ypfiles(5yp)ypfiles(5yp)Nameypfiles - Yellow Pages data base and directory structure
Description
The Yellow Pages (YP) data base lookup service uses a data base of
files in the directory hierarchy. A data base consists of two files,
created by calls to the library package. One has the filename exten‐
sion and the other has the filename extension For instance, the data
base named is implemented by the pair of files and
A data base served by YP is called a YP map. A YP domain is a named
set of YP maps. Each YP domain is implemented as a subdirectory of
containing the maps. The number of YP domains that can exist is unlim‐
ited. Each domain can contain any number of maps.
The YP maps are not required by the YP lookup service, although they
may be required for the normal operation of other parts of the system.
The YP lookup service serves all maps. If the map exists in a given
domain and a client asks about it, YP will serve it. There is, how‐
ever, a set of default maps that the YP service serves. The files rep‐
resenting these maps are listed in this description under Files.
For a map to be accessible consistently, it must exist on all YP
servers that serve the domain. To provide data consistency between the
replicated maps, an entry to execute the command periodically should be
made in the file on each slave server. More information on this topic
is in An entry in the file must not exist, either on a YP master server
or on a pure YP client machine.
The YP maps should contain two distinguished key-value pairs. The
first is the key YP_LAST_MODIFIED, whose value is a 10-character ASCII
order number. The order number should be the UNIX time in seconds when
the map was built. The second key is YP_MASTER_NAME, with the name of
the YP master server as a value. The command generates both key-value
pairs automatically. A map that does not contain both key-value pairs
can be served by the YP, but the process will not be able to return
values for ``Get order number'' or ``Get master name'' requests. In
addition, values of these two keys are used by when it transfers a map
from a master YP server to a slave.
Before they can be properly accessed, the YP maps must be initially set
up for both masters and slaves by using the function. Further, YP maps
must be generated and modified only at the master server location.
Copies of the master server YP maps can then be transferred to the
slave servers using the function. If is unable to determine a map's
location, or if it is unable to determine whether the local copy is
more recent than the master copy, extra command line switches must be
set when it is executed.
After the server data bases are set up, the contents of some maps may
change. In general, some ASCII source version of the data base exists
on the master. This version should be changed with a standard text
editor. The update is incorporated into the YP map and is propagated
from the master to the slaves by running All maps must have entries in
If a YP map is added, the must be edited to support the new map. The
makefile uses to generate the YP map on the master, and to propagate
the changed map to the slaves. The command is a client of the map
ypservers, which lists all of the YP servers.
FilesSee Alsomakedbm(8yp), rpcinfo(8nfs), ypmake(8yp), yppoll(8yp), yppush(8yp),
ypserv(8yp), ypsetup(8yp), ypxfr(8yp)ypfiles(5yp)
