/usr/share/doc/swift-doc/html/ring.html is in swift-doc 1.13.1-0ubuntu1.
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 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Partitioned Consistent Hash Ring — swift 1.13.1 documentation</title>
<link rel="stylesheet" href="_static/sphinxdoc.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<link rel="stylesheet" href="_static/tweaks.css" type="text/css" />
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: './',
VERSION: '1.13.1',
COLLAPSE_INDEX: false,
FILE_SUFFIX: '.html',
HAS_SOURCE: true
};
</script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<link rel="top" title="swift 1.13.1 documentation" href="index.html" />
<link rel="next" title="Proxy" href="proxy.html" />
<link rel="prev" title="Logs" href="logs.html" />
</head>
<body>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="proxy.html" title="Proxy"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="logs.html" title="Logs"
accesskey="P">previous</a> |</li>
<li><a href="index.html">swift 1.13.1 documentation</a> »</li>
</ul>
</div>
<div class="sphinxsidebar">
<div class="sphinxsidebarwrapper">
<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Partitioned Consistent Hash Ring</a><ul>
<li><a class="reference internal" href="#ring">Ring</a></li>
<li><a class="reference internal" href="#module-swift.common.ring.builder">Ring Builder</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="logs.html"
title="previous chapter">Logs</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="proxy.html"
title="next chapter">Proxy</a></p>
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="_sources/ring.txt"
rel="nofollow">Show Source</a></li>
</ul>
<div id="searchbox" style="display: none">
<h3>Quick search</h3>
<form class="search" action="search.html" method="get">
<input type="text" name="q" size="18" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
<p class="searchtip" style="font-size: 90%">
Enter search terms or a module, class or function name.
</p>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
</div>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body">
<div class="section" id="partitioned-consistent-hash-ring">
<span id="consistent-hashing-ring"></span><h1>Partitioned Consistent Hash Ring<a class="headerlink" href="#partitioned-consistent-hash-ring" title="Permalink to this headline">¶</a></h1>
<div class="section" id="ring">
<span id="id1"></span><h2>Ring<a class="headerlink" href="#ring" title="Permalink to this headline">¶</a></h2>
<span class="target" id="module-swift.common.ring.ring"></span><dl class="class">
<dt id="swift.common.ring.ring.Ring">
<em class="property">class </em><tt class="descclassname">swift.common.ring.ring.</tt><tt class="descname">Ring</tt><big>(</big><em>serialized_path</em>, <em>reload_time=15</em>, <em>ring_name=None</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.Ring" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">object</span></tt></p>
<p>Partitioned consistent hashing ring.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>serialized_path</strong> – path to serialized RingData instance</li>
<li><strong>reload_time</strong> – time interval in seconds to check for a ring change</li>
</ul>
</td>
</tr>
</tbody>
</table>
<dl class="attribute">
<dt id="swift.common.ring.ring.Ring.devs">
<tt class="descname">devs</tt><a class="headerlink" href="#swift.common.ring.ring.Ring.devs" title="Permalink to this definition">¶</a></dt>
<dd><p>devices in the ring</p>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.Ring.get_more_nodes">
<tt class="descname">get_more_nodes</tt><big>(</big><em>part</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.Ring.get_more_nodes" title="Permalink to this definition">¶</a></dt>
<dd><p>Generator to get extra nodes for a partition for hinted handoff.</p>
<p>The handoff nodes will try to be in zones other than the
primary zones, will take into account the device weights, and
will usually keep the same sequences of handoffs even with
ring changes.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>part</strong> – partition to get handoff nodes for</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">generator of node dicts</td>
</tr>
</tbody>
</table>
<p>See <a class="reference internal" href="#swift.common.ring.ring.Ring.get_nodes" title="swift.common.ring.ring.Ring.get_nodes"><tt class="xref py py-func docutils literal"><span class="pre">get_nodes()</span></tt></a> for a description of the node dicts.</p>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.Ring.get_nodes">
<tt class="descname">get_nodes</tt><big>(</big><em>account</em>, <em>container=None</em>, <em>obj=None</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.Ring.get_nodes" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the partition and nodes for an account/container/object.
