连接到 MongoDB 副本集 - pymongo

Question

So I have a cluster of 3 mongo replica sets. The primary (master) is at rs1, while rs2 and rs3 are secondaries. However, the primary may change, for example, rs2 may be the primary at any given time due to some configuration issue. Therefore, I need to be able to connect to the appropriate replica set. Let's say they are at rs1=10.1.1.1 , rs2=10.1.1.2 and rs3=10.1.1.3 . Here's how I'm connecting to Mongo:

mongoserver_uri = "mongodb://{0}:{1}@{2}:{3}/admin".format(
                    username, password, host, port)
self.log.info("------- Mongo Server URI: %s --------" % mongoserver_uri)
self.client = pymongo.MongoClient(host=mongoserver_uri, ssl=True,
                                  ssl_cert_reqs=ssl.CERT_NONE)

However if, like explained, the replica set primary changes to let's say rs3 then I would be unable to connect to Mongo:

  File "/home/ubuntu/myproject/mongodb.py", line 165, in clear_collections
    collection.remove()
  File "/usr/local/lib/python2.7/site-packages/pymongo/collection.py", line 2258, in remove
    return self._delete(sock_info, spec_or_id, multi, write_concern)
  File "/usr/local/lib/python2.7/site-packages/pymongo/collection.py", line 916, in _delete
    codec_options=self.codec_options)
  File "/usr/local/lib/python2.7/site-packages/pymongo/pool.py", line 218, in command
    self._raise_connection_failure(error)
  File "/usr/local/lib/python2.7/site-packages/pymongo/pool.py", line 346, in _raise_connection_failure
    raise error
pymongo.errors.NotMasterError: not master

How can I specify the other replica sets to the MongoClient ?

Answer 1

From the docs

A connection to a replica set can be made using the MongoClient() constructor, specifying one or more members of the set, along with the replica set name.

mongoserver_uri = "mongodb://{0}:{1}@{2}:{3}/admin".format(
                    username, password, host, port)
self.log.info("------- Mongo Server URI: %s --------" % mongoserver_uri)
self.client = pymongo.MongoClient(host=mongoserver_uri, ssl=True,
                                  ssl_cert_reqs=ssl.CERT_NONE,
                                  replicaset='name_of_set')

As long as the server you connect to is online at initially, the MongoClient will find all members of the replicaSet and automatically attempt to find a new primary on failover.

Answer 2

在您的 MongoClient 中，您需要告诉 pymongo 您正在连接到副本集，以便它可以发现集合中的所有成员https://api.mongodb.com/python/current/examples/high_availability.html#id1

Answer 3

dbconnect = MongoClient('mongodb://mongos01:27017,mongos02:27017,mongos03:27017/?replicaSet=seplicaSetName',username='username',password='password',authSource='dbname',authMechanism='SCRAM- SHA1')