/usr/share/perl5/Net/OpenSSH/Parallel.pm is in libnet-openssh-parallel-perl 0.12-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 | package Net::OpenSSH::Parallel;
our $VERSION = '0.12';
use strict;
use warnings;
use Carp qw(croak carp);
use Net::OpenSSH;
use Net::OpenSSH::Parallel::Constants qw(:error :on_error);
use POSIX qw(WNOHANG);
use Time::HiRes qw(time);
use Scalar::Util qw(dualvar);
our $debug;
sub new {
my ($class, %opts) = @_;
my $max_workers = delete $opts{workers};
my $max_conns = delete $opts{connections};
my $reconnections = delete $opts{reconnections};
my $on_error = delete $opts{on_error};
if ($max_conns) {
if ($max_workers) {
$max_conns < $max_workers and
croak "connections ($max_conns) < workers ($max_workers)";
}
else {
$max_workers = $max_conns;
}
}
%opts and croak "unknonwn option(s): ". join(", ", keys %opts);
my $self = { joins => {},
hosts => {},
host_by_pid => {},
ssh_master_by_pid => {},
in_state => {
connecting => {},
ready => {},
running => {},
done => {},
waiting => {},
suspended => {},
join_failed => {},
},
connected => { suspended => {},
waiting => {},
join_failed => {},
},
joins => {},
max_workers => $max_workers,
max_conns => $max_conns,
num_conns => 0,
reconnections => $reconnections,
on_error => $on_error,
};
bless $self, $class;
$self;
}
my %debug_channel = (api => 1, state => 2, select => 4, at => 8,
action => 16, join => 32, workers => 64,
connect => 128, conns => 256, error => 512);
sub _debug {
my $channel = shift;
my $bit = $debug_channel{$channel}
or die "internal error: bad debug channel $channel";
if ($debug & $debug_channel{$channel}) {
print STDERR sprintf("%6.3f", (time - $^T)), "| ",
join('', map { defined($_) ? $_ : '<undef>' } @_), "\n";
}
}
sub add_host {
my $self = shift;
my $label = shift;
$label =~ /([,*!()<>\/{}])/ and croak "invalid char '$1' in host label";
my %opts = (@_ & 1 ? (host => @_) : @_);
$opts{host} = $label unless defined $opts{host};
$opts{batch_mode} = 1 unless defined $opts{batch_mode};
my $on_error = delete $opts{on_error};
my $reconnections = delete $opts{reconnections};
my $host = { label => $label,
workers => 1,
opts => \%opts,
ssh => undef,
state => 'done',
queue => [],
on_error => $on_error,
reconnections => $reconnections,
};
$self->{hosts}{$label} = $host;
$debug and _debug(api => "[$label] added ($host)");
$self->{in_state}{done}{$label} = 1;
$debug and _debug(state => "[$label] state set to done");
}
sub _set_host_state {
my ($self, $label, $state) = @_;
my $host = $self->{hosts}{$label};
my $old = $host->{state};
delete $self->{in_state}{$old}{$label}
or die "internal error: host $label is in state $old but not in such queue";
delete $self->{connected}{$old}{$label}
if ($old eq 'suspended' or $old eq 'waiting' or $old eq 'join_failed');
$self->{in_state}{$state}{$label} = 1;
$host->{state} = $state;
$debug and _debug(state => "[$label] state changed $old --> $state");
if ($host->{ssh} and ($state eq 'suspended' or
$state eq 'waiting' or
$state eq 'join_failed')) {
$self->{connected}{$state}{$label} = 1;
$debug and _debug(state => "[$label] host is connected");
}
}
my %sel2re_cache;
sub _selector_to_re {
my ($self, $part) = @_;
$sel2re_cache{$part} ||= do {
$part = quotemeta $part;
$part =~ s/\\\*/.*/g;
qr/^$part$/;
}
}
sub _select_labels {
my ($self, $selector) = @_;
my %sel;
my @parts = split /\s*,\s*/, $selector;
for (@parts) {
my $re = $self->_selector_to_re($_);
$sel{$_} = 1 for grep $_ =~ $re, keys %{$self->{hosts}};
}
my @labels = keys %sel;
$debug and _debug(select => "selector($selector) --> [", join(', ', @labels), "]");
return @labels;
}
sub all { shift->push('*', @_) }
my %push_action_alias = (get => 'scp_get',
put => 'scp_put',
psub => 'parsub',
cmd => 'command');
my %push_min_args = ( here => 1,
goto => 1,
stop => 0,
sub => 1,
parsub => 1,
scp_get => 2,
scp_put => 2,
rsync_get => 2,
rsync_put => 2 );
my %push_max_args = ( here => 1,
goto => 1,
stop => 0 );
sub push {
my $self = shift;
my $selector = shift;
my $action = shift;
my $in_state = $self->{in_state};
if (ref $action eq 'CODE') {
