MongoDb primary replica becomes secondary if secondary fails - mongodb

Question

I have 2 mongo replicas. One is primary and the second one is secondary. If I stop the secondary replica, the primary one becomes secondary and I lost the write permissions.
Here are my configs:
replica:PRIMARY> rs.status()
{
"set" : "replica",
"date" : ISODate("2016-02-26T11:27:50.140Z"),
"myState" : 1,
"members" : [
{
"_id" : 1,
"name" : "192.168.5.44:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 80,
"optime" : Timestamp(1456486069, 1),
"optimeDate" : ISODate("2016-02-26T11:27:49Z"),
"electionTime" : Timestamp(1456485992, 1),
"electionDate" : ISODate("2016-02-26T11:26:32Z"),
"configVersion" : 82935,
"self" : true
},
{
"_id" : 2,
"name" : "192.168.5.34:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 79,
"optime" : Timestamp(1456486067, 2),
"optimeDate" : ISODate("2016-02-26T11:27:47Z"),
"lastHeartbeat" : ISODate("2016-02-26T11:27:48.874Z"),
"lastHeartbeatRecv" : ISODate("2016-02-26T11:27:48.930Z"),
"pingMs" : 1,
"syncingTo" : "192.168.5.44:27017",
"configVersion" : 82935
}
],
"ok" : 1
}
replica:SECONDARY> rs.status()
{
"set" : "replica",
"date" : ISODate("2016-02-26T11:21:38.574Z"),
"myState" : 2,
"syncingTo" : "192.168.5.44:27017",
"members" : [
{
"_id" : 1,
"name" : "192.168.5.44:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 1306,
"optime" : Timestamp(1456485695, 3),
"optimeDate" : ISODate("2016-02-26T11:21:35Z"),
"lastHeartbeat" : ISODate("2016-02-26T11:21:36.602Z"),
"lastHeartbeatRecv" : ISODate("2016-02-26T11:21:37.412Z"),
"pingMs" : 0,
"electionTime" : Timestamp(1456484393, 1),
"electionDate" : ISODate("2016-02-26T10:59:53Z"),
"configVersion" : 82935
},
{
"_id" : 2,
"name" : "192.168.5.34:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1306,
"optime" : Timestamp(1456485697, 1),
"optimeDate" : ISODate("2016-02-26T11:21:37Z"),
"syncingTo" : "192.168.5.44:27017",
"configVersion" : 82935,
"self" : true
}
],
"ok" : 1
}
replica:SECONDARY> cfg = rs.conf()
{
"_id" : "replica",
"version" : 82935,
"members" : [
{
"_id" : 1,
"host" : "192.168.5.44:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 2,
"tags" : {
},
"slaveDelay" : 0,
"votes" : 1
},
{
"_id" : 2,
"host" : "192.168.5.34:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slaveDelay" : 0,
"votes" : 1
}
],
"settings" : {
"chainingAllowed" : true,
"heartbeatTimeoutSecs" : 10,
"getLastErrorModes" : {
},
"getLastErrorDefaults" : {
"w" : 1,
"wtimeout" : 0
}
}
}
Even if I shutdown the primary replica, the secondary won't become primary.
If you need any other details notify me.
Thank you for help!

Answer 1

MongoDB need the majority of members to accomplish an election. In a 2 members replication set, both member must be available to reach the majority. If one is down, another cannot be elected to primary.