/etc/machine-id changes at each boot on my recent Debian Jessie install.
The docs say it shouldn't:
The machine ID is usually generated from a random source during system installation and stays constant for all subsequent boots. Optionally, for stateless systems, it is generated during runtime at early boot if it is found to be empty.
(Unless my system is "stateless". Not sure what that is.)
I realized it because it creates a log entry everyday in my /etc repository using etckeeper.
mount command confirms it is not persistent:
# mount | grep machine-id
tmpfs on /etc/machine-id type tmpfs (ro,relatime,size=811524k,mode=755)
Is this an issue? Should I do anything about it?
I could add it to .gitignore to avoid the useless commits, but I'd be interested to know why it happens in the first place.
Edit: df and mount output
Not sure it matters at all but here it is:
I'm using a software RAID1. /dev/sda and /dev/sdc are mirrored into a 3 partition volume: /dev/md0p1 is swap, /dev/md0p2 is / and /dev/md0p3 is /home.
/dev/sdb is an old HD used for backups.
$ df
Sys. de fichiers blocs de 1K Utilisé Disponible Uti% Monté sur
/dev/md0p2 28703672 5011248 22211316 19% /
udev 10240 0 10240 0% /dev
tmpfs 811524 9360 802164 2% /run
tmpfs 2028804 836 2027968 1% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 2028804 0 2028804 0% /sys/fs/cgroup
/dev/sdb1 615189496 506132424 77784164 87% /mnt/bak
/dev/md0p3 928490588 506207060 375095888 58% /home
tmpfs 405764 4 405760 1% /run/user/119
tmpfs 405764 16 405748 1% /run/user/1000
$ mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,relatime,size=10240k,nr_inodes=504119,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,relatime,size=811524k,mode=755)
/dev/md0p2 on / type ext4 (rw,relatime,errors=remount-ro,data=ordered)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)
tmpfs on /etc/machine-id type tmpfs (ro,relatime,size=811524k,mode=755)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=22,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)
mqueue on /dev/mqueue type mqueue (rw,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
/dev/sdb1 on /mnt/bak type ext4 (rw,relatime,errors=remount-ro,data=ordered)
/dev/md0p3 on /home type ext4 (rw,relatime,data=ordered)
rpc_pipefs on /run/rpc_pipefs type rpc_pipefs (rw,relatime)
tmpfs on /run/user/119 type tmpfs (rw,nosuid,nodev,relatime,size=405764k,mode=700,uid=119,gid=127)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=405764k,mode=700,uid=1000,gid=1000)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,relatime)
