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gzc
Asked: 2015-10-23 01:48:04 +0800 CST

mongo 将独立转换为副本集会导致服务关闭

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我有独立的 node1 已经运行了很长时间。现在我想将其转换为副本集。我按照https://docs.mongodb.org/v2.4/tutorial/convert-standalone-to-replica-set/中的步骤将独立转换为副本集。

在连接到主要的 mongo 客户端中添加成员后，命令行提示符从更改ReplicaSet0:PRIMARY>为ReplicaSet0:SECONDARY>. 然后我发现我的制作服务下降了。

我检查了我的哨兵（一个错误收集服务），发现我的 Ruby 代码抛出了很多错误：

Moped::Errors::ConnectionFailure: Could not connect to a primary node for replica set #<Moped::Cluster:28315820 @seeds=[<Moped::Node resolved_address="10.128.129.90:27017">, <Moped::Node resolved_address="10.128.130.139:27017">]>

这些是我的操作和 mongo 输出：

ReplicaSet0:PRIMARY> rs.add("node2")
{ "ok" : 1 }
ReplicaSet0:PRIMARY> rs.conf()
{
  "_id" : "ReplicaSet0",
  "version" : 2,
  "members" : [
    {
      "_id" : 0,
      "host" : "node1:27017"
    },
    {
      "_id" : 1,
      "host" : "node2:27017"
    }
  ]
}
ReplicaSet0:PRIMARY> rs.status()
Thu Oct 22 15:40:13.762 DBClientCursor::init call() failed
Thu Oct 22 15:40:13.763 Error: error doing query: failed at src/mongo/shell/query.js:78
Thu Oct 22 15:40:13.763 trying reconnect to 127.0.0.1:27017
Thu Oct 22 15:40:13.764 reconnect 127.0.0.1:27017 ok
ReplicaSet0:SECONDARY>

可以看到PRIMARY变成了SECONDARY。为什么会这样？我认为这导致我的服务下降。我该如何避免呢？请帮我。

更新0：

mongo.conf（是的，就是这样。）

dbpath=/data/mongodb
logpath=/var/log/mongodb/mongodb.log
logappend=true
bind_ip = 0.0.0.0
journal=true
replSet=ReplicaSet0

更新1：rs.status()

ReplicaSet0:SECONDARY> rs.status()
{
  "set" : "ReplicaSet0",
  "date" : ISODate("2015-10-22T07:58:14Z"),
  "myState" : 2,
  "members" : [
    {
      "_id" : 0,
      "name" : "kuankr:27017",
      "health" : 1,
      "state" : 2,
      "stateStr" : "SECONDARY",
      "uptime" : 2463,
      "optime" : Timestamp(1445499598, 19),
      "optimeDate" : ISODate("2015-10-22T07:39:58Z"),
      "self" : true
    },
    {
      "_id" : 1,
      "name" : "mongo-primary:27017",
      "health" : 0,
      "state" : 8,
      "stateStr" : "(not reachable/healthy)",
      "uptime" : 0,
      "optime" : Timestamp(0, 0),
      "optimeDate" : ISODate("1970-01-01T00:00:00Z"),
      "lastHeartbeat" : ISODate("2015-10-22T07:58:13Z"),
      "lastHeartbeatRecv" : ISODate("1970-01-01T00:00:00Z"),
      "pingMs" : 0
    }
  ],
  "ok" : 1
}

