starting with media-root\x2dro.mount/start
[ 104.137591] systemd[1]: Requested transaction contains an unfixable
cyclic ordering dependency: Resource deadlock avoided
On successful boot, we can login and see:
$ find /run/systemd/ -name "*.mount" | xargs ls -l
-rw-r--r-- 1 root root 322 Aug 21 13:55 /run/systemd/generator/-.mount
lrwxrwxrwx 1 root root 10 Aug 21 13:55
/run/systemd/generator/local-fs.target.requires/-.mount -> ../-.mount
lrwxrwxrwx 1 root root 32 Aug 21 13:55
/run/systemd/units/invocation:dev-hugepages.mount ->
b847fc2d06b54b1ab86a6f526d149522
lrwxrwxrwx 1 root root 32 Aug 21 13:55
/run/systemd/units/invocation:dev-mqueue.mount ->
f991d3bfe35d4e2bb9aa86677ff31d70
lrwxrwxrwx 1 root root 32 Aug 21 13:55
/run/systemd/units/invocation:sys-fs-fuse-connections.mount ->
a561df591a28437f990f94269fa08be9
lrwxrwxrwx 1 root root 32 Aug 21 13:55
/run/systemd/units/invocation:sys-kernel-config.mount ->
141e9bbaca9041e48458749e29bc58fb
lrwxrwxrwx 1 root root 32 Aug 21 13:55
/run/systemd/units/invocation:sys-kernel-debug.mount ->
a406163f265c4b02b37e6f92ddbfc029
$ for f in $(find /run/systemd/ -name '*.mount' -type f); do echo == $f ==;
cat $f; done
== /run/systemd/generator/-.mount ==
# Automatically generated by systemd-fstab-generator
[Unit]
SourcePath=/etc/fstab
Documentation=man:fstab(5) man:systemd-fstab-generator(8)
Before=local-fs.target
[Mount]
Where=/
What=/media/root-ro/
Type=overlay
Options=lowerdir=/media/root-ro/,upperdir=/media/root-rw/overlay/,workdir=/media/root-rw/overlay-workdir/_
--
[1]
https://git.launchpad.net/cloud-initramfs-tools/tree/overlayroot/scripts/init-bottom/overlayroot
Related bugs:
* bug 1723183: [overlayroot] transient systemd ordering issue when using
overlayroot
ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: systemd 237-3ubuntu10
ProcVersionSignature: Ubuntu 4.17.0-6.7-generic 4.17.9
Uname: Linux 4.17.0-6-generic x86_64
ApportVersion: 2.20.10-0ubuntu7
Architecture: amd64
Date: Tue Aug 21 14:06:24 2018
Lsusb: Error: command ['lsusb'] failed with exit code 1:
MachineType: QEMU Standard PC (i440FX + PIIX, 1996)
ProcEnviron:
TERM=vt220
PATH=(custom, no user)
LANG=C.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: nomodeset iscsi_initiator=maas-enlist
iscsi_target_name=tgt-boot-test-2abbnj iscsi_target_ip=10.0.12.2
iscsi_target_port=3260 iscsi_initiator=maas-enlist ip=::::maas-enlist:BOOTIF ro
net.ifnames=0 BOOTIF_DEFAULT=eth0
root=/dev/disk/by-path/ip-10.0.12.2:3260-iscsi-tgt-boot-test-2abbnj-lun-1-part1
overlayroot=tmpfs console=ttyS0 ds=nocloud-net;seedfrom=http://10.0.12.2:32600/
init=/bin/bash
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/01/2014
dmi.bios.vendor: SeaBIOS
dmi.bios.version: 1.11.1-1
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-i440fx-cosmic
dmi.modalias:
dmi:bvnSeaBIOS:bvr1.11.1-1:bd04/01/2014:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-cosmic:cvnQEMU:ct1:cvrpc-i440fx-cosmic:
dmi.product.name: Standard PC (i440FX + PIIX, 1996)
dmi.product.version: pc-i440fx-cosmic
dmi.sys.vendor: QEMU
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1788188/+subscriptions
--
Mailing list: https://launchpad.net/~touch-packages
Post to : touch-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~touch-packages
More help : https://help.launchpad.net/ListHelp
