OPS335: File Servers

FILE SERVER RESOURCES

Online References:

OVERVIEW

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INVESTIGATION 1: NETWORK FILE SERVER (NFS)

In this lab you'll set up a Fedora VM as an NFS (Network File System) server. Then you'll set up the other VMs as NFS clients that will import their /home directories from this NFS server.

Prerequisites
Before you begin make sure your virtual machines are up to date.

Ensure all machines are using the firewalls you created in previous labs.
Ensure both host and VM's have firewalls set up according to prior labs. And ensure you are using your seneca account (the first user created - this will be

critical for success)

Setting up the NFS Server

On your VM 2 machine perform the following tasks:

• You do not need to install nfs, as it is present by default on the server installation of Fedora 22. If it is not there use the following command:

dnf install nfs-utils

• edit /etc/exports so that it contains ONLY the following line (where 192.168.x.4 is the IP address of your guest VM):

 /home 192.168.x.4(rw,root_squash,insecure)

• Start enable your nfs service (now known as nfs-server.service).
• Build the server's list of exports

 exportfs -r

• Run and record the output of the following commands:

exportfs
showmount -e

NOTE: You'll have to adjust your firewall on VM2 to get NFS to work. Run netstat to determine the ports needed.

Read about NFS security here.

Setting up the NFS Client

Configuring the NFS client

• Ensure the VM guest network is functioning properly. You can use the "host cbc.ca" command to see if DNS queries are being answered.
• Ensure you have full connectivity to the internet.
• Again, you should not have to install any NFS software.
• Add the following line to the bottom of the /etc/fstab file on vm03

192.168.x.3:/home  	/home	nfs4	defaults	0 0

Warning:
Do not change any other lines in this file. Do not change any lines in /etc/fstab on your host machine. Doing so can make your machine fail to boot.

• Run the following command to avoid an error that would be caused by logging in while root_squash is active:

setsebool -P use_nfs_home_dirs 1

• Logout of vm03 and shut it down.

Testing NFS mounts on your client

• Restart vm03 and login using your learnid.

• Check that the home directory is mounted

mount | grep /home

• If it is not, try running 'mount /home' as root and observe any errors.
• On vm03, create an empty file using the touch command.

touch empty_file_created_on_vm03

• Now shutdown vm03.
• Now on the NFS server, us ls -l in your learnid's home directory to check for the file you just created.

Setting up Automount on the VM

On vm03 as root perform the following tasks:

• Comment or remove the line from /etc/fstab that you entered earlier.
• With a server installation of Fedora 22, you will not need to install autofs, but on other installations you might need:

dnf install autofs

• Move the existing file /etc/auto.master:

mv /etc/auto.master /etc/auto.master.orig

• This is a great way to keep a back up in case you need to restore the file in the future. Now create another:

vi /etc/auto.master

• Add only the following line:

/home   /etc/auto.home   --timeout=60

• Create the file /etc/auto.home and add ONLY the following line:

*        -fstype=nfs4,rw,nosuid,soft      192.168.x.3:/home/&

• Start autofs, and ensure the service will automatically start at boot.

• Log out of vm3 and log back in using your learn account.
• Open a terminal and enter the command:

mount | grep home

• How does it differ from the previous mount?
• Create another empty file with the name

touch another_empty_file_from_vm03

• Run and record the output of the command

df -hT

• Back on the nfs server run and record the output of ls -l in your home directory.
• You should see the files you created on vm03.
• You may encounter errors with SELinux during the lab (though it has not been a problem recently). It is required that you leave it running. Use the following commands to determine what booleans need to be flipped.

audit2allow < /var/log/audit/audit.log
audit2why < /var/log/audit/audit.log

Setting up Automount on the other VM

• Now that you have VM3 automatically mounting home directories from VM2, configure VM1 to do the same.

Record steps, commands, and your observations in INVESTIGATION 1 in your OPS335 lab log-book

COMPLETING THE LAB

Arrange proof that ...

EXPLORATION QUESTIONS

1. What does the no_root_squash option for an NFS mount mean?
2. Explain the meaning of the defaults option in an fstab entry. What do the numbers mean at the end?
3. What is the function of the 'exportfs' command?
4. What is the purpose of the 'showmount' command?
5. What is the meaning of the "timeout=60" phrase?
6. What is the meaning of the asterisk (*) in the file /etc/auto.home?
7. What is the meaning of the ampersand (&) in the file /etc/auto.home?
8. What is the role of the /etc/mtab file on the nfs server?
9. What port does nfs-server use?