MongoDB monitoring with Netdata

Monitors performance and health metrics of MongoDB.

Requirements

• python-pymongo package v2.4+.

You need to install it manually.

Number of charts depends on mongodb version, storage engine and other features (replication):

1. Read requests:

   • query
   • getmore (operation the cursor executes to get additional data from query)

2. Write requests:

   • insert
   • delete
   • update

3. Active clients:

   • readers (number of clients with read operations in progress or queued)
   • writers (number of clients with write operations in progress or queued)

4. Journal transactions:

   • commits (count of transactions that have been written to the journal)

5. Data written to the journal:

   • volume (volume of data)

6. Background flush (MMAPv1):

   • average ms (average time taken by flushes to execute)
   • last ms (time taken by the last flush)

7. Read tickets (WiredTiger):

   • in use (number of read tickets in use)
   • available (number of available read tickets remaining)

8. Write tickets (WiredTiger):

   • in use (number of write tickets in use)
   • available (number of available write tickets remaining)

9. Cursors:

• opened (number of cursors currently opened by MongoDB for clients)
• timedOut (number of cursors that have timed)
• noTimeout (number of open cursors with timeout disabled)

10. Connections:

    • connected (number of clients currently connected to the database server)
    • unused (number of unused connections available for new clients)

11. Memory usage metrics:

    • virtual
    • resident (amount of memory used by the database process)
    • mapped
    • non mapped

12. Page faults:

    • page faults (number of times MongoDB had to request from disk)

13. Cache metrics (WiredTiger):

    • percentage of bytes currently in the cache (amount of space taken by cached data)
    • percentage of tracked dirty bytes in the cache (amount of space taken by dirty data)

14. Pages evicted from cache (WiredTiger):

    • modified
    • unmodified

15. Queued requests:

    • readers (number of read request currently queued)
    • writers (number of write request currently queued)

16. Errors:

    • msg (number of message assertions raised)
    • warning (number of warning assertions raised)
    • regular (number of regular assertions raised)
    • user (number of assertions corresponding to errors generated by users)

17. Storage metrics (one chart for every database)

    • dataSize (size of all documents + padding in the database)
    • indexSize (size of all indexes in the database)
    • storageSize (size of all extents in the database)

18. Documents in the database (one chart for all databases)

• documents (number of objects in the database among all the collections)

19. tcmalloc metrics

    • central cache free
    • current total thread cache
    • pageheap free
    • pageheap unmapped
    • thread cache free
    • transfer cache free
    • heap size

20. Commands total/failed rate

    • count
    • createIndex
    • delete
    • eval
    • findAndModify
    • insert

21. Locks metrics (acquireCount metrics - number of times the lock was acquired in the specified mode)

    • Global lock
    • Database lock
    • Collection lock
    • Metadata lock
    • oplog lock

22. Replica set members state

    • state

23. Oplog window

    • window (interval of time between the oldest and the latest entries in the oplog)

24. Replication lag

    • member (time when last entry from the oplog was applied for every member)

25. Replication set member heartbeat latency

    • member (time when last heartbeat was received from replica set member)

Prerequisite

Create a read-only user for Netdata in the admin database.

1. Authenticate as the admin user.

use admin
db.auth("admin", "<MONGODB_ADMIN_PASSWORD>")

2. Create a user.

# MongoDB 2.x.
db.addUser("netdata", "<UNIQUE_PASSWORD>", true)

# MongoDB 3.x or higher.
db.createUser({
  "user":"netdata",
  "pwd": "<UNIQUE_PASSWORD>",
  "roles" : [
    {role: 'read', db: 'admin' },
    {role: 'clusterMonitor', db: 'admin'},
    {role: 'read', db: 'local' }
  ]
})

Configuration

Edit the python.d/mongodb.conf configuration file using edit-config from the Netdata config directory, which is typically at /etc/netdata.

cd /etc/netdata   # Replace this path with your Netdata config directory, if different
sudo ./edit-config python.d/mongodb.conf

Sample:

local:
    name : 'local'
    authdb: 'admin'
    host : '127.0.0.1'
    port : 27017
    user : 'netdata'
    pass : 'netdata'

If no configuration is given, module will attempt to connect to mongodb daemon on 127.0.0.1:27017 address

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