How to configure a MongoDB cluster which supports sessions?

Question

I want to explore the new transaction feature of MongoDB and use Spring Data MongoDB. However, I get the exception message "Sessions are not supported by the MongoDB cluster to which this client is connected". Any hint regarding the config of MongoDB 3.7.9 is appreciated.

The stacktrace starts with:

com.mongodb.MongoClientException: Sessions are not supported by the MongoDB cluster to which this client is connected at com.mongodb.MongoClient.startSession(MongoClient.java:555) ~[mongodb-driver-3.8.0-beta2.jar:na] at org.springframework.data.mongodb.core.SimpleMongoDbFactory.getSession(SimpleMongoDbFactory.java:163) ~[spring-data-mongodb-2.1.0.DATAMONGO-1920-SNAPSHOT.jar:2.1.0.DATAMONGO-1920-SNAPSHOT]

Answer 1

We were able to config in local as below

• On Linux, a default /etc/mongod.conf configuration file is included when using a package manager to install MongoDB.

• On Windows, a default <install directory>/bin/mongod.cfg configuration file is included during the installation

• On macOS, a default /usr/local/etc/mongod.conf configuration file is included when installing from MongoDB’s official Homebrew tap.

Add the following config

replication:
   oplogSizeMB: 128
   replSetName: "rs0"
   enableMajorityReadConcern: true

sudo service mongod restart;

mongo;

rs.initiate({
      _id: "rs0",
      version: 1,
      members: [
         { _id: 0, host : "localhost:27017" }
      ]
   }
)

check for the config to be enabled

rs.conf()

we can use the connection URL as

mongodb://localhost/default?ssl=false&replicaSet=rs0&readPreference=primary

docs: config-options single-instance-replication