Why is an rw EFS mounted on EC2 not allowing file or folder creation?

Question

I created an EFS and mounted it on a free tier Amazon Linux 2 AMI (HVM) EC2 instance. I'm able to SSH into the EC2 instance, and I can navigate into `/mnt/efs/fs1`. However, when I do an `mkdir abc` in the `/mnt/efs/fs1` folder, I get the error `mkdir: cannot create directory ‘abc’: Permission denied`.  
If I run `mount -t nfs4`, I get the output:  
_127.0.0.1:/ on /mnt/efs/fs1 type nfs4 (rw,relatime,vers=4.1,rsize=1048576,wsize=1048576,namlen=255,hard,noresvport,proto=tcp,port=20240,timeo=600,retrans=2,sec=sys,clientaddr=127.0.0.1,local_lock=none,addr=127.0.0.1,_netdev)_  
  
I've seen a page about the AWS transfer family, but the steps aren't clear and it looks like it's not meant for the purpose I need it for. I basically need to create a few folders in EFS and copy some files from my PC to those folders on EFS. Since AWS does not provide a drag-and-drop option like Google Drive, I'm having to use SSH. But I'm not even able to create a directory on the mounted folder.   
Please help.

Accepted Answer

It's possible that you are trying to create the directory as a non-root user, while /mnt/efs/fs1 is owned by root.  
  
Please see https://docs.aws.amazon.com/efs/latest/ug/accessing-fs-nfs-permissions.html - you can either change the permissions on your directory as root (with sudo) or use an access point.

Answer

If you want to create a folder inside the EFS volume that is owned by a user on the EC2 instance, you could do the following (assuming you are logged in as ec2-user):

1. cd /mnt/efs/fs1
2. sudo mkdir your-folder-name
3. chown -R ec2-user:ec2-user your-folder-name

This will use root privileges to create new folder within the EFS volume and then assign ownership to another user, in this case the default ec2-user that you will get when you create an EC2 instance using Amazon Linux 2.

Why is an rw EFS mounted on EC2 not allowing file or folder creation?

관련 콘텐츠