Skip to main content
Instead of mounting NFS shares permanently at boot — which can slow startup or cause the system to hang if the NFS server is unavailable — use autofs for service-based, on-demand mounts. autofs is an automounter daemon that mounts filesystems only when they are accessed (on-demand), rather than at boot. This makes NFS mounts more reliable and fault-tolerant: a down NFS server will not block or delay system startup because autofs attempts mounts only when a user or process accesses the mount point.
A dark-themed slide titled "Autofs" showing a central card labeled "autofs" with three blue gradient circles above it and two rounded info boxes reading "Service-based Automounter" and "Automatically mounts filesystems when accessed." A gear icon and an exclamation mark are visible near the bottom.
This guide uses the example NFS server 10.0.2.15 exporting under /srv/nfs/. Replace the IP and export paths to match your environment. These examples assume a RHEL-like system (CentOS, Fedora, Rocky, Alma).

​
What you’ll configure

  • Install and enable the autofs service.
  • Create a master map file (/etc/auto.master.d/master.autofs) that references:
    • a direct map (/etc/auto.direct), and
    • an indirect map (/etc/auto.indirect).
  • Test that NFS exports are mounted on-demand when accessed.

​
Installation and enabling the autofs service

Install autofs:
Enable and start autofs (use --now to enable and start in one step):
Sample status output:

​
Configuring the autofs master file and maps

autofs uses a master map that points to one or more map files. Modern RHEL-like distributions allow dropping files with the .autofs suffix into /etc/auto.master.d/. Create a file /etc/auto.master.d/master.autofs that tells autofs where to find the direct and indirect maps. Create /etc/auto.master.d/master.autofs:
  • /- (direct map) means each key in /etc/auto.direct is a full absolute path to be mounted.
  • /indirect (indirect map) means subdirectories under /indirect are created on-demand according to keys found in /etc/auto.indirect.

​
Direct map: absolute mount points

Create /etc/auto.direct. Direct maps use absolute mount points. Example: mount the export 10.0.2.15:/srv/nfs/share at /auto-direct:
  • The left column is the absolute mount point.
  • The middle field lists mount options (-rw,sync).
  • The right side is the NFS server export.

​
Indirect map: keyed subdirectories under a parent

Create /etc/auto.indirect. Indirect maps use keys that become subdirectories under the parent (/indirect in the master file). Using a wildcard allows matching multiple keys:
  • * matches any subdirectory name under /indirect.
  • & expands to the matched key, so accessing /indirect/central mounts 10.0.2.15:/srv/nfs/share/autofs-indirect/central.
Restart autofs to apply configuration:

​
Quick reference: map files

​
Testing the automounts

After restarting autofs, autofs creates the mount-point directories even before the NFS mounts occur. Verify the directories exist:
Direct map behavior: accessing the absolute mount point triggers a mount:
Indirect map behavior: the parent directory may appear empty until a keyed subdirectory is accessed. Accessing a keyed subdirectory triggers autofs to mount only that export:
Each subdirectory under /indirect is mounted individually and on-demand when first accessed. For example, accessing /indirect/east will mount 10.0.2.15:/srv/nfs/share/autofs-indirect/east. This on-demand mount behavior avoids slow or stalled boots caused by unreachable network shares.
If the NFS server is unreachable, autofs will not block boot; however, processes that try to access a missing mount point will hang until the mount times out or the server becomes available. Ensure NFS server accessibility, firewall rules, and SELinux contexts are correct for your environment.

​
Troubleshooting tips

  • Confirm the NFS server and exported paths are reachable: showmount -e 10.0.2.15.
  • Check journalctl -u autofs for autofs-specific logs and errors.
  • If mounts fail, verify NFS client packages (nfs-utils) are installed and that the firewall allows NFS traffic.
  • For SELinux-denied mounts, inspect ausearch or audit.log and apply required boolean / context fixes.

​
Summary

You have configured autofs to manage both direct and indirect NFS automounts:
  • Installed and enabled the autofs service.
  • Created a master map file (/etc/auto.master.d/master.autofs) referencing a direct map (/etc/auto.direct) and an indirect map (/etc/auto.indirect).
  • Used direct maps for absolute mount points and indirect maps for keyed on-demand subdirectories with wildcard matching and & substitution.
  • Verified that NFS exports are mounted only when accessed, improving boot reliability and reducing dependency on network availability.
By using autofs, systems relying on network-attached storage can avoid slow or stalled boot behavior caused by static NFS mounts.
A dark-themed slide or interface with the word "Summary" on the left and a panel on the right listing storage-related topics. Items include "Basic storage," "Managing Swap Space," "Logical Volumes," and "Working with Network Attached Storage."

Watch Video

Practice Lab