Below is the error I get if I start mongo shell and try to see which dbs are there, tried using both bitnami as well as ubuntu as users, also what is root pwd for bitnami root user so i can try using that as well.
MongoDB shell version v3.4.2
connecting to: mongodb:///opt/bitnami/mongodb/tmp/mongodb-27017.sock/
MongoDB server version: 3.4.2
> show dbs;
2017-11-08T07:14:01.123+0000 E QUERY [thread1] Error: listDatabases
failed:{
"ok" : 0,
"errmsg" : "not authorized on admin to execute command {
listDatabases: 1.0 }",
"code" : 13,
"codeName" : "Unauthorized"
} :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
Mongo.prototype.getDBs@src/mongo/shell/mongo.js:62:1
shellHelper.show@src/mongo/shell/utils.js:755:19
shellHelper@src/mongo/shell/utils.js:645:15
@(shellhelp2):1:1