<h1 id="raft">Raft<a aria-hidden="true" class="anchor-heading icon-link" href="#raft"></a></h1>
<h1 id="共识机制-raft">共识机制 raft<a aria-hidden="true" class="anchor-heading icon-link" href="#共识机制-raft"></a></h1>
<p>main idea is to allow a collection of machines to work as a group that can survive the failures fo some of its members.</p>
<h2 id="leader-election">leader election<a aria-hidden="true" class="anchor-heading icon-link" href="#leader-election"></a></h2>
<ul>
<li>what: in each term, elect a leader. when time out, start a new election.</li>
<li>why: one leader to recieve request and syn among all machines.</li>
<li>how: begin one election with term++, every one vote itself first and request others, if it finds other have more latest term, it will become follower.</li>
</ul>
<h2 id="log-replication">log replication<a aria-hidden="true" class="anchor-heading icon-link" href="#log-replication"></a></h2>
<ul>
<li>what: append command as a log entry.</li>
<li>why: make sure everyone has same log</li>
<li>how: commit, if consistence, duplicate leader's</li>
<li>When AppendEntries consistency check fails, decrement nextIndex and try again</li>
<li>When follower overwrites inconsistent entry, it deletes all subsequent entries    </li>
</ul>

Raft

共识机制 raft

leader election

log replication

共识机制 raft