/* * This test demonstrates 2 primaries existing in the same replica set and both primaries * can satisfy majority write concern. * * Basically the test simulates below scenario * Note: 'P' refers primary, 'S' refers to secondary. * 1) [P, S0, S1] // Start a 3 node replica set. * 2) Partition A: [P] Partition B: [S0->P, S1] // Create n/w partition A & B. * 3) Partition A: [P, S2] Partition B: [P, S1] // Replace S1 by a new node S2 to Partition A using the member id of S1. */ load('jstests/replsets/rslib.js'); (function() { 'use strict'; // Start a 3 node replica set. // [P, S0, S1] const rst = new ReplSetTest({ nodes: [{}, {}, {rsConfig: {priority: 0}}], useBridge: true }); // Disable Chaining and disable automatic election from happening due to liveness timeout. var config = rst.getReplSetConfig(); config.settings = config.settings || {}; config.settings["chainingAllowed"] = false; config.settings["electionTimeoutMillis"] = ReplSetTest.kForeverMillis; rst.startSet(); rst.initiate(config); const dbName = jsTest.name(); const collName = "coll"; let primary1 = rst.getPrimary(); const primaryDB = primary1.getDB(dbName); const primaryColl = primaryDB[collName]; const secondaries = rst.getSecondaries(); jsTestLog("Do a document write"); assert.commandWorked(primaryColl.insert({_id: 1, x: 1}, {"writeConcern": {"w": 3}})); rst.awaitReplication(); // Create a n/w partition such that we result in this state [P] [S0, S1]. jsTestLog("Disconnect primary1 from all secondaries"); primary1.disconnect([secondaries[0], secondaries[1]]); jsTestLog("Make secondary0 to be become primary"); assert.commandWorked(secondaries[0].adminCommand({"replSetStepUp": 1})); // Now our network topology will be [P] [S0->P, S1]. jsTestLog("Wait for secondary0 to become master"); checkLog.contains(secondaries[0], "Transition to primary complete"); let primary2 = secondaries[0]; // Make sure the new writes is able to propagate to the newly added node. jsTestLog("Do a document write on the primary2"); assert.commandWorked( primary2.getDB(dbName)[collName].insert({_id: 2, x: 2}, {"writeConcern": {"w": "majority"}})); jsTestLog("Adding a new voting node to the replica set"); let origConfig = rst.getReplSetConfigFromNode(primary1.nodeId); const node4 = rst.add({ rsConfig: {priority: 0, votes: 1}, setParameter: { 'numInitialSyncAttempts': 1 } }); // Simulate this network topology [P, S2] [P, S1]. node4.disconnect([secondaries[0], secondaries[1]]); // Run a reconfig command on the primary1 to add node 4 var newConfig = rst.getReplSetConfig(); // Only reset members. origConfig.members[2].host = newConfig.members[3].host; origConfig.version += 1; assert.adminCommandWorkedAllowingNetworkError( primary1, {replSetReconfig: origConfig, maxTimeMS: ReplSetTest.kDefaultTimeoutMS}); jsTestLog( "Do some document writes to verify we have 2 primaries and both satisfy write concern majority"); assert.commandWorked(primary1.getDB(dbName)[collName].insert({_id: 3, x: "primary1 Doc"}, {"writeConcern": {"w": "majority"}})); assert.commandWorked(primary2.getDB(dbName)[collName].insert({_id: 6, x: "primary2 Doc"}, {"writeConcern": {"w": "majority"}})); jsTestLog("Verify our primary1 can be get re-elected."); assert.commandWorked(primary1.adminCommand({"replSetStepDown": 1000, "force": true})); assert.commandWorked(primary1.adminCommand({replSetFreeze: 0})); assert.commandWorked(primary1.adminCommand({"replSetStepUp": 1})); jsTestLog("Test completed"); rst.stopSet(); }());