java - WritableServerSelector 没有从集群中选择服务器

Question

作为 MongoDB 的新手，我正在尝试将一个简单的文档插入到我新安装的 mongoDB (v3.2.4) 中。使用 MongoDB Driver 3.2.2。这是我最小化的代码:

public <classname>()
{
    public static final String COLLECTION_NAME = "logs";
    MongoClient mongoClient = new MongoClient("<server-adress>");
    MongoDatabase db = mongoClient.getDatabase("test");

    Document  data = new Document ();
    data.append(<whatever>);
    //...inserting more into document...
    db.getCollection(COLLECTION_NAME).insertOne(data); //collection should be created new

    mongoClient.close();
}

程序正在执行，但我在执行期间收到以下错误(和信息):

Mär 16, 2016 3:50:06 PM com.mongodb.diagnostics.logging.JULLogger log
INFORMATION: Cluster created with settings {hosts=[<server-adress>:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
Mär 16, 2016 3:50:06 PM com.mongodb.diagnostics.logging.JULLogger log
INFORMATION: No server chosen by WritableServerSelector from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, all=[ServerDescription{address=<server-adress>:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out
Mär 16, 2016 3:50:07 PM com.mongodb.diagnostics.logging.JULLogger log
INFORMATION: Exception in monitor thread while connecting to server <server-adress>:27017
com.mongodb.MongoSocketOpenException: Exception opening socket
    at com.mongodb.connection.SocketStream.open(SocketStream.java:63)
    at com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:114)
    at com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:128)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.net.ConnectException: Connection refused: connect
    (...) 
    at com.mongodb.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:50)
    at com.mongodb.connection.SocketStream.open(SocketStream.java:58)
    ... 3 more

Error: Timed out after 30000 ms while waiting for a server that matches WritableServerSelector. Client view of cluster state is {type=UNKNOWN, servers=[{address=<server-adress>:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.ConnectException: Connection refused: connect}}]

文档也没有插入。

当我用 insertOne() 命令注释该行时，它消失了。所以我认为这不是连接问题，对吗？

我有一些想法:

• 它与异步性有关吗？我会很惊讶，我在任何地方都没有说过我不想同步执行它。
• 是否缺少任何权限(因为这个 WritableServerSelector-Thing)？
• 它与“测试”数据库有关吗？
• MongoDB 的单机模式有问题吗？ (我不想使用副本集。)

但对于所有这些想法，我找不到真正的证据......

(请改进问题标题，我没有更好的主意......)

Answer 1

我自己解决了。

我还应该提到，我正在尝试从另一台机器连接到 MongoDB 实例。 MongoDB 预设不允许这样做。

所以我不得不在/etc/mongod.conf 文件中将 bindIp 后面的值从 127.0.0.1 更改为 0.0.0.0。

[Source]