If a node is responsible for more than one replica, it will
only appear in the output once.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>account</strong> – account name</li>
<li><strong>container</strong> – container name</li>
<li><strong>obj</strong> – object name</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last">a tuple of (partition, list of node dicts)</p>
</td>
</tr>
</tbody>
</table>
<p>Each node dict will have at least the following keys:</p>
<table border="1" class="docutils">
<colgroup>
<col width="9%" />
<col width="91%" />
</colgroup>
<tbody valign="top">
<tr class="row-odd"><td>id</td>
<td>unique integer identifier amongst devices</td>
</tr>
<tr class="row-even"><td>weight</td>
<td>a float of the relative weight of this device as compared to
others; this indicates how many partitions the builder will try
to assign to this device</td>
</tr>
<tr class="row-odd"><td>zone</td>
<td>integer indicating which zone the device is in; a given
partition will not be assigned to multiple devices within the
same zone</td>
</tr>
<tr class="row-even"><td>ip</td>
<td>the ip address of the device</td>
</tr>
<tr class="row-odd"><td>port</td>
<td>the tcp port of the device</td>
</tr>
<tr class="row-even"><td>device</td>
<td>the device’s name on disk (sdb1, for example)</td>
</tr>
<tr class="row-odd"><td>meta</td>
<td>general use ‘extra’ field; for example: the online date, the
hardware description</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.Ring.get_part">
<tt class="descname">get_part</tt><big>(</big><em>account</em>, <em>container=None</em>, <em>obj=None</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.Ring.get_part" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the partition for an account/container/object.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>account</strong> – account name</li>
<li><strong>container</strong> – container name</li>
<li><strong>obj</strong> – object name</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last">the partition number</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.Ring.get_part_nodes">
<tt class="descname">get_part_nodes</tt><big>(</big><em>part</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.Ring.get_part_nodes" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the nodes that are responsible for the partition. If one
node is responsible for more than one replica of the same
partition, it will only appear in the output once.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>part</strong> – partition to get nodes for</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">list of node dicts</td>
</tr>
</tbody>
</table>
<p>See <a class="reference internal" href="#swift.common.ring.ring.Ring.get_nodes" title="swift.common.ring.ring.Ring.get_nodes"><tt class="xref py py-func docutils literal"><span class="pre">get_nodes()</span></tt></a> for a description of the node dicts.</p>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.Ring.has_changed">
<tt class="descname">has_changed</tt><big>(</big><big>)</big><a class="headerlink" href="#swift.common.ring.ring.Ring.has_changed" title="Permalink to this definition">¶</a></dt>
<dd><p>Check to see if the ring on disk is different than the current one in
memory.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body">True if the ring on disk has changed, False otherwise</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="attribute">
<dt id="swift.common.ring.ring.Ring.partition_count">
<tt class="descname">partition_count</tt><a class="headerlink" href="#swift.common.ring.ring.Ring.partition_count" title="Permalink to this definition">¶</a></dt>
<dd><p>Number of partitions in the ring.</p>
</dd></dl>
<dl class="attribute">
<dt id="swift.common.ring.ring.Ring.replica_count">
<tt class="descname">replica_count</tt><a class="headerlink" href="#swift.common.ring.ring.Ring.replica_count" title="Permalink to this definition">¶</a></dt>
<dd><p>Number of replicas (full or partial) used in the ring.</p>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="swift.common.ring.ring.RingData">
<em class="property">class </em><tt class="descclassname">swift.common.ring.ring.</tt><tt class="descname">RingData</tt><big>(</big><em>replica2part2dev_id</em>, <em>devs</em>, <em>part_shift</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.RingData" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">object</span></tt></p>
<p>Partitioned consistent hashing ring data (used for serialization).</p>
<dl class="classmethod">
<dt id="swift.common.ring.ring.RingData.deserialize_v1">
<em class="property">classmethod </em><tt class="descname">deserialize_v1</tt><big>(</big><em>gz_file</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.RingData.deserialize_v1" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="classmethod">
<dt id="swift.common.ring.ring.RingData.load">
<em class="property">classmethod </em><tt class="descname">load</tt><big>(</big><em>filename</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.RingData.load" title="Permalink to this definition">¶</a></dt>
