SERVER-14626 Implement quorum check functionality for use in replcia set initiate and reconfig.

1 files changed, 77 insertions, 0 deletions

diff --git a/src/mongo/db/repl/check_quorum_for_config_change.h b/src/mongo/db/repl/check_quorum_for_config_change.h
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+++ b/src/mongo/db/repl/check_quorum_for_config_change.h
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+/**
+ *    Copyright (C) 2014 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+namespace mongo {
+
+    class Status;
+
+namespace repl {
+
+    class ReplicaSetConfig;
+    class ReplicationExecutor;
+
+    /**
+     * Performs a quorum call to determine if a sufficient number of nodes are up
+     * to initiate a replica set with configuration "rsConfig".
+     *
+     * "myIndex" is the index of this node's member configuration in "rsConfig".
+     * "executor" is the event loop in which to schedule network/aysnchronous processing.
+     *
+     * For purposes of initiate, a quorum is only met if all of the following conditions
+     * are met:
+     * - All nodes respond.
+     * - No nodes other than the node running the quorum check have data.
+     * - No nodes are already joined to a replica set.
+     * - No node reports a replica set name other than the one in "rsConfig".
+     */
+    Status checkQuorumForInitiate(ReplicationExecutor* executor,
+                                  const ReplicaSetConfig& rsConfig,
+                                  const int myIndex);
+
+    /**
+     * Performs a quorum call to determine if a sufficient number of nodes are up
+     * to replace the current replica set configuration with "rsConfig".
+     *
+     * "myIndex" is the index of this node's member configuration in "rsConfig".
+     * "executor" is the event loop in which to schedule network/aysnchronous processing.
+     *
+     * For purposes of reconfig, a quorum is only met if all of the following conditions
+     * are met:
+     * - A majority of voting nodes respond.
+     * - At least one electable node responds.
+     * - No responding node reports a replica set name other than the one in "rsConfig".
+     * - All responding nodes report a config version less than the one in "rsConfig".
+     */
+    Status checkQuorumForReconfig(ReplicationExecutor* executor,
+                                  const ReplicaSetConfig& rsConfig,
+                                  const int myIndex);
+
+}  // namespace repl
+}  // namespace mongo