Description

pvmd3 is a daemon process which coordinates hosts in a virtual machine. One pvmd must run on each host in the group. They provide the communication and process control functions needed by the user's PVM processes. The daemon can be started manually with a host file argument that will automatically start the remote pvmds. The local and remote pvmds can also be started from the PVM console program pvm.

The name of the daemon executable is pvmd3. It is usually started by a shell script, $PVM_ROOT/lib/pvmd.

Local daemon may also be started by the scilab instruction pvm_start() and remote daemons may also be started by the scilab function pvm_addhosts

Options

The following options may be specified on the command line when starting the master pvmd or PVM console:

The following options are used by the master pvmd when starting slaves and are only of interest to someone writing a hoster. Don't just go using them, now.

Lines beginning with a splat ( # ), optionally preceded by whitespace, are ignored.

A simple host file might look like:

# my first host file
thud
fred
wilma
barney
betty
   
    

This specifies the names of five hosts to be configured in the virtual machine. The master pvmd for a group is started by hand on the localhost, and it starts slaves on each of the remaining hosts using the rsh or rexec command. The master host may appear on any line of the hostfile, but must have an entry. The simple format above works fine if you have the same login name on all five machines and the name of the master host in your .rhosts files on the other four. There are several host file options available:

A dollar sign ( $ ) in an option introduces a variable name, for example $PVM_ARCH. Names are expanded from environment variables by each pvmd. Each of the flags above has a default value. These are:

You can change these by adding a line with a star ( * ) in the first field followed by the options, for example:

Host options can be set without starting the hosts automatically. Information on host file lines beginning with `&' is stored, but the hosts are not started until added using pvm_addhosts().

Example hostfile:

# hostfile for testing on various platforms fonebone refuge
# installed in /usr/local/here
sigi.cs
     dx=/usr/local/pvm3/lib/pvmd # borrowed accts, "guest", don't trust fonebone 
   
    

Manual STARTUP

When adding a host with this option set you will see on the tty of the pvmd:

*** Manual startup ***
   
    

Login to "honk" and type:

$PVM_ROOT/lib/pvmd -S -d0 -nhonk 1 80a9ca95:0cb6 4096 2 80a95c43:0000 Type response:
   
    

after typing the given command on host honk, you should see a line like:

ddpro<2312> arch<ALPHA> ip<80a95c43:0a8e> mtu<4096>
   
    

type this line on the tty of the master pvmd. You should then see:

Thanks
   
    

and the two pvmds should be able to communicate. Note you can't start the master using the console or background it when using this option.

Stopping PVMD3

The preferred method of stopping all the pvmds is to give the halt command in the PVM console. This kills all pvm tasks, all the remote daemons, the local daemon, and finally the console itself. If the master pvmd is killed manually it should be sent a SIGTERM signal to allow it to kill the remote pvmds and clean up various files. The pvmd can be killed in a manner that leaves the file /tmp/pvmd.uid behind on one or more hosts. Uid is the numeric user ID (from /etc/passwd) of the user. This will prevent PVM from restarting on that host. Deletion of this file will fix this problem:

rm `( grep $user /etc/passwd || ypmatch $user passwd ) | \
 awk -F: `{print "/tmp/pvmd."$3; exit}'`