<dd><p>Load ring data from a file.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>filename</strong> – Path to a file serialized by the save() method.</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">A RingData instance containing the loaded data.</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.RingData.save">
<tt class="descname">save</tt><big>(</big><em>filename</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.RingData.save" title="Permalink to this definition">¶</a></dt>
<dd><p>Serialize this RingData instance to disk.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>filename</strong> – File into which this instance should be serialized.</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.RingData.serialize_v1">
<tt class="descname">serialize_v1</tt><big>(</big><em>file_obj</em><big>)</big><a class="headerlink" href="#swift.common.ring.ring.RingData.serialize_v1" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<dl class="method">
<dt id="swift.common.ring.ring.RingData.to_dict">
<tt class="descname">to_dict</tt><big>(</big><big>)</big><a class="headerlink" href="#swift.common.ring.ring.RingData.to_dict" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
</dd></dl>
</div>
<div class="section" id="module-swift.common.ring.builder">
<span id="id2"></span><span id="ring-builder"></span><h2>Ring Builder<a class="headerlink" href="#module-swift.common.ring.builder" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="swift.common.ring.builder.RingBuilder">
<em class="property">class </em><tt class="descclassname">swift.common.ring.builder.</tt><tt class="descname">RingBuilder</tt><big>(</big><em>part_power</em>, <em>replicas</em>, <em>min_part_hours</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">object</span></tt></p>
<p>Used to build swift.common.ring.RingData instances to be written to disk
and used with swift.common.ring.Ring instances. See bin/swift-ring-builder
for example usage.</p>
<p>The instance variable devs_changed indicates if the device information has
changed since the last balancing. This can be used by tools to know whether
a rebalance request is an isolated request or due to added, changed, or
removed devices.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>part_power</strong> – number of partitions = 2**part_power.</li>
<li><strong>replicas</strong> – number of replicas for each partition</li>
<li><strong>min_part_hours</strong> – minimum number of hours between partition changes</li>
</ul>
</td>
</tr>
</tbody>
</table>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.add_dev">
<tt class="descname">add_dev</tt><big>(</big><em>dev</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.add_dev" title="Permalink to this definition">¶</a></dt>
<dd><p>Add a device to the ring. This device dict should have a minimum of the
following keys:</p>
<table border="1" class="docutils">
<colgroup>
<col width="9%" />
<col width="91%" />
</colgroup>
<tbody valign="top">
<tr class="row-odd"><td>id</td>
<td>unique integer identifier amongst devices. Defaults to the next
id if the ‘id’ key is not provided in the dict</td>
</tr>
<tr class="row-even"><td>weight</td>
<td>a float of the relative weight of this device as compared to
others; this indicates how many partitions the builder will try
to assign to this device</td>
</tr>
<tr class="row-odd"><td>region</td>
<td>integer indicating which region the device is in</td>
</tr>
<tr class="row-even"><td>zone</td>
<td>integer indicating which zone the device is in; a given
partition will not be assigned to multiple devices within the
same (region, zone) pair if there is any alternative</td>
</tr>
<tr class="row-odd"><td>ip</td>
<td>the ip address of the device</td>
</tr>
<tr class="row-even"><td>port</td>
<td>the tcp port of the device</td>
</tr>
<tr class="row-odd"><td>device</td>
<td>the device’s name on disk (sdb1, for example)</td>
</tr>
<tr class="row-even"><td>meta</td>
<td>general use ‘extra’ field; for example: the online date, the
hardware description</td>
</tr>
</tbody>
</table>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">This will not rebalance the ring immediately as you may want to
make multiple changes for a single rebalance.</p>
</div>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>dev</strong> – device dict</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">id of device</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.change_min_part_hours">
<tt class="descname">change_min_part_hours</tt><big>(</big><em>min_part_hours</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.change_min_part_hours" title="Permalink to this definition">¶</a></dt>
<dd><p>Changes the value used to decide if a given partition can be moved
again. This restriction is to give the overall system enough time to
settle a partition to its new location before moving it to yet another
location. While no data would be lost if a partition is moved several
times quickly, it could make that data unreachable for a short period
of time.</p>
