EFS NFS POSIX Permissions

Question

Hello,

I've been exploring the topic of EFS NFS POSIX Permissions and came across information about the supported identities (root, user, and groups) in POSIX. I'm curious about how the root user is defined within the EFS file system. Is it determined by the AWS User who creates the file system, or is it associated with the EC2 instance that initially mounts the file system?

Furthermore, I'm interested in understanding who the users are. Are they other AWS users, or are they associated with other EC2 instances?

I appreciate any insights you can provide. Thank you!

Accepted Answer

By default, Amazon EFS uses root squashing, a common NFS feature. This means that when the root user of an NFS client accesses the EFS file system, their UID and GID are automatically mapped to the "nobody" user and group (typically UID/GID 65534), effectively stripping the elevated privileges. This behavior can be modified with custom NFS client mount options if root access is necessary.

The root user and other user identities within Amazon EFS are defined by the UID and GID of the operating systems on the client machines that mount the EFS file system. They are not determined by AWS users or directly associated with the AWS account that creates the file system. Managing access and permissions effectively requires careful configuration of these identities on your EC2 instances or other NFS clients that access EFS.

EFS NFS POSIX Permissions

Relevant content