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 cl

Answer 1

I disabled TLS (inside Spring Data MongoDB), and now the transaction feature with the developement release 3.7.9 works fine.

Answer 2

With the reference to the answer give by @kakabali, I have few a bit different scenario and configure it.

I am configure mongo with spring boot and try to use transactions management and getting the error:

com.mongodb.MongoClientException: Sessions are not supported by the MongoDB cluster to which this client is connected at

I follow few of the steps given by above answer and added few:

Change the mongo.cfg and added this

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

Restart the service as I am using Windows10.

Open mongo console and run rs.initilize()

Answer 3

Make sure you're using the updated API - for example:

MongoClient mongoClient = MongoClients.create();
MongoDatabase dataBase = mongoClient.getDatabase("mainDatabase");
MongoCollection<Document> collection = dataBase.getCollection("entities");

Also make sure you have mongo.exe open.

Answer 4

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

Answer 5

I was having the same issue when I was trying to connect it to a single standalone mongo instance, however as written in the official documentation, that Mongo supports transaction feature for a replica set. So, I then tried to create a replica set with all instances on MongoDB 4.0.0, I was able to successfully execute the code. So, Start a replica set (3 members), then try to execute the code, the issue will be resolved.

NB : you can configure a replica set on the same machine for tests https://docs.mongodb.com/manual/tutorial/deploy-replica-set-for-testing/

Answer 6

Replica set is the resolution for the issue for sure

But doing replica of 3 nodes is not mandatory.

Solution 1 (for standalone setup)

For standalone mongo installation you can skip configuring 2nd or 3rd node as described on the official mongo documentations here

And you'll need to set a replSetName in the configuration

replication:
   oplogSizeMB: <int>
   replSetName: <string>
   enableMajorityReadConcern: <boolean>

and then run details of which are here

rs.initiate()

after this the connection string would be like below:-

mongodb://localhost:27017/<database_name>?replicaSet=<replSet_Name>

keys above that you need to replace:-

database_name = name of the database

replSet_Name = name of the replica set you setup in the above configuration

Solution 2 (only for docker based requirement)

Example Docker image with single node replica set acting as primary node for development environment is as below:-

I had hosted the docker image on the docker hub

docker pull krnbr/mongo:latest

Contents of the same Dockerfile are below:-

FROM mongo
RUN echo "rs.initiate({'_id':'rs0','members':[{'_id':0,'host':'127.0.0.1:27017'}]});" > /docker-entrypoint-initdb.d/replica-init.js
RUN cat /docker-entrypoint-initdb.d/replica-init.js
CMD [ "--bind_ip_all", "--replSet", "rs0" ]

Docker run command (replace with the image name that you build yoursef or use the on shared above i.e krnbr/mongo):-

without volume

docker run -d --name mongo -p 27017:27017 <Image Name> mongod --replSet rs0 --port 27017

with volume

docker run -d --name mongo -p 27017:27017 -v ~/.mongodb:/data/db <Image Name> mongod --replSet rs0 --port 27017

for supporting binding of any ip

docker run -d --name mongo -p 27017:27017 -v ~/.mongodb:/data/db <Image Name> mongod --bind_ip_all --replSet rs0 --port 27017