unshift @_, $action;
$action = 'sub';
}
my $alias = $push_action_alias{$action};
$action = $alias if defined $alias;
$action =~ /^(?:command|(?:(?:rsync|scp)_(?:get|put))|join|sub|parsub|here|stop|goto|_notify)$/
or croak "bad action '$action'";
my %opts = (($action ne 'sub' and ref $_[0] eq 'HASH') ? %{shift()} : ());
%opts and grep($action eq $_, qw(join here))
and croak "unsupported option(s) '" . join("', '", keys %opts) . "' in $action action";
my @labels = $self->_select_labels($selector);
my $max = $push_max_args{$action};
croak "too many parameters for action $action"
if (defined $max and $max < @_);
my $min = $push_min_args{$action};
croak "too few parameters for action $action"
if (defined $min and $min > @_);
if ($action eq 'join') {
my $notify_selector = shift @_;
my $join = { id => '#' . $self->{join_seq}++,
depends => {},
notify => [] };
my @depends = $self->push($notify_selector, _notify => {}, $join)
or do {
$join->_debug(join => "join $join->{id} does not depend on anything, ignoring!");
return ();
};
$join->{depends}{$_} = 1 for @depends;
for my $label (@labels) {
my $host = $self->{hosts}{$label};
push @{$host->{queue}}, [join => {}, $join];
$debug and _debug(api => "[$label] join $join->{id} queued");
$self->_set_host_state($label, 'ready')
if $in_state->{done}{$label};
}
}
else {
for my $label (@labels) {
my $host = $self->{hosts}{$label};
push @{$host->{queue}}, [$action, \%opts, @_];
$debug and _debug(api => "[$label] action $action queued");
$self->_set_host_state($label, 'ready')
if $in_state->{done}{$label};
}
}
@labels;
}
sub _audit_conns {
my $self = shift;
my $hosts = $self->{hosts};
my $num = 0;
$num++ for grep $_->{ssh}, values %$hosts;
$debug and _debug(conns => "audit_conns counted: $num, saved: $self->{num_conns}");
$num == $self->{num_conns}
or die "internal error: wrong number of connections, counted: $num, saved: $self->{num_conns}";
my $in_state = $self->{in_state};
for my $state (keys %$in_state) {
my $num = 0;
$num++ for grep $hosts->{$_}{ssh}, keys %{$in_state->{$state}};
my $total = keys %{$in_state->{$state}};
print STDERR "conns in state $state: $num of $total\n";
}
}
sub _hash_chain_get {
my $name = shift;
for (@_) {
if (defined $_) {
my $v = $_->{$name};
return $v if defined $v;
}
}
undef;
}
sub _at_error {
my ($self, $label, $error) = @_;
my $host = $self->{hosts}{$label};
my $task = delete $host->{current_task};
my $queue = $host->{queue};
$debug and _debug(error => "_at_error label: $label, error: $error");
my $opts;
$opts = $task->[1] if $task;
my $on_error;
if ($error == OSSH_MASTER_FAILED) {
if ($host->{state} eq 'connecting') {
# task is not set in state connecting!
$task and die "internal error: task is defined in state connecting";
$opts = $queue->[0][1] if @$queue;
}
my $max_reconnections = _hash_chain_get(reconnections => $opts, $host, $self) || 0;
my $reconnections = $host->{current_task_reconnections}++ || 0;
$debug and _debug(error => "[$label] reconnection: $reconnections, max: $max_reconnections");
if ($reconnections < $max_reconnections) {
$debug and _debug(error => "[$label] will reconnect!");
$on_error = OSSH_ON_ERROR_RETRY;
}
}
$on_error ||= _hash_chain_get(on_error => $opts, $host, $self);
if (ref $on_error eq 'CODE') {
if ($error == OSSH_JOIN_FAILED) {
$on_error = $on_error->($self, $label, $error);
}
else {
$on_error = $on_error->($self, $label, $error, $task);
}
}
$on_error = OSSH_ON_ERROR_ABORT if (not defined $on_error or
$error == OSSH_ABORTED);
$debug and _debug(error => "[$label] on_error (final): $on_error, error: $error (".($error+0).")");
if ($on_error == OSSH_ON_ERROR_RETRY) {
if ($error == OSSH_MASTER_FAILED) {
$self->_set_host_state($label, 'suspended');
$self->_disconnect_host($label);
$self->_set_host_state($label, 'ready');
}
elsif ($error == OSSH_GOTO_FAILED) {
# No way to retry after a GOTO error!
# That should probably croak, but that would leave unmanaged
# processes running
$on_error = OSSH_ON_ERROR_ABORT;
}
else {
unshift @$queue, $task;
}
return;
}
delete $host->{current_task_reconnections};
