MongoDB 副本集 pymongo使用

搭建没有仲裁节点的副本集，推荐使用

2.清空node2的db文件夹 和 log 文件夹

 rm -rf /var/lib/mongod/*

　rm -rf /var/log/mongod/*

3.修改node2和port、replSet

vim /etc/mongod.conf

replSet = arg/192.168.1.161:27017,192.168.1.162:27017

复制mongod.conf到node2

　scp /etc/mogod.conf  node2:/etc/

4.启动三个节点，分别进入 对应的node文件夹中：

systemctl start mongod

5.连接node1节点（27017）：

mongo --host  192.168.1.161  --port  27017

6.执行初始化命令：

> config={"_id":"arg",members:[{"_id":1,"host":"192.168.1.161:27017"},{"_id":2,"host":"192.168.1.162:27017"}]}
{
    "_id" : "arg",
    "members" : [
        {
            "_id" : 1,
            "host" : "192.168.1.161:27017"
        },
        {
            "_id" : 2,
            "host" : "192.168.1.162:27017"
        }
    ]
}

> rs.initiate(config)
{
    "info" : "Config now saved locally.  Should come online in about a minute.",
    "ok" : 1
}

7.查看状态，发现有1个主节点，1个从节点。

> rs.status()
{
    "set" : "arg",
    "date" : ISODate("2018-09-06T06:50:16Z"),
    "myState" : 1,
    "members" : [
        {
            "_id" : 1,
            "name" : "192.168.1.161:27017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 1306,
            "optime" : Timestamp(1536216613, 2),
            "optimeDate" : ISODate("2018-09-06T06:50:13Z"),
            "electionTime" : Timestamp(1536216578, 1),
            "electionDate" : ISODate("2018-09-06T06:49:38Z"),
            "self" : true
        },
        {
            "_id" : 2,
            "name" : "192.168.1.162:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 50,
            "optime" : Timestamp(1536216613, 2),
            "optimeDate" : ISODate("2018-09-06T06:50:13Z"),
            "lastHeartbeat" : ISODate("2018-09-06T06:50:16Z"),
            "lastHeartbeatRecv" : ISODate("2018-09-06T06:50:15Z"),
            "pingMs" : 0,
            "syncingTo" : "192.168.1.161:27017"
        }
    ],
    "ok" : 1
}

使用MongoDB 副本集,第1个参数是主host,第2个是replSet名,第3个是模式client = MongoReplicaSetClient(eval(mongodb_set), replicaSet=mongodb_replicaSet, read_preference=eval(mongodb_read_preference))

下面getClient函数的conf

{    
    "mongodb_host" : "192.168.1.161",
    "mongodb_set" : "192.168.1.161:27017",
    "mongodb_replicaSet" : "arg",
    "mongodb_read_preference" : "ReadPreference.SECONDARY_PREFERRED",
    "mongodb_port" : 27017,
    "mongodb_user":"ceph",
    "mongodb_passwd":"monpassword",
    "is_mongo_authenticate" : 0,
    "is_mongo_replicat" : 1,
}

pymongo连接mongodb

def getClient(conf, dbname):
    '''
        conf : json  conf objet
        conf=load_conf(configfile)
        db = getClient(conf)['ceph']
        collection =db['cluster']
        cursor=collection.find_one()
        Return  a connexion to  database specified  in  conf file
        take care with authentication
    '''
    mongodb_host = conf.get("mongodb_host", "127.0.0.1")
    mongodb_port = conf.get("mongodb_port", "27017")
    mongodb_URL = "mongodb://"+mongodb_host+":"+str(mongodb_port)
    #mongodb replication
    is_mongo_replicat = conf.get("is_mongo_replicat", 0)
    mongodb_set = "'"+conf.get("mongodb_set","")+"'"
    mongodb_replicaSet =conf.get("mongodb_replicaSet",None)
    mongodb_read_preference = conf.get("mongodb_read_preference",None)
   
 
    if is_mongo_replicat ==  1:
        # 使用MongoDB 副本集,第1个参数是主host,第2个是replSet名,第3个是模式
        client = MongoReplicaSetClient(eval(mongodb_set), replicaSet=mongodb_replicaSet, read_preference=eval(mongodb_read_preference))
    else:
        #if not replicated
        client = MongoClient(mongodb_URL)
    # mongo db  authentication
    is_mongo_authenticate = conf.get("is_mongo_authenticate", 0)
    mongodb_user = conf.get("mongodb_user", "ceph")
    mongodb_passwd = conf.get("mongodb_passwd", "empty")
    if is_mongo_authenticate == 1:
        client[dbname].authenticate(mongodb_user,mongodb_passwd)
        
    return client[dbname]

8.kill 掉node6，即端口 27021

9.然后连接到node7上：mongo --host 192.168.80.128 --port 27022，查看状态，发现node7为从节点，node8为主节点了，原来的node6 不可达、不健康的。

