NSCD(8) Maintenance Commands and Procedures NSCD(8)

NAME

nscd - name service cache daemon

SYNOPSIS

/usr/sbin/nscd [-f configuration-file] [-g] [-e cachename, yes
| no] [-i cachename]

DESCRIPTION

The nscd daemon is a process that provides a cache for most name service
requests. The default configuration-file /etc/nscd.conf determines the
behavior of the cache daemon. See nscd.conf(5).


nscd provides caching for the passwd(5), group(5), hosts(5), ipnodes(5),
exec_attr(5), prof_attr(5), user_attr(5), ethers(5), rpc(5),
protocols(5), networks(5), bootparams(5), auth_attr(5), services(5),
netmasks(5), printers(5), project(5) databases through standard libc
interfaces, such as gethostbyname(3NSL), getipnodebyname(3SOCKET),
gethostbyaddr(3NSL), and others. Each cache has a separate time-to-live
for its data; modifying the local database (/etc/hosts, /etc/resolv.conf,
and so forth) causes that cache to become invalidated upon the next call
to nscd. The shadow file is specifically not cached. getspnam(3C) calls
remain uncached as a result.


nscd also acts as its own administration tool. If an instance of nscd is
already running, commands are passed to the running version
transparently.


When running with per-user lookups enabled (see nscd.conf(5)), nscd forks
one and only one child process (that is, a per-user nscd) on behalf of
the user making the request. The per-user nscd will use the credentials
of the user to open a per-user connection to the name repository
configured for the per-user style of lookups. The lookup will be
performed in the child process. The results are cached in the process and
are available only to the same user. The caches are managed exactly the
same as the main nscd daemon manages its own caches. Subsequent requests
from the user will be handled by that per-user nscd until it terminates.
The per-user nscd uses a configurable inactivity time-to-live (TTL) value
and terminates itself after the inactivity TTL expires.


The maximum number of per-user nscds that can be created by the main nscd
is configurable (see nscd.conf(5)). After the maximum number of them are
created, the main nscd will use an LRU algorithm to terminate less active
child nscds as needed.


The main nscd daemon creates, monitors, and manages all the child nscds.
It creates a user's own nscd upon receiving the user's first per-user
lookup. When the nscd daemon is started, if per-user lookups are enabled,
it checks to ensure all conditions are met before getting ready to create
a per-user nscd. When the daemon is stopped, it terminates all the per-
user nscds under its control.


Per-user nscds use the same configuration as the main nscd. They read and
use the same default configuration file or the one specified with the -f
command line option. Once the configuration is read, the per-user nscd
will use it for its entire lifetime.

OPTIONS

Several of the options described below require a cachename specification.
Supported values for cachename are: passwd, group, hosts, ipnodes,
exec_attr, prof_attr, user_attr, ethers, rpc, protocols, networks,
bootparams, auth_attr, services, netmasks, printers, and project.

-f configuration-file

Causes nscd to read its configuration data from the specified file.


-g

Prints current configuration and statistics to standard output. This
is the only option executable by non-root users.


-e cachename, yes|no

Enables or disables the specified cache.


-i cachename

Invalidate the specified cache.

EXAMPLES

Example 1: Stopping and restarting the nscd daemon.

example# svcadm disable system/name-service-cache

example# svcadm enable system/name-service-cache

FILES

/etc/nscd.conf
Determines athe behavior of the cache daemon

SEE ALSO

svcs(1), getspnam(3C), gethostbyname(3NSL), getipnodebyname(3SOCKET),
auth_attr(5), bootparams(5), ethers(5), exec_attr(5), group(5), hosts(5),
netmasks(5), networks(5), nscd.conf(5), nsswitch.conf(5), passwd(5),
printers(5), prof_attr(5), project(5), protocols(5), rpc(5), services(5),
user_attr(5), attributes(7), svcadm(8)

NOTES

The output from the -g option to nscd is subject to change. Do not rely
upon it as a programming interface.


The nscd service is managed by the service management facility, smf(7),
under the service identifier:

svc:/system/name-service-cache


Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using svcadm(8). The service's
status can be queried using the svcs(1) command.

March 6, 2017 NSCD(8)