if ($on_error == OSSH_ON_ERROR_IGNORE) {
if ($error == OSSH_MASTER_FAILED) {
# stablishing a new connection failed, what we should do?
# currently we remove the current task from the queue and
# continue.
shift @$queue unless $task;
$self->_set_host_state($label, 'suspended');
$self->_disconnect_host($label);
$self->_set_host_state($label, 'ready');
}
else {
$self->_set_host_state($label, 'ready');
}
# else do nothing
}
else {
unless ($on_error == OSSH_ON_ERROR_DONE or
$on_error == OSSH_ON_ERROR_ABORT or
$on_error == OSSH_ON_ERROR_ABORT_ALL) {
carp "bad on_error code $on_error";
$on_error = OSSH_ON_ERROR_ABORT;
}
my $queue = $host->{queue};
my $failed = ($on_error != OSSH_ON_ERROR_DONE);
$debug and _debug(error => "[$label] dropping queue, ", scalar(@$queue), " jobs");
while (my $task = shift @$queue) {
my ($action, undef, $join) = @$task;
$debug and _debug(error => "[$label] remove action $action from queue");
$self->_join_notify($label, $join, $failed)
if $action eq '_notify';
}
$on_error == OSSH_ON_ERROR_ABORT_ALL
and $self->{abort_all} = 1;
$self->_set_host_state($label, 'done');
$self->_disconnect_host($label);
$host->{error} = $error;
}
}
sub _at_connect {
my ($self, $label) = @_;
my $host = $self->{hosts}{$label};
$debug and _debug(connect => "[$label] _connect, starting SSH connection");
$host->{ssh} and die "internal error: connecting host is already connected";
my $ssh = $host->{ssh} = Net::OpenSSH->new(expand_vars => 1,
%{$host->{opts}},
async => 1);
$ssh->set_var(LABEL => $label);
my $master_pid = $ssh->get_master_pid;
$host->{master_pid} = $master_pid;
$self->{ssh_master_by_pid}{$master_pid} = $label;
$self->{num_conns}++;
$self->_set_host_state($label, 'connecting');
if ($ssh->error) {
$self->_at_error($label, $ssh->error);
}
}
sub _at_connecting {
my ($self, $label) = @_;
my $host = $self->{hosts}{$label};
$debug and _debug(at => "[$label] at_connecting, waiting for master");
my $ssh = $host->{ssh};
if ($ssh->wait_for_master(1)) {
$debug and _debug(at => "[$label] at_connecting, master connected");
$self->_set_host_state($label, 'ready');
}
elsif ($ssh->error) {
$self->_at_error($label, $ssh->error);
}
}
sub _join_notify {
my ($self, $label, $join, $failed) = @_;
# use Data::Dumper;
# print STDERR Dumper $join;
delete $join->{depends}{$label}
or die "internal error: $join->{id} notified for non dependent label $label";
$debug and _debug(join => "removing dependent $label from join $join->{id}");
$join->{failed} = 1 if $failed;
if (not %{$join->{depends}}) {
$debug and _debug(join => "join $join->{id} done");
$join->{done} = 1;
my $failed = $join->{failed};
for my $label (@{$join->{notify}}) {
$debug and _debug(join => "notifying $label about join $join->{id} done");
$self->_set_host_state($label, $failed ? 'join_failed' : 'ready');
}
}
# print STDERR Dumper $join;
}
sub _num_workers {
my $in_state = shift->{in_state};
( keys(%{$in_state->{ready}}) +
keys(%{$in_state->{running}}) +
keys(%{$in_state->{connecting}}) );
}
sub _disconnect_host {
my ($self, $label) = @_;
my $host = $self->{hosts}{$label};
my $state = $host->{state};
$state =~ /^(?:waiting|suspended|done|connecting)$/
or die "internal error: disconnecting $label in state $state";
if ($host->{ssh}) {
$debug and _debug(connect => "[$label] disconnecting host");
my $master_pid = delete $host->{master_pid};
delete $self->{ssh_master_by_pid}{$master_pid}
if defined $master_pid;
undef $host->{ssh};
$self->{num_conns}--;
$self->_set_host_state($label, $state);
}
}
sub _disconnect_any_host {
my $self = shift;
my $connected = $self->{connected};
$debug and _debug(conns => "disconnect any host");
# $self->_audit_conns;
my $label;
for my $state (qw(suspended join_failed waiting)) {
# use Data::Dumper;
# print Dumper $connected;
$debug and _debug(conns => "looking for connected host in state $state");
($label) = each %{$connected->{$state}};
keys %{$connected->{$state}}; # reset iterator
last if defined $label;
}
$debug and _debug(conns => "[$label] disconnecting");
defined $label or die "internal error: unable to disconnect any host";
$self->_disconnect_host($label);
}
my @private_opts = qw(on_error or_goto reconnections);
sub _at_ready {
my ($self, $label) = @_;
if (my $max_workers = $self->{max_workers}) {
my $in_state = $self->{in_state};
my $num_workers = $self->_num_workers;
$debug and _debug(workers => "num workers: $num_workers, maximun: $max_workers");
if ($num_workers > $max_workers) {
$debug and _debug(workers => "[$label] suspending");
$self->_set_host_state($label, 'suspended');
return;
}
}
my $host = $self->{hosts}{$label};
$debug and _debug(at => "[$label] at_ready");
my $queue = $host->{queue};
if ($self->{abort_all}) {
$self->_at_error($label, OSSH_ABORTED);
return;
}
while (defined (my $task = shift @$queue)) {
my $action = shift @$task;
$debug and _debug(at => "[$label] at_ready, starting new action $action");
if ($action eq 'join') {
my (undef, $join) = @$task;
if ($join->{done}) {
$debug and _debug(join => "join[$join->{id}] is done");
if ($join->{failed}) {
$self->_at_error($label, OSSH_JOIN_FAILED);
return;
}
$debug and _debug(action => "[$label] join $join->{id} already done");
next;
}
CORE::push @{$join->{notify}}, $label;