<p>This should be set to at least the average full partition replication
time. Starting it at 24 hours and then lowering it to what the
replicator reports as the longest partition cycle is best.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>min_part_hours</strong> – new value for min_part_hours</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.copy_from">
<tt class="descname">copy_from</tt><big>(</big><em>builder</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.copy_from" title="Permalink to this definition">¶</a></dt>
<dd><p>Reinitializes this RingBuilder instance from data obtained from the
builder dict given. Code example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">b</span> <span class="o">=</span> <span class="n">RingBuilder</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span> <span class="c"># Dummy values</span>
<span class="n">b</span><span class="o">.</span><span class="n">copy_from</span><span class="p">(</span><span class="n">builder</span><span class="p">)</span>
</pre></div>
</div>
<p>This is to restore a RingBuilder that has had its b.to_dict()
previously saved.</p>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.get_balance">
<tt class="descname">get_balance</tt><big>(</big><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.get_balance" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the balance of the ring. The balance value is the highest
percentage off the desired amount of partitions a given device
wants. For instance, if the “worst” device wants (based on its
weight relative to the sum of all the devices’ weights) 123
partitions and it has 124 partitions, the balance value would
be 0.83 (1 extra / 123 wanted * 100 for percentage).</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body">balance of the ring</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.get_part_devices">
<tt class="descname">get_part_devices</tt><big>(</big><em>part</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.get_part_devices" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the devices that are responsible for the partition,
filtering out duplicates.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>part</strong> – partition to get devices for</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">list of device dicts</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.get_ring">
<tt class="descname">get_ring</tt><big>(</big><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.get_ring" title="Permalink to this definition">¶</a></dt>
<dd><p>Get the ring, or more specifically, the swift.common.ring.RingData.
This ring data is the minimum required for use of the ring. The ring
builder itself keeps additional data such as when partitions were last
moved.</p>
</dd></dl>
<dl class="classmethod">
<dt id="swift.common.ring.builder.RingBuilder.load">
<em class="property">classmethod </em><tt class="descname">load</tt><big>(</big><em>builder_file</em>, <em>open=<built-in function open></em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.load" title="Permalink to this definition">¶</a></dt>
<dd><p>Obtain RingBuilder instance of the provided builder file</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>builder_file</strong> – path to builder file to load</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">RingBuilder instance</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.pretend_min_part_hours_passed">
<tt class="descname">pretend_min_part_hours_passed</tt><big>(</big><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.pretend_min_part_hours_passed" title="Permalink to this definition">¶</a></dt>
<dd><p>Override min_part_hours by marking all partitions as having been moved
255 hours ago. This can be used to force a full rebalance on the next
call to rebalance.</p>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.rebalance">
<tt class="descname">rebalance</tt><big>(</big><em>seed=None</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.rebalance" title="Permalink to this definition">¶</a></dt>
<dd><p>Rebalance the ring.</p>
<p>This is the main work function of the builder, as it will assign and
reassign partitions to devices in the ring based on weights, distinct
zones, recent reassignments, etc.</p>
<p>The process doesn’t always perfectly assign partitions (that’d take a
lot more analysis and therefore a lot more time – I had code that did
that before). Because of this, it keeps rebalancing until the device
skew (number of partitions a device wants compared to what it has) gets
below 1% or doesn’t change by more than 1% (only happens with ring that
can’t be balanced no matter what – like with 3 zones of differing
weights with replicas set to 3).</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body">(number_of_partitions_altered, resulting_balance)</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.remove_dev">
<tt class="descname">remove_dev</tt><big>(</big><em>dev_id</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.remove_dev" title="Permalink to this definition">¶</a></dt>
