Error when try to connect to Replica Set in Mongo - mongodb

Question

When I try to connect to mongo replica set in AWS I get this error:
slavenode:27017: [Errno -2] Name or service not
known,ip-XXX-XX-XX-XX:27017: [Errno -2] Name or service not known
(where XXX-XX.. corresponds to my actual ip address)
The code to connect is shown below:
client = MongoClient("mongodb://Master-PublicIP:27017,Slave-PublicIP:27017/myFirstDB?replicaSet=rs0")
db = client.myFirstDB
try:
db.command("serverStatus")
except Exception as e:
print(e)
else:
print("You are connected!")
client.close()
(where in Master-PublicIP and Slave-PublicIP I have the actual IPv4 Public IP's from AWS console)
I have already a replica set and the configuration is:
rs0:PRIMARY> rs.conf()
{
"_id" : "rs0",
"version" : 2,
"members" : [
{
"_id" : 0,
"host" : "ip-XXX-XX-XX-XXX:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slaveDelay" : 0,
"votes" : 1
},
{
"_id" : 1,
"host" : "SlaveNode:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slaveDelay" : 0,
"votes" : 1
}
],
"settings" : {
"chainingAllowed" : true,
"heartbeatTimeoutSecs" : 10,
"getLastErrorModes" : {
},
"getLastErrorDefaults" : {
"w" : 1,
"wtimeout" : 0
}
}
}
I have create the /data/db in PRIMARY and the /data/db1 in SECONDARY and I have give the proper ownership with sudo chmod -R 755 /data/db
My MongoDB version is 3.0.15. Is anyone know what is going wrong?
Thanks in advance.

Answer 1

Have you tried removing the myFirstDB from within the MongoClient()
MongoClient("mongodb://Master-PublicIP:27017,Slave-PublicIP:27017/?replicaSet=rs0")
Because your next line then specifies which db you want to use
db = client.myFirstDB
Or I think you can specify the db by putting a dot after the closing brace on the MongoClient()
MongoClient("mongodb://Master-PublicIP:27017,Slave-PublicIP:27017/?replicaSet=rs0").myFirstDB

Answer 2

I manage to solve the problem. As #N3i1 suggests in commnets, I use the Public DNS (IPv4). There was an issue with the hosts that I had declare in /etc/hosts.
In this file I had define the ips of master/ slaves with some names. For some reason this didn't work. I delete them and then I reconfigure the replica set configuration.
In PRIMARY in mongo shell I did:
cfg = {"_id" : "rs0", "members" : [{"_id" : 0,"host" : "Public DNS (IPv4):27017"},{"_id" : 1,"host" : "Public DNS (IPv4):27017"}]}
rs.reconfig(cfg,{force: true});
Then I connect in the replica set with python with:
MongoClient("mongodb://Public DNS (IPv4):27017,Public DNS (IPv4):27017/?replicaSet=rs0")
Of course change the Public DNS (IPv4) adresses with yours.