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CELLSERVDB(5)		      AFS File Reference		 CELLSERVDB(5)

       CellServDB - Lists the database server machines in AFS cells

       There are two versions of the CellServDB	file, both of which have the
       same format.  One version is used by an AFS client and lists all	of the
       database	server machines	in the local cell and any foreign cell that is
       to be accessible	from the local client machine.	The other version is
       used on servers and need	list only the database servers in the local
       cell; in	some configurations it can be a	link to	the same file the
       client uses.

   Client CellServDB
       Along with AFSDB	and SRV	entries	in DNS,	the client version of the
       CellServDB file lists the database server machines in the local cell
       and any foreign cell that is to be accessible from the local client
       machine.	Database server	machines run the Authentication	Server
       (optional), Backup Server (optional), Protection	Server,	and Volume
       Location	(VL) Server (the kaserver, buserver, ptserver, and vlserver)
       processes, which	maintain the cell's administrative AFS databases.

       The Cache Manager and other processes running on	a client machine use
       the list	of a cell's database server machines when performing several
       common functions, including:

       o   Fetching files. The Cache Manager contacts the VL Server to learn
	   the location	of the volume containing a requested file or

       o   Creating, viewing, and manipulating protection groups. The pts
	   command interpreter contacts	the Protection Server when users
	   create protection groups or request information from	the Protection

       o   Populating the contents of the fake root.afs	volume mounted at /afs
	   (or the alternative mount point specified in	cacheinfo) when	afsd
	   is run in "-dynroot"	mode.  The default contents of this directory
	   will	match the cells	listed in the client CellServDB	file.

       o   Authenticating users. Client-side authentication programs (such as
	   an AFS-modified login utility or the	klog command interpreter)
	   contact the Authentication Server to	obtain a server	ticket,	which
	   the AFS server processes accept as proof that the user is
	   authenticated. This only applies to AFS cells using the deprecated
	   Authentication Server instead of Kerberos v5	and aklog.

       The Cache Manager reads the CellServDB file into	kernel memory as it
       initializes, and	not again until	the machine next reboots or the	client
       service restarts. To enable users on the	local machine to continue
       accessing the cell correctly, update the	file whenever a	database
       server machine is added to or removed from a cell. To update the
       kernel-resident list of database	server machines	without	rebooting, use
       the fs newcell command.

       If the client attempts to access	an AFS cell not	listed in CellServDB
       and afsd	was started with the -afsdb option, the	Cache Manager will
       attempt a DNS SRV or AFSDB record lookup	and dynamically	add the
       database	server locations for that cell based on	the result of the DNS
       query.  If the -afsdb option was	not used, all AFS cells	that will be
       accessed	by a client machine must either	be listed in CellServDB	or
       added with the fs newcell command.

       The CellServDB file is in ASCII format and must reside in the
       /usr/local/etc/openafs directory	on each	AFS client machine. Use	a text
       editor to create	and maintain it.

       The client version of the CellServDB file is distinct from the server
       version,	which resides in the /usr/local/etc/openafs/server directory
       on each AFS server machine. The client version lists the	database
       server machines in every	AFS cell that the cell administrator wants the
       machine's users to be able to access, whereas the server	version	lists
       only the	local cell's database server machines.

   Server CellServDB
       The server version of the CellServDB file lists the local cell's
       database	server machines. These machines	run the	Authentication Server
       (optional), Backup Server (optional), Protection	Server,	and Volume
       Location	(VL) Server (the kaserver, buserver, ptserver, and vlserver)
       processes, which	maintain the cell's administrative AFS databases. The
       initial version of the file is created with the bos setcellname command
       during the installation of the cell's server machine, which is
       automatically recorded as the cell's first database server machine.
       When adding or removing database	server machines, be sure to update
       this file appropriately.	It must	reside in the
       /usr/local/etc/openafs/server directory on each AFS server machine. The
       database	server processes, in addition to the usual configuration
       allowing	each to	be elected synchronization site	and coordinate
       updates,	can be set up as readonly database clone servers. Such servers
       can never be elected as the synchronization site.

