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IDProjectCategoryView StatusLast Update
0015871CentOS-7systemdpublic2019-02-28 10:11
Reporterdmz 
PrioritynormalSeveritymajorReproducibilityalways
Status assignedResolutionopen 
Product Version7.6.1810 
Target VersionFixed in Version 
Summary0015871: Systemd resets all mountpoints to shared propagation on update
DescriptionWe are creating mountpoints on the filesystem with propagation semantics other than shared. On performing a yum update to systemd we found that all of these mounts were reset to shared propagation. I understand that systemd sets all mounts to shared on system startup, but surely it cannot be correct that the whole system is reset on update? This basically killed our server.
Steps To Reproduce1. create a mountpoint with non-shared propagation.
2. perform a yum update to systemd.
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JohnnyHughes

JohnnyHughes

2019-02-26 18:15

administrator   ~0033908

systemd has various '<name>.d/' dirs for definitions .. did you possibly modify a system config file and not use the applicable .d directory for your config changes.
TrevorH

TrevorH

2019-02-26 18:17

manager   ~0033909

Perhaps it might be useful to explain in words of one syllable what on earth "mountpoints on the filesystem with propagation semantics other than shared" actually means?
dmz

dmz

2019-02-28 10:08

reporter   ~0033915

Simple example:

1. Display mount information with propagation, you will find that they are all shared on CentOS7 (or any distribution using systemd, due to systemd performing a mount(NULL, "/", NULL, MS_SHARED|MS_REC, NULL) on startup, replacing the kernel default of private):
$ findmnt -o+PROPAGATION

... (note all shared)

2. Mount a filesystem with different mount semantics:
# mount -t tmpfs -osize=1M tmpfs /var/example
# mount --make-private /var/example

3. Verify the mountpoint propagation is set to private:
$ findmnt -o+PROPAGATION | grep example

│ └─/var/example tmpfs tmpfs rw,relatime,size=1024k private

4. Perform an update to systemd:
# yum update systemd

5. Find that systemd has reset the administrator-set mountpoint propagation to shared:
$ findmnt -o+PROPAGATION | grep example

│ └─/var/example tmpfs tmpfs rw,relatime,size=1024k shared

(The same is true for mountpoints configured via systemd using .mount or .service definitions)
dmz

dmz

2019-02-28 10:11

reporter   ~0033916

(NB mkdir /var/example in example above, apologies, location is arbitrary, merely for demonstration purposes)

Issue History

Date Modified Username Field Change
2019-02-26 10:52 dmz New Issue
2019-02-26 18:15 JohnnyHughes Note Added: 0033908
2019-02-26 18:15 JohnnyHughes Status new => feedback
2019-02-26 18:17 TrevorH Note Added: 0033909
2019-02-28 10:08 dmz Note Added: 0033915
2019-02-28 10:08 dmz Status feedback => assigned
2019-02-28 10:11 dmz Note Added: 0033916