Service appstream-sync-cache.service failed in SLES15 SP5

This document (000021235) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 15 SP5

Situation

After an OS migration from SUSE 15 SP4 to SUSE 15 SP5, the appstream-sync-cache.service systemd service cannot be started. The messages are similar to the following:

# /bin/systemctl status 'appstream-sync-cache.service'
× appstream-sync-cache.service - Synchronize AppStream metadata from repositories into AS-cache
     Loaded: loaded (/usr/lib/systemd/system/appstream-sync-cache.service; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Fri 2023-09-29 18:56:23 CEST; 5min ago
    Process: 965 ExecStart=/usr/bin/zypper appstream-cache (code=exited, status=1/FAILURE)

Sep 29 18:56:22 sles15-sp5 systemd[1]: Starting Synchronize AppStream metadata from repositories into AS-cache...
Sep 29 18:56:22 sles15-sp5 zypper[1158]: Forcing resync of AppStream metadata from repo cache into /var/cache/app-info
Sep 29 18:56:23 sles15-sp5 zypper[965]: '/usr/lib/zypper/commands/zypper-appstream-cache' exited with status 1
Sep 29 18:56:23 sles15-sp5 systemd[1]: appstream-sync-cache.service: Control process exited, code=exited, status=1/FAILURE
Sep 29 18:56:23 sles15-sp5 systemd[1]: appstream-sync-cache.service: Failed with result 'exit-code'.
Sep 29 18:56:23 sles15-sp5 systemd[1]: Failed to start Synchronize AppStream metadata from repositories into AS-cache.

The libzypp-plugin-appdata and appstream-glib packages are installed from the Desktop Applications Module 15 SP5 module.

The following timeout was observed:

sles15-sp5:~ # systemctl show appstream-sync-cache.service | grep TimeoutStart
TimeoutStartUSec=1min 30s
TimeoutStartFailureMode=terminate

The appstream-sync-cache.service times out when attempting to start.

sles15-sp5:~ # time systemctl restart appstream-sync-cache.service  
Job for appstream-sync-cache.service failed because a timeout was exceeded.
See "systemctl status appstream-sync-cache.service" and "journalctl -xeu appstream-sync-cache.service" for details.

real    1m30.209s   <---
user    0m0.011s
sys     0m0.003s

Resolution

Run the command /usr/bin/zypper appstream-cache manually and restart the service.

sudo /usr/bin/zypper appstream-cache
sudo systemctl restart appstream-sync-cache.service

Cause

The service should run once and be automatically denied by pre-conditions after the resync of the AppStream metadata from the repo cache into /var/cache/app-info. In the example provided in the Situation section of this document, the service could not finish on time and reached the default systemd timeout of 90 seconds.

The appstream meta cache is used by software centers (such as GNOME Software, KDE Discover, appstream-util).

Additional Information

The systemd unit file /usr/lib/systemd/system/appstream-sync-cache.service calls:

ExecStart=/usr/bin/zypper appstream-cache

The "appstream-cache" is not found within zypper man page, as it is a zypper subcomand. It can be accessed by running zypper help appstream-cache.

The following systemd drop-in file was created for troubleshooting purposes:

/etc/systemd/system/appstream-sync-cache.service.d/override.conf

Example of the contents of the override.conf file:

[Service]
ExecStart=
ExecStart=/usr/bin/strace -f -o /tmp/appstream.log /usr/bin/zypper appstream-cache

Send the /tmp/appstream.log to SUSE Technical Support for further investigation.

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