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    Command:

    CellServDB

    
    
    

    DESCRIPTION

           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:
    
           ?   Fetching files. The Cache Manager contacts the VL Server to learn
               the location of the volume containing a requested file or
               directory.
    
           ?   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
               Database.
    
           ?   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.
    
           ?   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
           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 /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:
    
           ?   The bos addhost command to add a machine to the file.
    
           ?   The bos listhosts command to display the list of machines from the
               file.
    
           ?   The bos removehost command to remove a machine from the file.
    
           In cells that use the Update Server to distribute the contents of the
           /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:
    
           ?   The first line begins at the left margin with the greater-than
    
               ?   One or more spaces.
    
               ?   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
                   field.
    
           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
           message.
    
           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.
    
           grand.central.org 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 grand.central.org
           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
           <http://grand.central.org/>.
    
    
    

    EXAMPLES

           The following example shows entries for two cells in a client
           CellServDB file and illustrates the required format.
    
              >abc.com        # ABC Corporation
              192.12.105.2         #db1.abc.com
              192.12.105.3         #db2.abc.com
              [192.12.107.3]       #db3.abc.com
              >test.abc.com abc.com   # ABC Corporation Test Cell
              192.12.108.57        #testdb1.abc.com
              192.12.108.55        #testdb2.abc.com
    
    
    

    SEE ALSO

           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
    
    
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