erl_boot_server(3erl) Erlang Module Definition erl_boot_server(3erl)NAME
erl_boot_server - Boot Server for Other Erlang Machines
DESCRIPTION
This server is used to assist diskless Erlang nodes which fetch all Erlang code from another machine.
This server is used to fetch all code, including the start script, if an Erlang runtime system is started with the -loader inet command
line flag. All hosts specified with the -hosts Host command line flag must have one instance of this server running.
This server can be started with the kernel configuration parameter start_boot_server .
The erl_boot_server can both read regular files as well as files in archives. See code(3erl) and erl_prim_loader(3erl) .
Warning:
The support for loading of code from archive files is experimental. The sole purpose of releasing it before it is ready is to obtain early
feedback. The file format, semantics, interfaces etc. may be changed in a future release.
EXPORTS
start(Slaves) -> {ok, Pid} | {error, What}
Types Slaves = [Host]
Host = atom()
Pid = pid()
What = term()
Starts the boot server. Slaves is a list of IP addresses for hosts which are allowed to use this server as a boot server.
start_link(Slaves) -> {ok, Pid} | {error, What}
Types Slaves = [Host]
Host = atom()
Pid = pid()
What = term()()
Starts the boot server and links to the caller. This function is used to start the server if it is included in a supervision tree.
add_slave(Slave) -> ok | {error, What}
Types Slave = Host
Host = atom()
What = term()
Adds a Slave node to the list of allowed slave hosts.
delete_slave(Slave) -> ok | {error, What}
Types Slave = Host
Host = atom()
What = void()
Deletes a Slave node from the list of allowed slave hosts.
which_slaves() -> Slaves
Types Slaves = [Host]
Host = atom()
Returns the current list of allowed slave hosts.
SEE ALSO init(3erl) , erl_prim_loader(3erl)Ericsson AB kernel 2.14.3 erl_boot_server(3erl)
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net_adm(3erl) Erlang Module Definition net_adm(3erl)NAME
net_adm - Various Erlang Net Administration Routines
DESCRIPTION
This module contains various network utility functions.
EXPORTS
dns_hostname(Host) -> {ok, Name} | {error, Host}
Types Host = atom() | string()
Name = string()
Returns the official name of Host , or {error, Host} if no such name is found. See also inet(3erl) .
host_file() -> Hosts | {error, Reason}
Types Hosts = [Host]
Host = atom()
Reason = term()
Reads the .hosts.erlang file, see the section Files below. Returns the hosts in this file as a list, or returns {error, Reason} if
the file could not be read. See file(3erl) for possible values of Reason .
localhost() -> Name
Types Name = string()
Returns the name of the local host. If Erlang was started with the -name command line flag, Name is the fully qualified name.
names() -> {ok, [{Name, Port}]} | {error, Reason}
names(Host) -> {ok, [{Name, Port}]} | {error, Reason}
Types Name = string()
Port = int()
Reason = address | term()
Similar to epmd -names , see epmd(1) . Host defaults to the local host. Returns the names and associated port numbers of the Erlang
nodes that epmd at the specified host has registered.
Returns {error, address} if epmd is not running. See inet(3erl) for other possible values of Reason .
(arne@dunn)1> net_adm:names().
{ok,[{"arne",40262}]}
ping(Node) -> pong | pang
Types Node = node()
Tries to set up a connection to Node . Returns pang if it fails, or pong if it is successful.
world() -> [node()]
world(Arg) -> [node()]
Types Arg = silent | verbose
This function calls names(Host) for all hosts which are specified in the Erlang host file .hosts.erlang , collects the replies and
then evaluates ping(Node) on all those nodes. Returns the list of all nodes that were, successfully pinged.
Arg defaults to silent . If Arg == verbose , the function writes information about which nodes it is pinging to stdout.
This function can be useful when a node is started, and the names of the other nodes in the network are not initially known.
Failure: {error, Reason} if host_file() returns {error, Reason} .
world_list(Hosts) -> [node()]
world_list(Hosts, Arg) -> [node()]
Types Hosts = [Host]
Host = atom()
Arg = silent | verbose
As world/0,1 , but the hosts are given as argument instead of being read from .hosts.erlang .
FILES
The .hosts.erlang file consists of a number of host names written as Erlang terms. It is looked for in the current work directory, the
user's home directory, and $OTP_ROOT (the root directory of Erlang/OTP), in that order.
The format of the .hosts.erlang file must be one host name per line. The host names must be within quotes as shown in the following exam-
ple:
^ (new line)
Ericsson AB kernel 2.14.3 net_adm(3erl)