Check the current number of connections to MongoDb
What is the command to get the number of clients connected to a particular MongoDB server?
connect to the admin database and run db.serverStatus():
> var status = db.serverStatus()
> status.connections
{"current" : 21, "available" : 15979}
>
You can directly get by querying
db.serverStatus().connections
To understand what does MongoDb's db.serverStatus().connections response mean, read the documentation here.
connections
"connections" : { "current" : <num>, "available" : <num>, "totalCreated" : NumberLong(<num>) },connections A document that reports on the status of the connections. Use these values to assess the current load and capacity requirements of the server.
connections.current The number of incoming connections from clients to the database server . This number includes the current shell session. Consider the value of connections.available to add more context to this datum.
The value will include all incoming connections including any shell connections or connections from other servers, such as replica set members or mongos instances.
connections.available The number of unused incoming connections available. Consider this value in combination with the value of connections.current to understand the connection load on the database, and the UNIX ulimit Settings document for more information about system thresholds on available connections.
connections.totalCreated Count of all incoming connections created to the server. This number includes connections that have since closed.
Connection Count by ClientIP, with Total
We use this to view the number of connections by IPAddress with a total connection count. This was really helpful in debugging an issue... just get there before hit max connections!
For Mongo Shell:
db.currentOp(true).inprog.reduce((accumulator, connection) => { ipaddress = connection.client ? connection.client.split(":")[0] : "Internal"; accumulator[ipaddress] = (accumulator[ipaddress] || 0) + 1; accumulator["TOTAL_CONNECTION_COUNT"]++; return accumulator; }, { TOTAL_CONNECTION_COUNT: 0 })
Formatted:
db.currentOp(true).inprog.reduce(
(accumulator, connection) => {
ipaddress = connection.client ? connection.client.split(":")[0] : "Internal";
accumulator[ipaddress] = (accumulator[ipaddress] || 0) + 1;
accumulator["TOTAL_CONNECTION_COUNT"]++;
return accumulator;
},
{ TOTAL_CONNECTION_COUNT: 0 }
)
Example return:
{
"TOTAL_CONNECTION_COUNT" : 331,
"192.168.253.72" : 8,
"192.168.254.42" : 17,
"127.0.0.1" : 3,
"192.168.248.66" : 2,
"11.178.12.244" : 2,
"Internal" : 41,
"3.100.12.33" : 86,
"11.148.23.34" : 168,
"81.127.34.11" : 1,
"84.147.25.17" : 3
}
(the 192.x.x.x addresses at Atlas internal monitoring)
"Internal" are internal processes that don't have an external client. You can view a list of these with this:
db.currentOp(true).inprog.filter(connection => !connection.client).map(connection => connection.desc);
db.serverStatus() gives no of connections opend and avail but not shows the connections from which client. For more info you can use this command sudo lsof | grep mongod | grep TCP. I need it when i did replication and primary node have many client connection greater than secondary.
$ sudo lsof | grep mongod | grep TCP
mongod 5733 Al 6u IPv4 0x08761278 0t0 TCP *:28017 (LISTEN)
mongod 5733 Al 7u IPv4 0x07c7eb98 0t0 TCP *:27017 (LISTEN)
mongod 5733 Al 9u IPv4 0x08761688 0t0 TCP 192.168.1.103:27017->192.168.1.103:64752 (ESTABLISHED)
mongod 5733 Al 12u IPv4 0x08761a98 0t0 TCP 192.168.1.103:27017->192.168.1.103:64754 (ESTABLISHED)
mongod 5733 Al 13u IPv4 0x095fa748 0t0 TCP 192.168.1.103:27017->192.168.1.103:64770 (ESTABLISHED)
mongod 5733 Al 14u IPv4 0x095f86c8 0t0 TCP 192.168.1.103:27017->192.168.1.103:64775 (ESTABLISHED)
mongod 5733 Al 17u IPv4 0x08764748 0t0 TCP 192.168.1.103:27017->192.168.1.103:64777 (ESTABLISHED)
This shows that I currently have five connections open to the MongoDB port (27017) on my computer. In my case I'm connecting to MongoDB from a Scalatra server, and I'm using the MongoDB Casbah driver, but you'll see the same lsof TCP connections regardless of the client used (as long as they're connecting using TCP/IP).
You can just use
db.serverStatus().connections
Also, this function can help you spot the IP addresses connected to your Mongo DB
db.currentOp(true).inprog.forEach(function(x) { print(x.client) })
I tried to see all connections for mongo database by following command.
netstat -anp --tcp --udp | grep mongo
This command can show every tcp connection for mongodb in more detail.
tcp 0 0 10.26.2.185:27017 10.26.2.1:2715 ESTABLISHED 1442/./mongod
tcp 0 0 10.26.2.185:27017 10.26.2.1:1702 ESTABLISHED 1442/./mongod
tcp 0 0 10.26.2.185:27017 10.26.2.185:39506 ESTABLISHED 1442/./mongod
tcp 0 0 10.26.2.185:27017 10.26.2.185:40021 ESTABLISHED 1442/./mongod
tcp 0 0 10.26.2.185:27017 10.26.2.185:39509 ESTABLISHED 1442/./mongod
tcp 0 0 10.26.2.185:27017 10.26.2.184:46062 ESTABLISHED 1442/./mongod
tcp 0 0 10.26.2.185:27017 10.26.2.184:46073 ESTABLISHED 1442/./mongod
tcp 0 0 10.26.2.185:27017 10.26.2.184:46074 ESTABLISHED 1442/./mongod