In Compass, network related issues manifest in so many ways that it is hard to keep it out of the consideration when debugging any issue and it is always preferred to make sure that at least these two basics tests are passing before going any further.
27017 is the port number on which the clusters are running. All the nodes in the Cluster0-shard-0 replica set which we use in our M001 : MongoDB Basics course runs on the same port i.e. 27017.
You can easily verify this by connecting to the cluster from the mongo shell and then running the command
Yes, this is correct that the secondaries will not serve the read requests if the
slaveOk property for the current connection has been set to false but for this replica set it does not apply because this property has been set to true and read from secondaries are permissible.
In your connection string if you have included the name of the replica set along with any of its members host and port address, you should not worry about which node is the primary because it will always connect you to the primary.
In this screenshot, I can see that the replica set name has been provided so which node is the primary is not of any concern here.
Yes, the primary nodes keeps on changing from time to time due to some very obvious reasons. The thread that you are referring to here was for one of our student’s sandbox cluster.
You can totally connect to the atlas class cluster using the SRV Records as it has been already configured for the same. For doing that please use the connection string mentioned below and select the SRV Record option.
Hope it helps. BTW, I like your debugging style and your engagement with the community. Keep up the good work
Curriculum Support Engineer