Re: [chrony-users] Debian stretch read only rootfs?

[Matthew Eshleman <matthew@xxxxxxxxxxxxxxxxxxxxxxxx>]

Thank you to all responding. Sadly still not working.

I added basically all of the indicated folders as tmpfs:

~# df
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root         257664 257664         0 100% /
devtmpfs          167400      0    167400   0% /dev
tmpfs             167912      0    167912   0% /dev/shm
tmpfs             167912    980    166932   1% /run
tmpfs               5120      8      5112   1% /run/lock
tmpfs             167912      0    167912   0% /sys/fs/cgroup
tmpfs               1024      0      1024   0% /run/chrony
tmpfs               1024      0      1024   0% /var/db/chrony
tmpfs               1024      4      1020   1% /var/lib/dhcp
tmpfs               2048     20      2028   1% /run_etc_tmpfs
tmpfs             167912      0    167912   0% /tmp
tmpfs               1024      0      1024   0% /var/volatile/lib/chrony
tmpfs               1024      0      1024   0% /var/lib/chrony
tmpfs               1024      0      1024   0% /var/spool
tmpfs               1024     12      1012   2% /var/log
overlay             2048     20      2028   1% /etc
/dev/mmcblk0p5    122835   2669    113613   3% /media/settings

But the end results are the same. Same failure.. I've also confirmed that systemctl restart fails too, same message as before.

Additionally, my rev of debian apparently does not show the ReadWritePaths attribute. Perhaps we are just too old at this point?

I also manually ran chronyd, which seemed to run/start. The logs/journal does show:

Feb 04 17:33:51 M chronyd[1888]: chronyd version 3.0 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SECHASH +SIGND +ASYNCDNS +IPV6 -DEBUG)
Feb 04 17:33:51 M chronyd[1888]: Wrong permissions on /run/chrony
Feb 04 17:33:51 M chronyd[1888]: Disabled command socket /run/chrony/chronyd.sock

Any further thoughts? 

Best regards,

Matthew

On Fri, Feb 4, 2022 at 10:39 AM Jan Mikkelsen <janm@xxxxxxxxxxxxxxxxxxx> wrote:

Hello,

For what it’s worth, I am running chrony on a FreeBSD system with a read-only root filesystem (including read-only /etc) just fine. The places chrony writes on this system are /var/run/chrony and /var/db/chrony.

Regards,

Jan M.

On 4 Feb 2022, at 17:06, Matthew Eshleman <matthew@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Hello all,

I've been experimenting with chrony for an embedded linux system and we have decided to move forward, adding NTP as a feature to this device, using chrony. Previously this device only supported human manual time entry. All experiments to-date have been on a development unit with a fairly normal read/write debian rootfs.

This device is currently using debian stretch, and we use a multistrap approach to generate our rootfs, which is then packaged into a read only rootfs using squashfs for our production configuration.

In my attempts so far, chrony fails to start. We have a ramfs overlay for /etc/ and I added one for /var/lib/chrony as well. The logs/journal did not point me to the exact folder/file that is blocking chrony from starting with a read only root filesystem, and I didn't find specific hints via google (except for some redhat patch, that I do not believe applies here...)

Additionally, I configured chrony to use a drift file that is on a separate read/write partition.

What additional files/folders does chrony need to be read/write?

Logs and such are below:

Feb 04 15:19:34 M systemd[1]: Started Raise network interfaces.
Feb 04 15:19:34 M systemd[1]: Reached target Network.
Feb 04 15:19:34 M systemd[1]: chrony.service: Failed to run 'start' task: Read-only file system
Feb 04 15:19:34 M systemd[1]: Failed to start chrony, an NTP client/server.
Feb 04 15:19:35 M systemd[1]: chrony.service: Unit entered failed state.
Feb 04 15:19:35 M systemd[1]: chrony.service: Failed with result 'resources'.

systemctl status chrony
● chrony.service - chrony, an NTP client/server
   Loaded: loaded (/lib/systemd/system/chrony.service; enabled; vendor preset: e
   Active: failed (Result: resources)
     Docs: man:chronyd(8)
           man:chronyc(1)
           man:chrony.conf(5)

~# df
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root         257664 257664         0 100% /
devtmpfs          167400      0    167400   0% /dev
tmpfs             167912      0    167912   0% /dev/shm
tmpfs             167912    960    166952   1% /run
tmpfs               5120      8      5112   1% /run/lock
tmpfs             167912      0    167912   0% /sys/fs/cgroup
tmpfs               1024      0      1024   0% /var/lib/chrony
tmpfs               2048     16      2032   1% /run_etc_tmpfs
tmpfs             167912      0    167912   0% /tmp
tmpfs               1024      4      1020   1% /var/lib/dhcp
overlay             2048     16      2032   1% /etc
/dev/mmcblk0p5    122835   2612    113670   3% /media/settings

chronyd version 3.0 (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SECHASH +SIGND +ASYNCDNS +IPV6 -DEBUG)

Thank you very much for any pointers, tips, etc.

Best regards,

Matthew