$self->_set_host_state($label, 'waiting');
return;
}
elsif ($action eq 'here') {
next;
}
elsif ($action eq 'stop') {
$self->_skip($label, 'END');
next;
}
elsif ($action eq 'goto') {
my (undef, $target) = @$task;
$self->_skip($label, $target);
next;
}
elsif ($action eq '_notify') {
my (undef, $join) = @$task;
$self->_join_notify($label, $join);
next;
}
elsif ($action eq 'sub') {
# use Data::Dumper;
# _debug (action => Dumper(@$task));
shift @$task;
my $sub = shift @$task;
$debug and _debug(action => "[$label] calling sub $sub");
$sub->($self, $label, @$task);
next;
}
else {
my $ssh = $host->{ssh};
unless ($action eq 'parsub' and $task->[0]{no_ssh}) {
unless ($ssh) {
# unshift the task we have just removed and connect first:
unshift @$task, $action;
unshift @$queue, $task;
if (my $max_conns = $self->{max_conns}) {
$self->_disconnect_any_host() if $self->{num_conns} >= $max_conns;
}
$debug and _debug(at => "[$label] host is not connected, connecting...");
$self->_at_connect($label);
return;
}
if (my $error = $ssh->error) {
$self->_at_error($label, $error);
return;
}
}
$host->{current_task} = [$action, @$task];
my %opts = %{shift @$task};
delete @opts{@private_opts};
my $method = $self->can("_start_$action")
or die "internal error: method _start_$action not found";
my $pid = $method->($self, $label, \%opts, @$task);
$debug and _debug(action => "[$label] action pid: ", $pid);
unless (defined $pid) {
my $error = (($ssh && $ssh->error) ||
dualvar(($action eq 'parsub'
? "Unable to fork parsub"
: "Action $action failed to start"), OSSH_SLAVE_FAILED));
$self->_at_error($label, $error);
return;
}
$self->{host_by_pid}{$pid} = $label;
$self->_set_host_state($label, 'running');
return;
}
}
$debug and _debug(at => "[$label] at_ready, queue_is_empty, we are done!");
$self->_set_host_state($label, 'done');
$self->_disconnect_host($label);
}
sub _start_parsub {
my $self = shift;
my $label = shift;
my $opts = shift;
my $sub = shift;
my $ssh = $self->{hosts}{$label}{ssh};
$debug and _debug(action => "[$label] start parsub action [@_]");
my $pid = fork;
unless ($pid) {
defined $pid or return;
eval { $sub->($label, $ssh, @_) };
$@ and $debug and _debug(error => "slave died on parsub: $@");
POSIX::_exit($@ ? 1 : 0);
}
$pid;
}
sub _start_command {
my $self = shift;
my $label = shift;
my $opts = shift;
my $ssh = $self->{hosts}{$label}{ssh};
$debug and _debug(action => "[$label] start command action [@_]");
$ssh->spawn($opts, @_);
}
sub _start_scp_get {
my $self = shift;
my $label = shift;
my $opts = shift;
my $ssh = $self->{hosts}{$label}{ssh};
$debug and _debug(action => "[$label] start scp_get action");
$opts->{async} = 1;
$ssh->scp_get($opts, @_);
}
sub _start_scp_put {
my $self = shift;
my $label = shift;
my $opts = shift;
my $ssh = $self->{hosts}{$label}{ssh};
$debug and _debug(action => "[$label] start scp_put action");
$opts->{async} = 1;
$ssh->scp_put($opts, @_);
}
sub _start_rsync_get {
my $self = shift;
my $label = shift;
my $opts = shift;
my $ssh = $self->{hosts}{$label}{ssh};
$debug and _debug(action => "[$label] start rsync_get action");
$opts->{async} = 1;
$ssh->rsync_get($opts, @_);
}
sub _start_rsync_put {
my $self = shift;
my $label = shift;
my $opts = shift;
my $ssh = $self->{hosts}{$label}{ssh};
$debug and _debug(action => "[$label] start rsync_put action");
$opts->{async} = 1;
$ssh->rsync_put($opts, @_);
}
# FIXME: dead code?
sub _start_join {
my $self = shift;
my $label = shift;
warn "internal mismatch: this shouldn't be happening!";
}
sub _skip {
my ($self, $label, $target) = @_;
$debug and _debug(action => "skipping until $target");
my $host = $self->{hosts}{$label};
my $queue = $host->{queue};
my ($ix, $task);
for ($ix = 0; defined($task = $queue->[$ix]); $ix++) {
last if ($task->[0] eq 'here' and $task->[2] eq $target);
}
if ($task or $target eq 'END') {
for (1..$ix) {
my $task = shift @$queue;
$self->_join_notify($label, $task->[2])
if $task->[0] eq '_notify';
}
return;
}
$debug and _debug(action => "here label $target not found");
$self->_at_error($label, OSSH_GOTO_FAILED);
}
sub _finish_task {
my ($self, $pid) = @_;
my $label = delete $self->{host_by_pid}{$pid};
if (defined $label) {
$debug and _debug(action => "[$label] action finished pid: $pid, rc: $?");
my $host = $self->{hosts}{$label};
my $or_goto;
if ($?) {
my ($action) = @{$host->{current_task}};
my $rc = ($? >> 8);
my $ssh = $host->{ssh} or die "internal error: $label is not connected";
my $error = $ssh->error;
$or_goto = $host->{current_task}[1]{or_goto} unless ($error or $rc == 255);
if (defined $or_goto) {
$debug and _debug(action => "[$label] skipping to $or_goto with rc = $rc");
}
else {
$error ||= dualvar(OSSH_SLAVE_FAILED,
"child exited with non-zero return code ($rc)");
$self->_at_error($label, $error);
return
}
}
$self->_set_host_state($label, 'ready');
$self->_skip($label, $or_goto) if defined $or_goto;
delete $host->{current_task};
delete $host->{current_task_reconnections};
}
else {
my $label = delete $self->{ssh_master_by_pid}{$pid};
defined $label or carp "spurious child exit (pid: $pid)";
$debug and _debug(action => "[$label] master ssh exited");
my $host = $self->{hosts}{$label};
my $ssh = $host->{ssh}
or die ("internal error: master ssh process exited but ".
