root cant perform listCollections command on db

Question

I have credentials for root user and I am using those credentials to automate db backup. Main aim is to create prototype for Automated DB backup and, for simplicity, I am using root. The script (I borrowed from article) looks like as follows:

#!/bin/bash

#Force file syncronization and lock writes
mongo admin -u "root" -p "root" --eval "printjson(db.fsyncLock())"

MONGODUMP_PATH="/usr/bin/mongodump"
MONGO_DATABASE="mydb" #replace with your database name

TIMESTAMP=`date +%F-%H%M`
S3_BUCKET_NAME="mydb" #replace with your bucket name on Amazon S3
S3_BUCKET_PATH="backup/mongo"

# Create backup
$MONGODUMP_PATH -d $MONGO_DATABASE

# Add timestamp to backup
mv dump mongodb-$HOSTNAME-$TIMESTAMP
tar cf mongodb-$HOSTNAME-$TIMESTAMP.tar mongodb-$HOSTNAME-$TIMESTAMP

# Upload to S3
s3cmd put mongodb-$HOSTNAME-$TIMESTAMP.tar s3://$S3_BUCKET_NAME/$S3_BUCKET_PATH/mongodb-$HOSTNAME-$TIMESTAMP.tar

#Unlock database writes
mongo admin -u "root" -p "root" --eval "printjson(db.fsyncUnlock())"
#Delete local files
#rm -rf mongodb-*

I am getting following error:

Failed: error getting collections for database mydb: error running listCollections. Database: mydb Err: not authorized on mydb to execute command { listCollections: 1, cursor: {} }

Isnt root has all the access over all the databases? I am bit scared that I might run into situation where I am thinking to supersede something with root but It doesnt have the permission. This is the root cause of posting question. I want to avoid surprises like this in the future.

Answer 1

The error mentioned above was misleading for me. But my script was wrong or incomplete.

If you look at following line in my script:

$MONGODUMP_PATH -d $MONGO_DATABASE

I am not providing any user in Mongodump command and hence the error message. If I rewrite that line something as follows:

$MONGODUMP_PATH -d $MONGO_DATABASE --authenticationDatabase "admin" -u "dbowner" -p "pwd"

then error goes away.