SSS_CACHE(8) SSSD Manual pages SSS_CACHE(8)
NAME
sss_cache - perform cache cleanup
SYNOPSIS
sss_cache [options]
DESCRIPTION
sss_cache invalidates records in SSSD cache. Invalidated records are
forced to be reloaded from server as soon as related SSSD backend is
online. Options that invalidate a single object only accept a single
provided argument.
OPTIONS
-E,--everything
Invalidate all cached entries.
-u,--user login
Invalidate specific user.
-U,--users
Invalidate all user records. This option overrides invalidation of
specific user if it was also set.
-g,--group group
Invalidate specific group.
-G,--groups
Invalidate all group records. This option overrides invalidation of
specific group if it was also set.
-n,--netgroup netgroup
Invalidate specific netgroup.
-N,--netgroups
Invalidate all netgroup records. This option overrides invalidation
of specific netgroup if it was also set.
-s,--service service
Invalidate specific service.
-S,--services
Invalidate all service records. This option overrides invalidation
of specific service if it was also set.
-a,--autofs-map autofs-map
Invalidate specific autofs maps.
-A,--autofs-maps
Invalidate all autofs maps. This option overrides invalidation of
specific map if it was also set.
-h,--ssh-host hostname
Invalidate SSH public keys of a specific host.
-H,--ssh-hosts
Invalidate SSH public keys of all hosts. This option overrides
invalidation of SSH public keys of specific host if it was also
set.
-r,--sudo-rule rule
Invalidate particular sudo rule.
-R,--sudo-rules
Invalidate all cached sudo rules. This option overrides
invalidation of specific sudo rule if it was also set.
-d,--domain domain
Restrict invalidation process only to a particular domain.
-?,--help
Display help message and exit.
EFFECTS ON THE FAST MEMORY CACHE
sss_cache also invalidates the memory cache. Since the memory cache is
a file which is mapped into the memory of each process which called
SSSD to resolve users or groups the file cannot be truncated. A special
flag is set in the header of the file to indicate that the content is
invalid and then the file is unlinked by SSSD's NSS responder and a new
cache file is created. Whenever a process is now doing a new lookup for
a user or a group it will see the flag, close the old memory cache file
and map the new one into its memory. When all processes which had
opened the old memory cache file have closed it while looking up a user
or a group the kernel can release the occupied disk space and the old
memory cache file is finally removed completely.
A special case is long running processes which are doing user or group
lookups only at startup, e.g. to determine the name of the user the
process is running as. For those lookups the memory cache file is
mapped into the memory of the process. But since there will be no
further lookups this process would never detect if the memory cache
file was invalidated and hence it will be kept in memory and will
occupy disk space until the process stops. As a result calling
sss_cache might increase the disk usage because old memory cache files
cannot be removed from the disk because they are still mapped by long
running processes.
A possible work-around for long running processes which are looking up
users and groups only at startup or very rarely is to run them with the
environment variable SSS_NSS_USE_MEMCACHE set to "NO" so that they
won't use the memory cache at all and not map the memory cache file
into the memory. In general a better solution is to tune the cache
timeout parameters so that they meet the local expectations and calling
sss_cache is not needed.
SEE ALSO
sssd(8), sssd.conf(5), sssd-ldap(5), sssd-krb5(5), sssd-simple(5),
sssd-ipa(5), sssd-ad(5), sssd-files(5), sssd-sudo(5), sssd-session-
recording(5), sss_cache(8), sss_debuglevel(8), sss_obfuscate(8),
sss_seed(8), sssd_krb5_locator_plugin(8), sss_ssh_authorizedkeys(8),
sss_ssh_knownhostsproxy(8), sssd-ifp(5), pam_sss(8). sss_rpcidmapd(5)
sssd-systemtap(5)
AUTHORS
The SSSD upstream - https://github.com/SSSD/sssd/
SSSD 02/09/2025 SSS_CACHE(8)
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