"there is no ssh object associated to host $label");
$ssh->master_exited;
my $state = $host->{state};
# do error handler later...
}
}
sub _wait_for_jobs {
my ($self, $time) = @_;
my $dontwait = ($time == 0);
$debug and _debug(at => "_wait_for_jobs time: $time");
# This loop is here because we want to call waitpit before and
# after the select. If we find some child has exited in the first
# round we don't call select at all and return immediately
while (1) {
if (%{$self->{in_state}{running}}) {
$debug and _debug(at => "_wait_for_jobs reaping children");
while (1) {
my $pid = waitpid(-1, WNOHANG);
last if $pid <= 0;
$debug and _debug(action => "waitpid caught pid: $pid, rc: $?");
$dontwait = 1;
$self->_finish_task($pid);
}
}
$dontwait and return 1;
$debug and _debug(at => "_wait_for_jobs calling select");
{
# This is a hack to make select finish as soon as we get a
# CHLD signal.
local $SIG{CHLD} = sub {};
select(undef, undef, undef, $time);
}
$dontwait = 1;
}
}
sub _clean_errors {
my $self = shift;
delete $_->{error} for values %{$self->{hosts}};
}
sub run {
my ($self, $time) = @_;
$self->_clean_errors;
my $hosts = $self->{hosts};
my $max_workers = $self->{max_workers};
my ($connecting, $ready, $running, $waiting, $suspended, $join_failed, $done) =
@{$self->{in_state}}{qw(connecting ready running waiting suspended join_failed done)};
my $connected_suspended = $self->{connected}{suspended};
while (1) {
# use Data::Dumper;
# print STDERR Dumper $self;
$debug and _debug(api => "run: iterating...");
$debug and _debug(at => "run: hosts at connecting: ", scalar(keys %$connecting));
$self->_at_connecting($_) for keys %$connecting;
$debug and _debug(at => "run: hosts at ready: ", scalar(keys %$ready));
# $self->_audit_conns;
$self->_at_ready($_) for keys %$ready;
# $self->_audit_conns;
$debug and _debug(at => 'run: hosts at join_failed: ', scalar(keys %$join_failed));
$self->_at_error($_, OSSH_JOIN_FAILED) for keys %$join_failed;
if ($max_workers) {
$debug and _debug(at => "run: hosts at suspended:", scalar(keys %$suspended));
if (%$suspended) {
my $awake = $max_workers - $self->_num_workers;
my @labels;
for my $hash ($connected_suspended, $suspended) {
while ($awake > 0) {
my ($label) = each %$hash or last;
CORE::push @labels, $label;
$awake--;
}
for my $label (@labels) {
$debug and _debug(workers => "[$label] awaking");
$self->_set_host_state($label, 'ready');
}
keys %$hash; # do we really need to reset the each iterator?
}
}
}
$debug and _debug(at => "run: hosts at waiting: ", scalar(keys %$waiting));
$debug and _debug(at => "run: hosts at running: ", scalar(keys %$running));
$debug and _debug(at => "run: hosts at done: ", scalar(keys %$done), " of ", scalar(keys %$hosts));
last if keys(%$hosts) == keys(%$done);
my $time = ( %$ready ? 0 :
%$connecting ? 0.3 :
5.0 );
$self->_wait_for_jobs($time);
}
delete $self->{abort_all};
my $error;
for my $label (sort keys %$hosts) {
$hosts->{$label}{error} and $error = 1;
$debug and _debug(error => "[$label] error: ", $hosts->{$label}{error});
}
!$error;
}
sub get_error {
my ($self, $label) = @_;
my $host = $self->{hosts}{$label}
or croak "no such host $label has been added";
$host->{error}
}
sub get_errors {
my $self = shift;
if (wantarray) {
return map {
my $error = $self->get_error($_);
defined $error ? ($_ => $error) : ()
} sort keys %{$self->{hosts}}
}
else {
return grep defined($self->get_error($_)), keys %{$self->{hosts}}
}
}
1;
__END__
=head1 NAME
Net::OpenSSH::Parallel - Run SSH jobs in parallel
=head1 SYNOPSIS
use Net::OpenSSH::Parallel;
my $pssh = Net::OpenSSH::Parallel->new();
$pssh->add_host($_) for @hosts;
$pssh->push('*', scp_put => '/local/file/path', '/remote/file/path');
$pssh->push('*', command => 'gurummm',
'/remote/file/path', '/tmp/output');
$pssh->push($special_host, command => 'prumprum', '/tmp/output');
$pssh->push('*', scp_get => '/tmp/output', 'logs/%HOST%/output');
$pssh->run;
=head1 DESCRIPTION
Run this here, that there, etc.
C<Net::OpenSSH::Parallel> is an scheduler that can run commands in
parallel in a set of hosts through SSH. It tries to find a compromise
between being simple to use, efficient and covering a good part of the
problem space of parallel process execution via SSH.
Obviously, it is build on top of L<Net::OpenSSH>!
Common usage of the module is as follows:
=over
=item *
create a C<Net::OpenSSH::Parallel> object
=item *
register the hosts where you want to run commands with the
L</add_host> method
=item *
queue the actions you want to run (commands, file copy operations,
etc.) using the L</push> method.
=item *
call the L</run> method and let the parallel scheduler take care of
everything!
=back
=head2 Labelling hosts
Every host is identified by an unique label that is given when the
host is registered into the parallel scheduler. Usually, the host
name is used also as the label, but this is not required by the
module.
