This daemon acts as a name server on all hosts involved in
distributed Erlang computations. When an Erlang node
starts, the node has a name and it obtains an address from the host
OS kernel.
The name and the address are sent to the
epmd
daemon running on the local host.
In a TCP/IP environment, the address consists
of the IP address and a port number. The name of the node is
an atom on the form of Name@Node
.
The job of the epmd
daemon is to keep track of which
node name listens on which address. Hence, epmd
map
symbolic node names to machine addresses.
The daemon is started automatically by the Erlang start-up script.
The program epmd
can also be used for a variety of other
purposes, for example checking the DNS (Domain Name System)
configuration of a host.
epmd [-daemon]
Starts a name server as a daemon. If it has no argument, the
epmd
runs as a normal program with the controlling terminal
of the shell in which it is started. Normally, it should run as a
daemon.
epmd -names
Requests the names of the local Erlang nodes epmd
has
registered.
epmd -kill
Kills the epmd
process.
epmd -help
Write short info about the usage including some debugging options not listed here.
On some operating systems syslog will be used for
error reporting when epmd runs as an daemon. To enable
the error logging you have to edit /etc/syslog.conf (UNIX: , Windows:
)
file and add an entry
!epmd *&ld;TABs>/var/log/epmd.log
where <TABs> are real tab characters. Spaces will silently be ignored.