>XbqSet:SECONDARY> rs.status()
{
    "set" : "XbqSet",
    "date" : ISODate("2017-07-27T22:08:24.894Z"),
    "myState" : 2,
    "members" : [
        {
            "_id" : 1,
            "name" : "192.168.80.128:27021",
            "health" : 0,
            "state" : 8,
            "stateStr" : "(not reachable/healthy)",
            "uptime" : 0,
            "optime" : Timestamp(0, 0),
            "optimeDate" : ISODate("1970-01-01T00:00:00Z"),
            "lastHeartbeat" : ISODate("2017-07-27T22:08:23.748Z"),
            "lastHeartbeatRecv" : ISODate("2017-07-27T22:07:43.464Z"),
            "pingMs" : 0,
            "lastHeartbeatMessage" : "Failed attempt to connect to 192.168.80.128:27021; couldn't connect to server 192.168.80.128:27021 (192.168.80.128), connection attempt failed",
            "configVersion" : -1
        },
        {
            "_id" : 2,
            "name" : "192.168.80.128:27022",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 833,
            "optime" : Timestamp(1501192872, 1),
            "optimeDate" : ISODate("2017-07-27T22:01:12Z"),
            "configVersion" : 1,
            "self" : true
        },
        {
            "_id" : 3,
            "name" : "192.168.80.128:27023",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 431,
            "optime" : Timestamp(1501192872, 1),
            "optimeDate" : ISODate("2017-07-27T22:01:12Z"),
            "lastHeartbeat" : ISODate("2017-07-27T22:08:23.409Z"),
            "lastHeartbeatRecv" : ISODate("2017-07-27T22:08:23.521Z"),
            "pingMs" : 0,
            "electionTime" : Timestamp(1501193266, 1),
            "electionDate" : ISODate("2017-07-27T22:07:46Z"),
            "configVersion" : 1
        }
    ],
    "ok" : 1
}

10.重新启动node6：mongod --config mongodb.conf

11.继续连接node7：mongo --host 192.168.80.128 --port 27022，查看状态，原来的node6 变为了 从节点。

rs.status()
{
"set" : "XbqSet",
"date" : ISODate("2017-07-27T22:12:41.275Z"),
"myState" : 2,
"members" : [
{
"_id" : 1,
"name" : "192.168.80.128:27021",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 54,
"optime" : Timestamp(1501192872, 1),
"optimeDate" : ISODate("2017-07-27T22:01:12Z"),
"lastHeartbeat" : ISODate("2017-07-27T22:12:40.382Z"),
"lastHeartbeatRecv" : ISODate("2017-07-27T22:12:41.213Z"),
"pingMs" : 0,
"configVersion" : 1
},
{
"_id" : 2,
"name" : "192.168.80.128:27022",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1090,
"optime" : Timestamp(1501192872, 1),
"optimeDate" : ISODate("2017-07-27T22:01:12Z"),
"configVersion" : 1,
"self" : true
},
{
"_id" : 3,
"name" : "192.168.80.128:27023",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 688,
"optime" : Timestamp(1501192872, 1),
"optimeDate" : ISODate("2017-07-27T22:01:12Z"),
"lastHeartbeat" : ISODate("2017-07-27T22:12:39.673Z"),
"lastHeartbeatRecv" : ISODate("2017-07-27T22:12:39.820Z"),
"pingMs" : 0,
"electionTime" : Timestamp(1501193266, 1),
"electionDate" : ISODate("2017-07-27T22:07:46Z"),
"configVersion" : 1
}
],
"ok" : 1
}```

五、增加、删除节点

1.cp -r node8 node10，修改node10的datapath、logpath的port，并将port 改为 27024，启动 node10。

2.进入到主节点中，mongo --host 192.168.80.128 --port 27023，一定要在主节点中进行操作。

3.增加节点：rs.add(“192.168.80.128:27024”)

>XbqSet:PRIMARY> rs.add("192.168.80.128:27024")
{ "ok" : 1 }

4.查看状态，rs.status()，发现新增加的节点 为从节点，即 SECONDARY。

XbqSet:PRIMARY> rs.status()
{
"set" : "XbqSet",
"date" : ISODate("2017-07-29T14:31:44.872Z"),
"myState" : 1,
"members" : [
{
"_id" : 1,
"name" : "192.168.80.128:27021",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 630,
"optime" : Timestamp(1501338697, 1),
"optimeDate" : ISODate("2017-07-29T14:31:37Z"),
"lastHeartbeat" : ISODate("2017-07-29T14:31:43.555Z"),
"lastHeartbeatRecv" : ISODate("2017-07-29T14:31:43.457Z"),
"pingMs" : 0,
"configVersion" : 2
},
{
"_id" : 2,
"name" : "192.168.80.128:27022",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1854,
"optime" : Timestamp(1501338697, 1),
"optimeDate" : ISODate("2017-07-29T14:31:37Z"),
"lastHeartbeat" : ISODate("2017-07-29T14:31:43.555Z"),
"lastHeartbeatRecv" : ISODate("2017-07-29T14:31:43.186Z"),
"pingMs" : 0,
"configVersion" : 2
},
{
"_id" : 3,
"name" : "192.168.80.128:27023",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 1953,
"optime" : Timestamp(1501338697, 1),
"optimeDate" : ISODate("2017-07-29T14:31:37Z"),
"electionTime" : Timestamp(1501338022, 1),
"electionDate" : ISODate("2017-07-29T14:20:22Z"),
"configVersion" : 2,
"self" : true
},
{
"_id" : 4,
"name" : "192.168.80.128:27024",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 7,
"optime" : Timestamp(1501338697, 1),
"optimeDate" : ISODate("2017-07-29T14:31:37Z"),
"lastHeartbeat" : ISODate("2017-07-29T14:31:43.566Z"),
"lastHeartbeatRecv" : ISODate("2017-07-29T14:31:43.579Z"),
"pingMs" : 6,
"configVersion" : 2
}
],
"ok" : 1
}

5.删除节点：rs.remove(hostportstr)

XbqSet:PRIMARY> rs.remove("192.168.80.128:27024")
{ "ok" : 1 }

查看状态，发现 端口为27024的节点 没有了。