The rationale behind using labels is that a hostname does not
necessarily identify unique "remote processors" (for instance,
sometimes your logical "remote processors" may be user accounts
distributed over a set of hosts: C<foo1@bar1>, C<foo2@bar1>,
C<foo3@bar2>, ...; a set of hosts that are accesible behind an unique
IP, listening in different ports; etc.)
=head2 Selecting hosts
Several of the methods of this module (well, currently, just C<push>)
accept a selector string to determine which of the registered hosts
should be affected by the operation.
For instance, in...
$pssh->push('*', command => 'ls')
the first argument is the selector. The one used here, C<*>, selects
all the registered hosts.
Other possible selectors are:
'bar*' # selects everything beginning by 'bar'
'foo1,foo3,foo6' # selects the hosts of the given names
'bar*,foo1,foo3,foo6' # both
'*doz*' # everything containing 'doz'
I<Note: I am still considering how the selector mini-language should
be, don't hesitate to send your suggestions!>
=head2 Local resource usage
When the number of hosts managed by the scheduler is too high, the
local node can become overloaded.
Roughly, every SSH connection requires two local C<ssh> processes
(one to run the SSH connection and another one to launch the remote
command) that results in around 5MB of RAM usage per host.
CPU usage varies greatly depending on the tasks carried out. The most
expensive are short remote tasks (because of the local process
creation and destruction overhead) and tasks that transfer big
ammounts of data through SSH (because of the encryption going on).
In practice, CPU usage doesn't matter too much (mostly because the OS
would be able to manage it but also because there is not too many
things we can do to reduce it) and usually it is RAM about what we
should be more concerned.
The module accepts two parameters to limit resource usage:
=over
=item * C<workers>
is the maximun number of remote commands that can be running
concurrently.
=item * C<connections>
is the maximum number of SSH connections that can be active
concurrently.
=back
In practice, limiting the maximum number of connections indirectly
limits RAM usage and limiting the the maximum number of workers
indirectly limits CPU usage.
The module requires the maximum number of connections to be at least
equal or bigger than the maximun number of workers, and it is
recomended that C<maximum_connections E<gt>= 2 * maximum_workers>
(otherwise the scheduler will not be able to reuse connections
efficiently).
You will have to experiment to find out which combinations give the
best results in your particular scenarios.
Also, for small sets of hosts you can just let these parameters
unlimited.
=head2 Variable expansion
This module activates L<Net::OpenSSH> L<variable
expansion|Net::OpenSSH/Variable expansion> by default. That way, it is
possible to easily customize the actions executed on every host in
base to some of its properties.
For instance:
$pssh->push('*', scp_get => "/var/log/messages", "messages.%HOST%");
copies the log files appending the name of the remote hosts to the
local file names.
The variables C<HOST>, C<USER>, C<PORT> and C<LABEL> are predefined.
=head2 Error handling
When something goes wrong (for instance, some host is unreachable,
some connection dies, some command fails, etc.) the module can handle
the error in several predefined ways as follows:
=head3 Error policies
To set the error handling police, L</new>, L</add_host> and L</push>
methods support and optional C<on_error> argument that can take the
following values (these constants are available from
L<Net::OpenSSH::Parallel::Constants>):
=over 4
=item OSSH_ON_ERROR_IGNORE
Ignores the error and continues executing tasks in the host queue as
it had never happened.
=item OSSH_ON_ERROR_ABORT
Aborts the processing on the corresponding host. The error will be
propagated to other hosts joining it at any later point once the join
is reached.
In other words, this police aborts the queued jobs for this host
and any other that has a dependency on it.
=item OSSH_ON_ERROR_DONE
Similar to C<OSSH_ON_ERROR_ABORT> but will not propagate errors to
other hosts via joins.
=item OSSH_ON_ERROR_ABORT_ALL
Causes all the host queues to be aborted as soon as possible (and that
usually means after currently running actions end).
=item OSSH_ON_ERROR_REPEAT
The module will try to perform the current task again and again until
it succeeds. This police can lead to an infinite loop and so its
direct usage is discouraged (but see the following point about setting
the policy dynamically).
=back
The default policy is C<OSSH_ON_ERROR_ABORT>.
=head3 Setting the policy dynamically
When a subroutine reference is used as the policy instead of the any of the
constants previously described, the given subroutine will be called on
error conditions as follows:
$on_error->($pssh, $label, $error, $task)
C<$pssh> is a reference to the C<Net::OpenSSH::Parallel> object,
C<$label> is the label associated to the host where the error
happened. C<$error> is the error type as defined in
L<Net::OpenSSH::Parallel::Constants> and $task is a reference to the
task that was being carried out.
The return value of the subroutine must be one of the described
constants and the corresponding policy will be applied.
=head3 Retrying connection errors
If the module fails when trying to stablish a new SSH connection or
when an existing connection dies unexpectedly, the option
C<reconnections> can be used to instruct the module to retry the
connection until it succeds or the given maximun is reached.
C<reconnections> is accepted by both the L</new> and L</add_host>
methods.
Example:
$pssh->add_host('foo', reconnections => 3);
Note that the reconnections maximum is not per host but per queued
task.
=head2 API
These are the available methods:
=over
=item $pssh = Net::OpenSSH::Parallel->new(%opts)
creates a new object.
The accepted options are:
=over
=item workers => $maximum_workers
sets the maximum number of operations that can be carried out in
parallel (see L</Local resource usage>).