       The database server processes consult the CellServDB file to learn
       about their peers, with which they must maintain	constant connections
       in order	to coordinate replication of changes across the	multiple
       copies of each database.	The other AFS server processes consult the
       file to learn which machines to contact for information from the
       databases when they need	it.

       Although	the server CellServDB file is in ASCII format, do not use a
       text editor to alter it.	Instead	always use the appropriate commands
       from the	bos command suite:

       o   The bos addhost command to add a machine to the file.

       o   The bos listhosts command to	display	the list of machines from the

       o   The bos removehost command to remove	a machine from the file.

       In cells	that use the Update Server to distribute the contents of the
       /usr/local/etc/openafs/server directory,	it is customary	to edit	only
       the copy	of the file stored on the system control machine. Otherwise,
       edit the	file on	each server machine individually. For instructions on
       adding and removing database server machine, see	the OpenAFS Quick
       Start chapter on	installing additional server machines. Updates to the
       server CellServDB will trigger reloading	the cell server	configurations
       automatically in	the AFS	server processes.

   CellServDB Format
       Both CellServDB files have the same format:

       o   The first line begins at the	left margin with the greater-than
	   character (">"), followed immediately by the	cell's name without an
	   intervening space. Optionally, a comment can	follow any number of
	   spaces and a	octothorpe ("#"), perhaps to identify the organization
	   associated with the cell. A variant of this allows the definition
	   of a	linked cell: after the leading (">") and cell name, a space
	   and a second	cell name may be listed	before the optional spaces,
	   octothorpe and comment.

       o   Each	subsequent line	in the entry identifies	one of the cell's
	   database server machines, with the indicated	information in order:

	   o   The database server machine's IP	address	in dotted-decimal
	       format, optionally enclosed in square braces ("[")("]") to
	       define a	non-voting clone.

	   o   One or more spaces.

	   o   An octothorpe (#), followed by the machine's fully qualified
	       hostname	without	an intervening space. This number sign does
	       not indicate that the hostname is a comment. It is a required

       No extra	blank lines or newline characters are allowed in the file,
       even after the last entry. Their	presence can prevent the Cache Manager
       from reading the	file into kernel memory, resulting in an error

       For the client CellServDB, it may be desirable to make the client aware
       of a cell (so that it's listed by default in /afs when the -dynroot
       flag to afsd is in use, for instance) without specifying	the database
       server machines for that	cell.  This can	be done	by including only the
       cell line (starting with	">") and omitting any following	database
       server machine lines. afsd must be configured with the -afsdb option to
       use DNS SRV or AFSDB record lookups to locate database server machines.
       If the cell has such records and	the client is configured to use	them,
       this configuration won't	require	updates	to the client CellServDB file
       when the	IP addresses of	the database server machines change. maintains a list of the database server machines in
       all cells that have registered themselves as receptive to access	from
       foreign cells. When a cell's administrators change its database server
       machines, it is customary to register the change	with
       for inclusion in	this file. The file conforms to	the required
       CellServDB format, and so is a suitable basis for the CellServDB	file
       on a client machine.  You can download this file	from

       The following example shows entries for two cells in a client
       CellServDB file and illustrates the required format.

	  >	  # ABC	Corporation
	  >	  # ABC	Corporation Test Cell

       afsd(8),	bos_addhost(8),	bos_listhosts(8), bos_removehost(8),
       bos_setcellname(8), buserver(8),	fs_newcell(1), kaserver(8), klog(1),
       ptserver(8), vlserver(8), upclient(8), upserver(8)

       OpenAFS Quick Start

       IBM Corporation 2000. <> All Rights Reserved.

       This documentation is covered by	the IBM	Public License Version 1.0.
       It was converted	from HTML to POD by software written by	Chas Williams
       and Russ	Allbery, based on work by Alf Wachsmann	and Elizabeth Cassell.

OpenAFS				  2016-12-14			 CELLSERVDB(5)


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