从 mongodb.log 中挑选一些相关的行

34325 Thu Oct 22 15:39:52.139 [conn397] replSet replSetReconfig config object parses ok, 2 members specified 
34326 Thu Oct 22 15:39:54.599 [conn397] replSet replSetReconfig [2]
34327 Thu Oct 22 15:39:54.599 [conn397] replSet info saving a newer config version to local.system.replset
34328 Thu Oct 22 15:39:54.607 [conn397] replSet saveConfigLocally done 
34329 Thu Oct 22 15:39:54.607 [conn397] replSet info : additive change to configuration
34330 Thu Oct 22 15:39:54.607 [conn397] replSet replSetReconfig new config saved locally
34331 Thu Oct 22 15:39:54.607 [conn397] command admin.$cmd command: { replSetReconfig: { _id: "ReplicaSet0", version: 2, members: [ { _id: 0, host: "kuankr:27017" }, { _id:       1.0, host: "mongo-primary" } ] } } ntoreturn:1 keyUpdates:0 locks(micros) W:8249 reslen:37 2467ms
34332 Thu Oct 22 15:39:54.612 [rsHealthPoll] replSet member mongo-primary:27017 is up
34333 Thu Oct 22 15:39:54.612 [rsMgr] replSet total number of votes is even - add arbiter or give one member an extra vote
34334 Thu Oct 22 15:40:08.610 [rsHealthPoll] DBClientCursor::init call() failed
34335 Thu Oct 22 15:40:08.750 [rsHealthPoll] replSet info mongo-primary:27017 is down (or slow to respond):
34336 Thu Oct 22 15:40:08.750 [rsHealthPoll] replSet member mongo-primary:27017 is now in state DOWN
34337 Thu Oct 22 15:40:08.750 [rsMgr] can't see a majority of the set, relinquishing primary
34338 Thu Oct 22 15:40:08.750 [rsMgr] replSet relinquishing primary state
34339 Thu Oct 22 15:40:08.750 [rsMgr] replSet SECONDARY
34340 Thu Oct 22 15:40:08.750 [rsMgr] replSet closing client sockets after relinquishing primary
34341 Thu Oct 22 15:40:08.751 [conn4] end connection 10.128.132.214:47738 (61 connections now open) * 
34402 Thu Oct 22 15:40:08.755 [conn385] end connection 127.0.0.1:35975 (1 connection now open)
34414 Thu Oct 22 15:40:15.895 [rsMgr] replSet info electSelf 0
34415 Thu Oct 22 15:40:15.896 [rsMgr] replSet couldn't elect self, only received 1 votes
34425 Thu Oct 22 15:40:21.897 [rsMgr] replSet info electSelf 0
34426 Thu Oct 22 15:40:21.897 [rsMgr] replSet couldn't elect self, only received 1 votes
34465 Thu Oct 22 15:40:35.897 [rsHealthPoll] DBClientCursor::init call() failed
34466 Thu Oct 22 15:40:35.898 [rsHealthPoll] replSet info mongo-primary:27017 is down (or slow to respond):
34467 Thu Oct 22 15:40:35.898 [rsMgr] replSet can't see a majority, will not try to elect self
34503 Thu Oct 22 15:40:43.899 [rsHealthPoll] replSet member mongo-primary:27017 is up
34504 Thu Oct 22 15:40:43.899 [rsMgr] replSet info electSelf 0
34505 Thu Oct 22 15:40:43.900 [rsMgr] replSet couldn't elect self, only received 1 votes
mongodb replication

1 个回答

  1. Best Answer

    基本上，评论中的场景就是这里发生的事情。您已向集合 (mongo-primary) 添加了一个新主机，并且无法从您的原始主机 (kuankr) 访问该主机。这意味着您有一个包含 2 个主机的副本集，但只有一个健康的。发生这种情况时，您无法满足选举初选的要求 - 即需要超过 50% 的选票（或严格多数）才能选举初选。

    在 2 节点集中，两个节点都必须可用并投票选举主节点。在 3 个节点的集合中，您需要 3 个中的 2 个，在 4 个节点的集合中，您需要 4 个中的 3 个，在 5 个节点的集合中，您需要 5 个中的 3 个，依此类推。

    这就是为什么总是建议您的集合中有奇数个节点的原因。我建议添加一个可以由您的原始主节点访问的仲裁器，以便可以再次选举它。然后，在解决当前问题后，找出原始主节点无法与新节点通信的原因（最常见的问题：防火墙、路由、新节点上的绑定 IP 不正确）。

    根据评论更新：

    如果助手不能在辅助设备上工作，要强制添加，那么您可以执行以下操作：

    cfg = rs.conf()
// here's what my sample config member array looks like - adjust as necessary
> cfg.members 
[
    {
        "_id" : 0,
        "host" : "mongod_A.example.net:27017"
    },
    {
        "_id" : 1,
        "host" : "mongod_B.example.net:27017"
    }
]
// let's manually add an arbiter
> cfg.members[2] = {
... "_id" : 2,
... "host": "arbiter:27017",
... "arbiter": true
... }
// now our cfg object looks like this
> cfg
{
    "_id" : "rs",
    "version" : 7,
    "members" : [
        {
            "_id" : 0,
            "host" : "mongod_A.example.net:27017"
        },
        {
            "_id" : 1,
            "host" : "mongod_B.example.net:27017"
        },
        {
            "_id" : 2,
            "host" : "arbiter:27017",
            "arbiter" : true
        }
    ]
}
// Finally, reconfigure with force on the secondary
rs.reconfig(cfg, {force : true})

    您也可以使用此类似过程删除“坏”节点

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