=item connections => $maximum_connections
sets the maximum number of SSH connections that can be stablished
simultaneously (see L</Local resource usage>).
$maximum_connections must be equal or bigger than $maximum_workers
=item reconnections => $maximum_reconnections
when connecting to some host fails, this argument tells the module the
maximum number of additional connection atemps that it should perform
before giving up. The default value is zero.
See also L</Retrying connection errors>.
=item on_error => $policy
Sets the error handling policy (see L</Error handling>).
=back
=item $pssh->add_host($label, %opts)
=item $pssh->add_host($label, $host, %opts)
X<add_host>registers a new host into the C<$pssh> object.
C<$label> is the name used to refer to the registered host afterwards.
When the hostname argument is ommited, the label is used also as the
hostname.
The accepted options are:
=over
=item on_error => $policy
Sets the error handling policy (see L</Error handling>).
=item reconnections => $maximum_reconnections
See L</Retrying connection errors>.
=back
Any additional option will be passed verbatim to the L<Net::OpenSSH>
constructor later. For instance:
$pssh->add_host($host, user => $user, password => $password);
=item $pssh->push($selector, $action, \%opts, @action_args)
=item $pssh->push($selector, $action, @action_args)
pushes a new action into the queues selected by C<$selector>.
The supported actions are:
=over
=item command => @cmd
queue the given shell command on the selected hosts.
Example:
$self->push('*', 'command'
{ stdout_fh => $find_fh, stderr_to_stdout => 1 },
'find', '/my/dir');
=item scp_get => @remote, $local
=item scp_put => @local, $remote
These methods queue an SCP remote file copy operation in the selected
hosts.
=item rsync_get => @remote, $local
=item rsync_put => @local, $remote
These methods queue an rsync remote file copy operation in the
selected hosts.
=item sub => sub { ... }, @extra_args
=item sub { ... }, @extra_args
Queues a call to a perl subroutine that will be executed locally.
Note that subroutines are executed synchronously in the same process,
so no other task will be scheduled while they are running.
The sub is called as
$sub->($pssh, $label, @extra_args)
where C<$pssh> is the current Net::OpenSSH::Parallel object.
=item parsub => sub { ... }, @extra_args
Queues a call to a perl subroutine that will be executed locally on a
forked process.
The sub is called as
$sub->($label, $ssh, @extra_args)
Where C<$ssh> is an L<Net::OpenSSH> object that can be used to
interact with the remote machine.
Note that the interface is different to that of the C<sub> action.
An example of usage:
sub sudo_install {
my ($label, $ssh, @pkgs) = @_;
my ($pty) = $ssh->open2pty('sudo', 'apt-get', 'install', @pkgs);
my $expect = Expect->init($pty);
$expect->raw_pty(1);
$expect->expect($timeout, ":");
$expect->send("$passwd\n");
$expect->expect($timeout, "\n");
$expect->raw_pty(0);
while(<$expect>) { print };
close $expect;
}
$pssh->push('*', parsub => \&sudo_install, 'scummvm');
If the subroutine dies or calls C<_exit> with a non zero return code,
the error handling code will be triggered (see L</"Error handling">).
The C<parsub> action accepts the additional option C<no_ssh>
indicating that the C<$ssh> object is not going to be used. For
instance:
$pssh->push('*', parsub => { no_ssh => 1 },
sub {
my $label = shift;
{ exec "gzip", "/tmp/file-$label" };
die "exec failed: $!";
});
That can make the script faster when the maximum number of
simultaneous connections is limited. See L<Local resource usage>.
=item join => $selector
Joins allow to synchronize jobs between different servers.
For instance:
$ssh->push('server_B', scp_get => '/tmp/foo', 'foo');
$ssh->push('server_A', join => 'server_B');
$ssh->push('server_A', scp_put => 'foo', '/tmp/foo');
The join makes server_A to wait for the C<scp_get> operation queued in
server_B to finish before proceeding with the C<scp_put>.
In general the join will make the selected servers wait for any task
queued on the servers matched by C<$selector> to finish before
proceeding with the next queued tasks.
One common usage is to synchronize all servers at some point:
$ssh->push('*', join => '*');
By default, errors are propagated at joins. For instance, in the
example above, if the scp_get operation queued on server_B failed, it
would abort any further operation queued on server_B and any further
operation queued after the join in server_A. See also L</Error
handling>.
=item here => $tag
Push a tag in the stack that can be used as a target for goto
operations.
=item goto => $target
Jumps forward until the given C<here> tag is reached.
Joins to other hosts queues will be ignored, and joins from other
queues to this one will be succesfully fulfilled. For instance:
$pssh->add_host(A => ...);
$pssh->add_host(B => ...);
$pssh->push('*', cmd => 'echo "hello from %HOST"');
$pssh->push('A', goto => 'there');
$pssh->push('A', join => 'B'); # ignored by A on goto
$pssh->push('B', join => 'A'); # fulfilled by A on goto
$pssh->push('*', cmd => 'echo "hello from %HOST% again"');
$pssh->push('*', here => 'there');
$pssh->push('*', cmd => 'echo "bye bye from %HOST%");
Note that it is not possible to jump backguards.
There is an special target C<END> that can be used to jump to the end
of the queue.
=item stop
Discards any additional operations queued. Any pending joins will be
successfully fulfilled.
It is equivalent to
$pssh->push('*', goto => 'END');
=back
When given, C<%opts> can contain the following options:
=over 4
=item on_error => $fail_mode
=item on_error => sub { ... }
See L</Error handling>.