<dd><p>Remove a device from the ring.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">This will not rebalance the ring immediately as you may want to
make multiple changes for a single rebalance.</p>
</div>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>dev_id</strong> – device id</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.save">
<tt class="descname">save</tt><big>(</big><em>builder_file</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.save" title="Permalink to this definition">¶</a></dt>
<dd><p>Serialize this RingBuilder instance to disk.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>builder_file</strong> – path to builder file to save</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.search_devs">
<tt class="descname">search_devs</tt><big>(</big><em>search_values</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.search_devs" title="Permalink to this definition">¶</a></dt>
<dd><p>Search devices by parameters.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>search_values</strong> – a dictionary with search values to filter
devices, supported parameters are id,
region, zone, ip, port, replication_ip,
replication_port, device, weight, meta</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">list of device dicts</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.set_dev_weight">
<tt class="descname">set_dev_weight</tt><big>(</big><em>dev_id</em>, <em>weight</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.set_dev_weight" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the weight of a device. This should be called rather than just
altering the weight key in the device dict directly, as the builder
will need to rebuild some internal state to reflect the change.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">This will not rebalance the ring immediately as you may want to
make multiple changes for a single rebalance.</p>
</div>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><strong>dev_id</strong> – device id</li>
<li><strong>weight</strong> – new weight for device</li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.set_replicas">
<tt class="descname">set_replicas</tt><big>(</big><em>new_replica_count</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.set_replicas" title="Permalink to this definition">¶</a></dt>
<dd><p>Changes the number of replicas in this ring.</p>
<p>If the new replica count is sufficiently different that
self._replica2part2dev will change size, sets
self.devs_changed. This is so tools like
bin/swift-ring-builder can know to write out the new ring
rather than bailing out due to lack of balance change.</p>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.to_dict">
<tt class="descname">to_dict</tt><big>(</big><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.to_dict" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns a dict that can be used later with copy_from to
restore a RingBuilder. swift-ring-builder uses this to
pickle.dump the dict to a file and later load that dict into
copy_from.</p>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.validate">
<tt class="descname">validate</tt><big>(</big><em>stats=False</em><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.validate" title="Permalink to this definition">¶</a></dt>
<dd><p>Validate the ring.</p>
<p>This is a safety function to try to catch any bugs in the building
process. It ensures partitions have been assigned to real devices,
aren’t doubly assigned, etc. It can also optionally check the even
distribution of partitions across devices.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>stats</strong> – if True, check distribution of partitions across devices</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">if stats is True, a tuple of (device_usage, worst_stat), else
(None, None). device_usage[dev_id] will equal the number of
partitions assigned to that device. worst_stat will equal the
number of partitions the worst device is skewed from the
number it should have.</td>
</tr>
<tr class="field-odd field"><th class="field-name" colspan="2">Raises RingValidationError:</th></tr>
<tr class="field-odd field"><td> </td><td class="field-body">problem was found with the ring.</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="swift.common.ring.builder.RingBuilder.weight_of_one_part">
<tt class="descname">weight_of_one_part</tt><big>(</big><big>)</big><a class="headerlink" href="#swift.common.ring.builder.RingBuilder.weight_of_one_part" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns the weight of each partition as calculated from the
total weight of all the devices.</p>
</dd></dl>
</dd></dl>
</div>
</div>
</div>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="proxy.html" title="Proxy"
>next</a> |</li>
<li class="right" >
<a href="logs.html" title="Logs"
>previous</a> |</li>
<li><a href="index.html">swift 1.13.1 documentation</a> »</li>
</ul>
</div>
<div class="footer">
© Copyright 2014, OpenStack Foundation.
Last updated on Apr 17, 2014.
Created using <a href="http://sphinx-doc.org/">Sphinx</a> 1.2.2.
</div>
</body>
</html>
|