MongoError is an error produced by the MongoDB database server, which indicates that it's not able to communicate with the master. This can be caused by a number of issues, and in this guide we will describe the steps needed to troubleshoot it.
Symptoms
The MongoError: Not Master and slaveOk= usually appears when running MongoDB queries or attempting to connect to the MongoDB server. This can be caused by a network issue, or a misconfiguration of the MongoDB server.
Solutions
Step 1: Check if Replica Set is Defined
The most common cause of the MongoError: Not Master and slaveOk= is a misconfigured replica set. To ensure that the replica set is set up correctly, you'll need to check the contents of the file /etc/mongo/mongod.conf inside the MongoDB server.
Inside this file you should find a replSet key, which should contain the name of your replica set. If this key is not present, or incorrectly named, then MongoDB will not be able to communicate with the master.
Step 2: Check Network Connectivity between Nodes
Once you've ensured that your replica set is correctly configured, you'll need to check the network connectivity between the nodes of your replica set. If the nodes are not able to communicate with each other, then MongoDB won't be able to find the master node.
To check the network connectivity between the nodes, you can use the mongo-ping command. This command allows you to ping each node of the replica set, and see if it is able to communicate with its peers.
Step 3: Check the Status of the Master Node
If the previous two steps have succeeded, then you'll need to ensure that the master node is online and available. To do this, you can use the mongo-status command, which will allow you to see the status of the master node, as well as its replicas.
If the master node is not online, then you'll need to restart it. This can be done using the mongo-restart command.
FAQs
Q1: What is the MongoError: Not Master and slaveOk error?
The MongoError: Not Master and slaveOk is an error produced by the MongoDB database server, which indicates that it's not able to communicate with the master.
Q2: What are the common causes of the MongoError: Not Master and slaveOk error?
The most common cause of the MongoError: Not Master and slaveOk is a misconfigured replica set, or a network issue between the nodes of the replica set.
Q3: How can I troubleshoot the MongoError: Not Master and slaveOk error?
To troubleshoot the MongoError: Not Master and slaveOk error, you can follow these three steps:
- Check if the replica set is correctly configured.
- Check the network connectivity between the nodes of the replica set.
- Check the status of the master node.
Q4: What command can I use to check the network connectivity between the nodes of the replica set?
The mongo-ping command can be used to check the network connectivity between the nodes of the replica set.
Q5: What command can I use to restart the master node?
The mongo-restart command can be used to restart the master node.