=item or_goto => $tag
Supported for C<command>, C<scp_get>, C<scp_put>, C<rsync_get> and
C<rsync_put>, when the command, scp or rsync operation fails a goto to
the given target is performed.
For instance:
$pssh->all(command => { or_goto => 'no_file' },
"test -f /etc/foo");
$pssh->all(scp_get => "/etc/foo", "/tmp/foo-%LABEL%");
$pssh->all(here => "no_file");
Failures related to SSH errors do not trigger the goto but the error
handling code.
=item timeout => $seconds
not implemented yet!
=item on_done => sub { ... }
not implemented yet!
=back
Any other option will be passed to the corresponding L<Net::OpenSSH>
method (L<spawn|Net::OpenSSH/spawn>, L<scp_put|Net::OpenSSH/scp_put>,
etc.).
=item $pssh->all($action => @args)
=item $pssh->all($action => \%opts, @args)
Shortcut for...
$pssh->push('*', $action, \%opts, @args);
=item $pssh->run
Runs the queued operations.
It returns a true value on success and false otherwise.
=item $pssh->get_error($label)
Returns the last error associated to the host of the given label.
=item $pssh->get_errors
In list context returns a list of pairs C<$label =E<gt> $error> for the failed queues.
In scalar context returns the number of failed queues.
=back
=head1 FAQ - Frequently Asked Questions
=over 4
=item Running remote commands with sudo
B<Q>: I need to run the remote commands with sudo that asks for a
password. How can I do it?
B<A>: First read the answer given to a similar question on
L<Net::OpenSSH> FAQ.
The problem is that Net::OpenSSH::Parallel methods do not support the
<stdin_data> option, so you will have to use an external file.
$pssh->push('*', cmd => { stdin_file => $passwd_file },
'sudo', '-Skp', '', '--', @cmd);
One trick you can use if you only have one password is to use the
C<DATA> file handle:
$pssh->push('*', cmd => { stdin_fh => \*DATA},
'sudo', '-Skp', '', '--', @cmd);
...
# and at the end of your script
__DATA__
this-is-my-remote-password-for-sudo
Or you can also use the C<parsub> action:
my %sudo_passwords = (host1 => "foo", ...);
sub sudo {
my ($label, $ssh, @cmd) = @_;
$ssh->system({stdin_data => "$sudo_passwords{$label}\n"},
'sudo', '-Skp', '', '--', @cmd);
}
$pssh->push('*', parsub => \&sudo, @cmd);
=back
=head1 TODO
=over
=item * run N processes per host concurrently
allow running more than one process per remote server concurrently
=item * delay before reconnect
when connecting fails, do not try to reconnect inmediately but after
some predefined period
=item * rationalize debugging
currently it is a mess
=item * add loggin support
log the operations performed in a given file
=item * stdio redirection
add support for better handling of the Net::OpenSSH stdio redirection
facilities
=item * configurable valid return codes
Non zero exit code is not always an error.
=back
=head1 BUGS AND SUPPORT
This module should be considered beta quality, everything seems to
work but it may yet contain critical bugs.
If you find any, report it via L<http://rt.cpan.org> or by email (to
sfandino@yahoo.com), please.
Feedback and comments are also welcome!
The 'sub' and 'parsub' features should be considered experimental and
its API or behaviour could be changed in future versions of the
module.
=head2 Reporting bugs
In order to report a bug, write a minimal program that triggers
it and place the following line at the beggining:
$Net::OpenSSH::Parallel::debug = -1;
Then, send me (via rt or email) the debugging output you get when you
run it. Include also the source code of the script, a description of
what is going wrong and the details of your OS and the versions of
Perl, C<Net::OpenSSH> and C<Net::OpenSSH::Parallel> you are using.
=head2 Development version
The source code for this module is hosted at GitHub:
L<http://github.com/salva/p5-Net-OpenSSH-Parallel>.
=head2 Commercial support
Commercial support, professional services and custom software
development around this module are available through my current
company. Drop me an email with a rough description of your
requirements and we will get back to you ASAP.
=head2 My wishlist
If you like this module and you're feeling generous, take a look at my
Amazon Wish List: L<http://amzn.com/w/1WU1P6IR5QZ42>
Also consider contributing to the OpenSSH project this module builds
upon: L<http://www.openssh.org/donations.html>.
=head1 SEE ALSO
L<Net::OpenSSH> is used to manage the SSH connections to the remote
hosts.
L<SSH::Batch> has a similar focus as this module. In my opinion it is
simpler to use but rather more limited.
L<GRID::Machine> allows to run perl code distributed in a cluster via
SSH.
If your application requires orchestating workflows more complex than
those supported by L<Net::OpenSSH::Parallel>, you should probably
consider some L<POE> or L<AnyEvent> based solution (check
L<POE::Component::OpenSSH>).
L<App::MrShell> is another module allowing to run the same command in
several host in parallel.
Some people find easier to use L<Net::OpenSSH> combined with
L<Parallel::ForkManager>, L<threads> or L<Coro>.
L<Net::SSH::Mechanize> is another framework written on top of
L<AnyEvent> that allows to run remote commands through SSH in
parallel.
=head1 COPYRIGHT AND LICENSE
Copyright E<copy> 2009-2012 by Salvador FandiE<ntilde>o
(sfandino@yahoo.com).
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.10.0 or,
at your option, any later version of Perl 5 you may have available.
=cut
|