glbd(1M)

NAME

glbd − Global Location Broker Daemon

SYNOPSIS

/etc/ncs/glbd [−create {−first [−family family_name] | −from host_name}] [−change_family family_name] [−listen family_list] [−version]

DESCRIPTION

The Global Location Broker (GLB), part of the Network Computing System (NCS), helps clients locate servers on a network or internet. The GLB database stores the locations (that is, the network addresses and port numbers) where server processes are running. A daemon maintains this database and provides access to it.

There are two versions of the GLB daemon: glbd and nrglbd. The replicatable version, glbd, is provided only for Domain/OS, HP-UX, SunOS, and ULTRIX systems. For other systems, the non-replicatable version, nrglbd, is provided. The two versions of the daemon should not coexist on a given network. (For HP-UX systems, which may have both glbd and nrglbd, the use of only glbd is strongly recommended; only glbd is described in this manual entry.

The GLB database can be replicated to increase its availability. Copies of the database can exist on several hosts, with a glbd running on each of those hosts to maintain the consistency of the database replicas. (In an internet, at least one glbd must run in each network.) Each replica of the GLB keeps a list of all the other GLB replicas. drm_admin(1M) administers the replication of the GLB database and the replica list.

Currently, glbd supports both the DARPA IP and Domain DDS network protocols. A GLB replica can allow access to its database from both IP and DDS clients. However, when communicating with each other to maintain replication of the GLB database, GLB replicas should use only one protocol family. You choose which family the GLBs will use. In an internet, all routing nodes must support this family.

If a set of GLB replicas includes any HP-UX, SunOS, or ULTRIX systems, all replicas must use IP protocols to communicate with each other. A replica running on a Domain/OS system can communicate with other replicas via IP protocols but still provide lookup and update services to its clients via both IP and DDS protocols.

Running glbd on HP-UX Systems

On HP-UX systems, the GLB communicates only via IP protocols. A Local Location Broker daemon (llbd) must be running on the local host when glbd is started.

Typically, the llbd and glbd processes are started in background at boot time from /etc/netncsrc; if the START_GLBD variable in netncsrc is set to 1, a glbd will be started. To start the llbd and glbd daemons by hand, you must be root.

OPTIONS

−create Create a replica of the GLB. This option creates a GLB database in addition to starting a broker process. It must be used with either −first or −from.

−first This option can be used only with the −create option. Use it to create the first replica (that is, the very first instance) of the GLB on your network or internet.

−family family_name
This option can be used only in conjunction with the −first option. It specifies the address family that the first GLB replica will use to identify itself on the replica list. Any subsequently created replicas must use this family to communicate with this replica. Currently, family_name can be either ip or dds. If this option is not used, the replica will be identified on the replica list by its IP address.

−from host_name
This option can be used only with the −create option. Use it to create additional replicas of the GLB. A replica of the GLB must exist at host_name. The database and replica list for the new replica are initialized from those at host_name. The replica at host_name adds an entry for the new replica to its replica list and propagates the entry to the other GLB replicas.

A host_name takes the form family:host, where the host can be specified either by its name or by its network address. For example, ip:bertie, ip:#192.5.5.5, dds://jeeves, and dds:#959a.940f are acceptable host names.

The new replica will use the same address family as host_name in identifying itself on the replica list. For example, if host_name is an IP address, the new replica will be listed by its IP address on the replica list.

−change_family family_name
Use this option only if network reconfigurations require that you change the address family of every GLB replica; see the discussion in the DESCRIPTION section. Currently, family_name can be either ip or dds. (If a GLB replica runs on an HP-UX host, its address family must be IP.)

For a procedure to change all of your GLB replicas from one address family to another, see Managing NCS Software.

−listen family_list
This option restricts the address families on which a GLB listens. Use it only if you are creating a special configuration where access to a GLB is restricted to a subset of hosts in the network or internet.

The family_list is a list of the address families on which the GLB will listen. Names in this list are separated by spaces. Possible family names include ip and dds.

The GLB will always listen for requests from the family by which it is listed on the replica list, even if that family is not specified in family_list.

If glbd is started without the −listen option, the GLB will listen on all address families that are supported both by NCS and by the local host. On Domain/OS systems, this set of families always includes dds and may also include ip. On most other systems, including HP-UX systems, ip is currently the only family.

−version Display the version of NCK that this glbd belongs to, but do not start the daemon.

EXAMPLES

Create and start for the first time the first replica of the GLB on this network or internet:

$ /etc/ncs/glbd −create −first &

Start for the first time a subsequent replica of the GLB, initializing its database from host jeeves:

$ /etc/ncs/glbd −create −from ip:jeeves &

Restart an existing replica of the GLB:

$ /etc/ncs/glbd &

FILES

On Domain/OS systems, glbd writes diagnostic output to the file `node_data/system_logs/glb_log. On other UNIX systems, including HP-UX systems, the log file is /etc/ncs/glb_log.

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