pvmd3PVM - Online in the Cloud

PROGRAM:

NAME

pvmd, pvmd3 - PVM daemon

SYNOPSIS

pvmd [ -options ] [ hostfile ]

DESCRIPTION

Pvmd3 is a daemon process which coordinates unix hosts in a virtual machine. One pvmd3
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.

[v3.4 and later] Before running pvmd3, pvmd sources any commands in $HOME/.pvmprofile if
this file exists.

OPTIONS

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

-dmask Set pvmd debug mask. Used to debug the pvmd or libpvm (not intended to be used to
debug application programs). Mask is the sum of the following bits and can be
specified in hexadecimal (0x...), octal (0...) or decimal:
Bit Information
0x1 Packet routing
0x2 Message routing and entry points
0x4 Task state
0x8 Slave pvmd startup
0x10 Host table updates
0x20 Select loop (below packet layer)
0x40 IP network
0x80 Multiprocessor nodes
0x100 Resource manager interface
0x200 Application (messages with no destination, etc.)
0x400 Wait contexts
0x800 Shared memory operations
0x1000 Semaphores
0x2000 Locks
0x4000 Message route control

-nname Specify an alternate hostname for the master pvmd to use. Useful when
gethostname() returns a name not assigned to any network interface.

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.

-s Start pvmd in slave mode. Hostfile cannot be used, five additional parameters must
be supplied: master pvmd index, master IP, master MTU, slave pvmd index, and slave
IP.

-S Same as -s, but slave pvmd doesn't wait for its stdin to be closed after printing
its parameters. Used for manual startup.

-f Slave doesn't fork after configuration (useful if the slave is to be controlled or
monitored by some process).

HOST FILE FORMAT

Each host in the virtual machine must have an entry in the host file. 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 host file. Host names cannot be numeric (IP) addresses, because they are
passed to rsh and rexec(), which usually don't accept addresses.

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:

lo=NAME Specifies an alternate login name (NAME) to use.

so=pw This is necessary when the remote host cannot trust the master. Causes
the master pvmd to prompt for a password for the remote host in the tty
of the pvmd (note you can't start the master using the console or
background it when using this option) you will see:
Password (honk.cs.utk.edu:manchek):
you should type your password for the remote host. The startup will then
continue as normal.

dx=FILE Specifies the path of the pvmd executable. FILE may be a simple
filename, an absolute pathname, or a path relative to the user's home
directory on the remote host. This is mainly useful to aid in debugging
new versions of PVM, but may have other uses.

ep=PATH Specifies a path for the pvmd to search for executable program components
when spawning a new process. The path may have multiple elements,
separated by colons ( : ).

wd=PATH Specifies a working directory in which all spawned tasks on this host
will execute.

sp=VALUE Specifies the relative computational speed of this host compared to other
hosts in the configuration. VALUE is an integer in the range [1 -
1000000]

bx=PATH Specifies the debugger program path. Note: the environment variable
PVM_DEBUGGER can also be set.

ip=NAME Specifies an alternate IP address to use for the host. As with host
names (when ip= is not used), the address must be a host name, not a
numeric address, because it is passed to rsh and rexec(). This option
allows one to pick a specific network interface for a machine without
using the interface's name. It can also be used to create a virtual
machine using symbolic (instead of actual) host names.

so=ms Rarely used. Causes the master pvmd to request user to manually perform
the startup of a pvmd on a slave host when rsh and rexec network services
are disabled but IP connectivity exists. See section "MANUAL STARTUP".

id=VMID A new feature in PVM 3.4.4 is the concept of a "Virtual Machine ID". You
can now set the VMID to an arbitrary string and this will distinguish and
allow multiple virtual machines to run on the same set of hosts under the
same userid. (This feature was originally introduced by SGI in their
commercial PVM product, and has now been generalized for the public PVM
system.) This feature seems to be something that people often want, and
the "id=" hostfile option (or $PVM_VMID environment variable) is the
cleanest way to provide this functionality, rather than overloading the
SHAREDTMP compiler flag and other internals.

*** Make Sure *** that you appropriately set the $PVM_VMID environment
variable in any shells from which PVM application tasks or the "pvm"
console will be run, or else they won't know which virtual machine to
attach to!

By default, all hosts which are added to the virtual machine will inherit
the same VMID. If hosts are added to the virtual machine which are
running older versions of PVM (prior to 3.4.4), then the VMID will be
ignored for those hosts, and hence these machines can only be added to
one virtual machine for the given user. The VMID need not be consistent
on every host in a virtual machine (although this is not necessarily
advisable).

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:
lo The loginname on the master host.
so Nothing
dx $PVM_ROOT/lib/pvmd (or environment variable PVM_DPATH)
ep $HOME/pvm3/bin/$PVM_ARCH:$PVM_ROOT/bin/$PVM_ARCH
wd $HOME
sp 1000
bx $PVM_ROOT/lib/debugger

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

* lo=afriend so=pw

This sets new default values for 'lo' and 'so' for the remainder of the host file, or
until the next '*' line. Options set on the last '*' line also apply to hosts added
dynamically using pvm_addhosts().

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 host file:
# host file 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
* lo=guest so=pw
sn666.jrandom.com
cubie.misc.edu
# really painful one, must start it by hand and share a homedir
& igor.firewall.com lo=guest2 so=ms ep=bob/pvm3/bin/$PVM_ARCH

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.

OVERLOADING HOSTS

You can force PVM to overload a host (start more than one pvmd on it) by putting a '$'
before the host name in the host file. This is not recommended unless you know what
you're doing and have a good reason for it. You must build the PVM source with option
OVERLOADHOST defined for it to work.

You may also need to use the ip= hostfile option to define several names with the same IP
address. If two or more hosts in a PVM have the same name, they cannot be identified
uniquely.

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}'`

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