Issues - Monitoring MongoDB using Nagios XI.

Monitoring for mongodb using nagiosxi is straight forword but you might have some issues when we are setting up.
Here are few issues which might come up using mongodb version 3.

Issue getting monitoring data in nagios.

1. ConnectionFailure object has no attribute strip

[ahmed@localhost libexec]$ ./check_mongodb.py -H 192.168.94.137 -P 27017 -u admin -p admin
Traceback (most recent call last):
  File "./check_mongodb.py", line 1372, in <module>
    sys.exit(main(sys.argv[1:]))
  File "./check_mongodb.py", line 196, in main
    err, con = mongo_connect(host, port, ssl, user, passwd, replicaset)
  File "./check_mongodb.py", line 294, in mongo_connect
    return exit_with_general_critical(e), None
  File "./check_mongodb.py", line 310, in exit_with_general_critical
    if e.strip() == "not master":
AttributeError: 'ConnectionFailure' object has no attribute 'strip'

Solution.

e.strip() expects e to be a string, which might not be the case sometimes, so remove strip(). Change below code on line 310.

  else:
      if e.strip() == "not master":
          print "UNKNOWN - Could not get data from server:", e
          return 3

to

  else:
      if e == "not master":
          print "UNKNOWN - Could not get data from server:", e
          return 3

After the change atleast you will get an error which gives you more information.

[ahmed@localhost libexec]$ ./check_mongodb_2.py -H 192.168.94.138 -P 27017 -u admin -p admin1 -A databases -W 5 -C 10
CRITICAL - General MongoDB Error: command SON([('authenticate', 1), ('user', u'admin'), ('nonce', u'37a502d665186449'), ('key', u'd8c683f98a5e720c28a8007018ed7414')]) failed: auth failed

Next we will try to resolve, above auth failure.

2. Executing command from the nagios server.

[ahmed@localhost libexec]$ ./check_mongodb_2.py -H 192.168.94.138 -P 27017 -u admin -p admin1 -A databases -W 5 -C 10
CRITICAL - General MongoDB Error: command SON([('authenticate', 1), ('user', u'admin'), ('nonce', u'42110dc29ee7fe6b'), ('key', u'827a2b0e4af97e88560800ab86b04e57')]) failed: auth failed

On the mongodb server.

Checking on the mongodb server shows that the AuthenticationFailed due to MONGODB-CR credentials missing in the user document

2016-09-14T19:11:12.142-0700 I ACCESS   [conn114] Successfully  authenticated as principal admin on admin
2016-09-14T19:11:32.892-0700 I NETWORK  [initandlisten] connection accepted from  192.168.94.130:48657 #115 (2 connections now open)
2016-09-14T19:11:32.894-0700 I ACCESS   [conn115]  authenticate db: admin { authenticate: 1, user: "admin", nonce: "xxx", key: "xxx" }
2016-09-14T19:11:32.894-0700 I ACCESS   [conn115] Failed to authenticate admin@admin with mechanism MONGODB-CR: AuthenticationFailed: MONGODB-CR credentials missing in the user document
2016-09-14T19:11:32.895-0700 I NETWORK  [conn115] end connection 192.168.94.130:48657 (1 connection now open)
2016-09-14T19:11:54.283-0700 I NETWORK  [initandlisten] connection accepted from 192.168.94.130:48663 #116 (2 connections now open)
2016-09-14T19:11:54.284-0700 I NETWORK  [conn116] end connection 192.168.94.130:48663 (1 connection now open)
2016-09-14T19:12:07.860-0700 I NETWORK  [initandlisten] connection accepted from 192.168.94.130:48666 #117 (2 connections now open)
2016-09-14T19:12:07.861-0700 I ACCESS   [conn117] Unauthorized: not authorized on admin to execute command { listDatabases: 1 }

Solution.

1. Delete exsisting users on the database if it was already created.
2. Modify the collection admin.system.version such that the authSchema currentVersion is 3 instead of 5
3. Version 3 is using MongoDB-CR
4. Recreate your user on the databases.

NOTE : Do not do it on PRODUCTION environment, use update instead and try on test database first.

mongo
use admin
db.system.users.remove({})
db.system.version.remove({})
db.system.version.insert({ "_id" : "authSchema", "currentVersion" : 3 })

More Details Here:

• http://stackoverflow.com/a/31476552
• http://stackoverflow.com/a/29193735

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