Mongodump from secure Mongo database - mongodb

Question

In order for me to connect to this [secure] Mongo instance I have to run the following command:
mongo --ssl --host sampleHostname --sslPEMKeyFile /path/to/user.pem --sslCAFile /path/to/mongoca.cer --authenticationDatabase '$external' --authenticationMechanism=MONGODB-X509
I am trying to do a mongodump command to get the data but I keep running into the following errors:
Attempt 1
mongodump -d mydb
Failed: error connecting to db server: no reachable servers
Attempt 2
Can't create backup mongodump with --db. Authentication failed
mongodump -d mydb --authenticationDatabse '$external'
Failed: error connecting to db server: no reachable servers
Attempt 3 Using the same command as how I connect.
mongodump -d mydb --ssl --host sampleHostname --sslPEMKeyFile /path/to/user.pem --sslCAFile /path/to/mongoca.cer --authenticationDatabase '$external' --authenticationMechanism=MONGODB-X509
Failed: error getting collections for database 'mydb': error running 'listCollections'. Database: 'mydb' Err: not authorized on 'mydb' to execute command {listCollections: 1, cursor: {} }
I have tried the same command with sudo but it still returns the same error.
Attempt 4 Minimum permission for using mongodump (to dump a specific db)
mongodump -d mydb --ssl --host sampleHostname --sslPEMKeyFile /path/to/user.pem --sslCAFile /path/to/mongoca.cer --authenticationDatabase '$external' --authenticationMechanism=MONGODB-X509 --excludeCollection=system.indexes
Failed: error getting collections for database 'mydb': error running 'listCollections'. Database: 'mydb' Err: not authorized on 'mydb' to execute command {listCollections: 1, cursor: {} }
I am stuck and I am eventually going to run mongorestore but I do not want to run this without making sure I am able to backup first. I imagine the solution for mongodump will resolve any possible issues I may have with mongorestore (if any).

Answer 1

I found the solution thanks to this blog post , looks you have to set the -u value with the CN when using 509 and $external.
mongodump --ssl --sslPEMKeyFile user.pem --sslCAFile cap.pem --sslAllowInvalidHostnames --authenticationMechanism=MONGODB-X509 --authenticationDatabase '$external' --host "rsTmpCloudManager/10.100.15.118:27017,10.100.16.237:27017,10.100.17.107:27017" -d testJoce -u "CN=???,OU=???,O=???,L=???,ST=???,C=??"