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NFS server edits: (#1342)
* Create nfsserver.md (#1335) * Create nfsserver.md Documentation about nfsserver * Apply suggestions from code review Thx @serge Co-authored-by: Serge Croisé <[email protected]> * Update docs/guides/file_sharing/nfsserver.md Those darn spaces! Co-authored-by: Serge Croisé <[email protected]> * Update docs/guides/file_sharing/nfsserver.md Co-authored-by: Serge Croisé <[email protected]> * Update docs/guides/file_sharing/nfsserver.md wording change Co-authored-by: Serge Croisé <[email protected]> * Update nfsserver.md --------- Co-authored-by: Serge Croisé <[email protected]> Co-authored-by: sspencerwire <[email protected]> Co-authored-by: wale soyinka <[email protected]> * NFS server edits: * remove most (not all) passive voice * remove punctuation on bullet points except those under "Case studies" which are a command parameters with a qualifying sentence. * some minor wording changes for better understanding (for instance "conserved" becomes "preserves") * added Serge to contributors * Update nfsserver.md Some changes not saved... edited to put them back in. * Update docs/guides/file_sharing/nfsserver.md Co-authored-by: Serge Croisé <[email protected]> --------- Co-authored-by: Antoine Le Morvan <[email protected]> Co-authored-by: Serge Croisé <[email protected]> Co-authored-by: wale soyinka <[email protected]>
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‎docs/guides/file_sharing/nfsserver.md‎

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---
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title: Network File System
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author: Antoine Le Morvan
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contributors: Steven Spencer, Serge
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---
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# Network File System
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**Knowledge**: :star: :star:
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**Complexity**: :star: :star:
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**Reading time**: 15 minutes
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**N**etwork **F**ile **S**ystem (**NFS**) is a network-mounted file-sharing system.
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## Generalities
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NFS is a client/server protocol: the server provides file system resources for all or part of the network (clients).
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The communication between clients and server takes place by way of **R**emote **P**rocedure **C**all (**RPC**) services.
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Remote files are mounted in a directory and appear as a local file system. Client users seamlessly access files shared by the server, browsing directories as if they were local.
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## Installation
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NFS requires two services to function:
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* The `network` service (of course)
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* The `rpcbind` service
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View the status of the services with the command:
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```
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systemctl status rpcbind
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```
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If the `nfs-utils` package is not installed:
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```
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sudo dnf install nfs-utils
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```
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The `nfs-utils` package requires the installation of several dependencies, including `rpcbind`.
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Start the NFS service with:
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```
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sudo systemctl enable --now nfs-server rpcbind
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```
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Installing the NFS service creates two users:
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* `nobody`: used for anonymous connections
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* `rpcuser`: for RPC protocol operation
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Configuring the firewall is necessary:
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```
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sudo firewall-cmd --add-service={nfs,nfs3,mountd,rpc-bind} --permanent
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sudo firewall-cmd --reload
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```
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## Server configuration
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!!! warning "warning"
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Directory rights and NFS rights must be consistent.
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### The `/etc/exports` file
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Set up resource shares with the `/etc/exports` file. Each line in this file corresponds to an NFS share.
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```
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/share_name client1(permissions) client2(permissions)
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```
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* **/share_name**: Absolute path of shared directory
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* **clients**: Clients authorized to access resources
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* **(permissions)**: Permissions on resources
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Declare machines authorized to access resources with:
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* **IP address**: `192.168.1.2`
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* **Network address**: `192.168.1.0/255.255.255.0` or CIDR format `192.168.1.0/24`
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* **FQDN**: client_*.rockylinux.org: allows FQDNs starting with client_ from the rockylinux.org domain
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* `*` for everybody
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Specification of multiple clients is possible on the same line separated by a space.
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### Permissions on resources
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There are two types of permissions:
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* `ro`: read-only
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* `rw`: read-write
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If no right is specified, then the right applied will be read-only.
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By default, the NFS server preserves the client user UIDs and GIDs (except for `root`).
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To force the use of a UID or GID other than that of the user writing the resource, specify the `anonuid=UID` and `anongid=GID` options, or give `anonymous` access to the data with the `all_squash` option.
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!!! warning "warning"
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There is a parameter, `no_root_squash`, which identifies the client root user as the server root user. This parameter can be dangerous from a system security point of view.
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Activation of the `root_squash` parameter is a default (even if not specified), identifying `root` as an `anonymous` user.
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### Case studies
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* `/share client(ro,all_squash)`
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Client users have read-only access to resources and are identified as anonymous on the server.
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* `/share client(rw)`
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Client users can modify resources and keep their UID on the server. Only `root` is identified as `anonymous`.
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* `/share client1(rw) client2(ro)`
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Users on client workstation 1 can modify resources, while those on client workstation 2 have read-only access.
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UIDs are kept on the server, and only `root` is identified as `anonymous`.
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* `/share client(rw,all_squash,anonuid=1001,anongid=100)`
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Client1 users can modify resources. Their UID is changed to `1001` and their GID to `100` on the server.
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### The `exportfs` command
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The `exportfs` (exported file systems) command is used to manage the table of local files shared with NFS clients.
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```
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exportfs [-a] [-r] [-u share_name] [-v]
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```
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| Options | Description |
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| --------------- | ----------------------------------------- |
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| `-a` | Enables NFS shares |
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| `-r` | Applies shares from the `/etc/exports` file |
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| `-u share_name` | Disables a given share |
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| `-v` | Displays the list of shares |
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### The `showmount` command
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Use the `showmount` command to monitor clients.
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```
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showmount [-a] [-e] [host]
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```
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| Options | Description |
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| ------- | ----------------------------------------- |
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| `-e` | Displays shares on the designated server |
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| `-a` | Displays all current shares on the server |
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This command also determines whether the client workstation has authorization to mount shared resources.
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!!! note "note"
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`showmount` sorts and hides duplicates in the results, so it's impossible to determine whether a client has made multiple mounts of the same directory or not.
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## Client configuration
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Shared resources on an NFS server are accessible through a mount point on the client.
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If required, create a local folder for mounting:
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```
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$ sudo mkdir /mnt/nfs
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```
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List available NFS shares on the server:
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```
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$ showmount –e 172.16.1.10
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/share *
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```
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Mount the server's NFS share:
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```
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$ mount –t nfs 172.16.1.10:/share /mnt/nfs
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```
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Automation of the mount can happen at system startup with the `/etc/fstab` file:
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```
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$ sudo vim /etc/fstab
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172.16.1.10:/share /mnt/nfs nfs defaults 0 0
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```

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