Windows users: NFS folders do not work on Windows
hosts. Vagrant will ignore your request for NFS synced folders on
Windows.
## Prerequisites
Before using synced folders backed by NFS, the host machine must have
`nfsd` installed, the NFS server daemon. This comes pre-installed on Mac
OS X, and is typically a simple package install on Linux.
Additionally, the guest machine must have NFS support installed. This is
also usually a simple package installation away.
If you're using the VirtualBox provider, you'll also need to make sure you
have a
[private network set up](http://docs.vagrantup.com/v2/networking/private_network.html). This is due to a limitation of VirtualBox's built-in networking. With
VMware, you do not need this.
## Enabling NFS Synced Folders
To enable NFS, just add the `type: "nfs"` flag onto your synced folder:
```ruby
Vagrant.configure("2") do |config|
# ...
config.vm.synced_folder ".", "/vagrant", type: "nfs"
end
```
If you add this to an existing Vagrantfile that has a running guest machine,
be sure to `vagrant reload` to see your changes.
## NFS Synced Folder Options
NFS synced folders have a set of options that can be specified that are
unique to NFS. These are listed below. These options can be specified in
the final part of the `config.vm.synced_folder` definition, along with the
`type` option.
* `nfs_export` (boolean) - If this is false, then Vagrant won't modify
your `/etc/exports` automatically and assumes you've done so already.
* `nfs_udp` (boolean) - Whether or not to use UDP as the transport. UDP
is faster but has some limitations (see the NFS documentation for more
details). This defaults to true.
* `nfs_version` (string | integer) - The NFS protocol version to use when
mounting the folder on the guest. This defaults to 3.
## NFS Global Options
There are also more global NFS options you can set with `config.nfs` in
the Vagrantfile. These are documented below:
* `functional` (bool) - Defaults to true. If false, then NFS won't be used
as a synced folder type. If a synced folder specifically requests NFS,
it will error.
* `map_uid` and `map_gid` (int) - The UID/GID, respectively, to map all
read/write requests too. This will not affect the owner/group within the
guest machine itself, but any writes will behave as if they were written
as this UID/GID on the host. This defaults to the current user running
Vagrant.
* `verify_installed` (bool) - Defaults to true. If this is false, then
Vagrant will skip checking if NFS is installed.
## Specifying NFS Arguments
In addition to the options specified above, it is possible for Vagrant to
specify alternate NFS arguments when mounting the NFS share by using the
`mount_options` key. For example, to use the `actimeo=2` client mount option:
```
config.vm.synced_folder ".", "/vagrant",
:nfs => true,
:mount_options => ['actimeo=2']
```
This would result in the following `mount` command being executed on the guest:
```
mount -o 'actimeo=2' 172.28.128.1:'/path/to/vagrantfile' /vagrant
```
You can also tweak the arguments specified in the `/etc/exports` template
when the mount is added, by using the OS-specific `linux__nfs_options` or
`bsd__nfs_options` keys. Note that these options completely override the default
arguments that are added by Vagrant automatically. For example, to make the
NFS share asynchronous:
```
config.vm.synced_folder ".", "/vagrant",
:nfs => true,
:linux__nfs_options => ['rw','no_subtree_check','all_squash','async']
```
This would result in the following content in `/etc/exports` on the host (note
the added `async` flag):
```
# VAGRANT-BEGIN: 21171 5b8f0135-9e73-4166-9bfd-ac43d5f14261
"/path/to/vagrantfile" 172.28.128.5(rw,no_subtree_check,all_squash,async,anonuid=21171,anongid=660,fsid=3382034405)
# VAGRANT-END: 21171 5b8f0135-9e73-4166-9bfd-ac43d5f14261
```
## Root Privilege Requirement
To configure NFS, Vagrant must modify system files on the host. Therefore,
at some point during the `vagrant up` sequence, you may be prompted for
administrative privileges (via the typical `sudo` program). These
privileges are used to modify `/etc/exports` as well as to start and
stop the NFS server daemon.
If you don't want to type your password on every `vagrant up`, Vagrant
uses thoughtfully crafted commands to make fine-grained sudoers modifications
possible to avoid entering your password.
Below, we have a couple example sudoers entries. Note that you may
have to modify them _slightly_ on certain hosts because the way Vagrant
modifies `/etc/exports` changes a bit from OS to OS.
For OS X, sudoers should have this entry:
```
Cmnd_Alias VAGRANT_EXPORTS_ADD = /usr/bin/tee -a /etc/exports
Cmnd_Alias VAGRANT_NFSD = /sbin/nfsd restart
Cmnd_Alias VAGRANT_EXPORTS_REMOVE = /usr/bin/sed -E -e /*/ d -ibak /etc/exports
%admin ALL=(root) NOPASSWD: VAGRANT_EXPORTS_ADD, VAGRANT_NFSD, VAGRANT_EXPORTS_REMOVE
```
For Ubuntu Linux , sudoers should look like this:
```
Cmnd_Alias VAGRANT_EXPORTS_ADD = /usr/bin/tee -a /etc/exports
Cmnd_Alias VAGRANT_NFSD_CHECK = /etc/init.d/nfs-kernel-server status
Cmnd_Alias VAGRANT_NFSD_START = /etc/init.d/nfs-kernel-server start
Cmnd_Alias VAGRANT_NFSD_APPLY = /usr/sbin/exportfs -ar
Cmnd_Alias VAGRANT_EXPORTS_REMOVE = /bin/sed -r -e * d -ibak /etc/exports
%sudo ALL=(root) NOPASSWD: VAGRANT_EXPORTS_ADD, VAGRANT_NFSD_CHECK, VAGRANT_NFSD_START, VAGRANT_NFSD_APPLY, VAGRANT_EXPORTS_REMOVE
```
For Fedora Linux, sudoers might look like this (given your user
belongs to the vagrant group):
```
Cmnd_Alias VAGRANT_EXPORTS_ADD = /usr/bin/tee -a /etc/exports
Cmnd_Alias VAGRANT_NFSD_CHECK = /usr/bin/systemctl status nfs-server.service
Cmnd_Alias VAGRANT_NFSD_START = /usr/bin/systemctl start nfs-server.service
Cmnd_Alias VAGRANT_NFSD_APPLY = /usr/sbin/exportfs -ar
Cmnd_Alias VAGRANT_EXPORTS_REMOVE = /bin/sed -r -e * d -ibak /etc/exports
%vagrant ALL=(root) NOPASSWD: VAGRANT_EXPORTS_ADD, VAGRANT_NFSD_CHECK, VAGRANT_NFSD_START, VAGRANT_NFSD_APPLY, VAGRANT_EXPORTS_REMOVE
```
## Other Notes
**Encrypted folders:** If you have an encrypted disk, then NFS very often
will refuse to export the filesystem. The error message given by NFS is
often not clear. One error message seen is `