`ServerSelectionTimeoutError` on Dockerized Mongodb Replica Set

I’m trying to use Docker locally to test out mongo-connector but with no luck so far.

It works fine when connecting to a local mongod instance (i.e. just running mongod --replSet singleNodeRepl in terminal), but in Docker I get this error:

ServerSelectionTimeoutError: Could not reach any servers in [(u'344da2f17060', 27017)]. Replica set is configured with internal hostnames or IPs?

For some reason, the IP address of the replica set member inside the Docker container is a hex string: 344da2f17060.

Any way to make this work in Docker?

Following the instructions here, I created a replica set in a docker container (i.e. docker run mongo mongod --replSet singleNodeRepl), executed rs.initiate() from its mongo shell, loaded it up with some data and ran mongo-connector like so: mongo-connector -c mongo-connector-config.json -m 192.168.99.100:27017 -t 192.168.99.100:9200 -d elastic_doc_manager

The config only contains namespaces.

[vancouverwill]

to get this to work on mac (osx has weird config with docker) with locally hosted mongo and mongo-connector in docker we had to add to our mac’s hosts file

127.0.0.1 host.docker.internal

Then we updated replica set as stated above so

cfg.members[0].host = "host.docker.internal:27017"

This worked good for us

[robertaistleitner]

I have the same issue, also using docker containers. The fix with localhost:27017 doesn’t solve the problem for me, because mongo-connector is running in a different container and hast no idea where localhost:27017 is…

I think the only solution is to use host names which can be resolved by

1. the server where mongodb itself is running on, as well as
2. the server where mongo-connector is running on

because otherwise host name resolution will fail from pymongo library.

This solved the problem for me…