If 4 drives are available use RAID 10, if 2 drives use RAID 1.

Create 2GB /boot standard partition on xfs (should be on a hardware R10, R1 or software R1)

Note: if using a software R1, install grub2 on both drives that will participate in the R1 array or the R1 part of the R10 array. (grub2-install /dev/sda and grub2-install /dev/sdb or whatever device name you have; also make sure both drives are in the BIOS boot order list if possible).

Create swap partition of 1x your RAM if under 16GB, 0.5x your RAM if 16GB or more (should be on a hardware R10, R1 or software R10, R1)

Create a 10GB / partition on xfs (should be on a hardware R10, R1 or software R10, R1)

With the remaining space create the mount point /var/lib/libvirt on xfs (should be on a hardware R10, R1 or software R10, R1).

Where possible (if extra disks are avaiable), create a set of software mirrored XFS volumes for backup purposes and NAS backup purposes. Mount it at /VG_BACKUPS

If you want to use LVM for your guests then create a 2GB XFS /boot paritition on RAID1, a 10GB + however many GB RAM you have (so you have 32GB create a 42-50GB partition) XFS / parition on LVM on RAID1 or 10 and a SWAP partition on LVM on RAID1 or 10. During setup make sure the Volume Group (VG) is as large as possible since we need it empty for snapshot purposes. The reason for the larger / partition due to RAM size is that the virtual guests will save their RAM states here on suspend. And once you're in the Virtual Machine Manager add your Logical Volume Group as a storage pool, name it VG.

Setup network as you see fit, DHCP to start with is fine, this must be working and enabled for NTP to be configured. Ideally use 1 NIC for access/management bridge and 1+ NICS for use as network bridge for virtual guests, or use bonding and VLANs and bridges (configure the bridge NICs later).

Select your timezone, enable NTP

Minimal

Begin install and create your root password.

This is optional, if you do this then add sudo to all subsequent commands when logged in as your sudo user.

useradd example_user && passwd example_user
usermod -aG wheel example_user

dnf install vim

Logout of root and login using sudo user

sudo vim /etc/ssh/sshd_config

then set

PermitRootLogin no

sudo systemctl restart sshd

After install and reboot do a dnf update then add basic Gnome install:

sudo dnf install gnome-classic-session gnome-terminal nautilus-open-terminal control-center liberation-mono-fonts vim tar gnome-disk-utility gnome-system-monitor firefox rsyslog
sudo systemctl enable rsyslog
sudo systemctl start rsyslog

If you want Gnome to load on reboot run the commands below (though you don’t need to if you are only going to use VNC for remote management)

sudo unlink /etc/systemd/system/default.target
sudo ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target

Install Virtualization packages (virt-manager for a nice GUI for your virtual clients)

  
sudo dnf install libvirt virt-manager

https://computingforgeeks.com/use-virt-manager-as-non-root-user/

sudo usermod -aG libvirt example_user

Edit libvirtd.conf

sudo vim /etc/libvirt/libvirtd.conf

Uncomment the following:

unix_sock_group = "libvirt"
unix_sock_rw_perms = "0770"

You may also want to give the libvirt group r/w access to the /var/lib/libvirt/images directory so that you can scp remotely to and from using your sudo user since root ssh is disabled.

sudo chown root:libvirt /var/lib/libvirt/images
sudo chmod 771 /var/lib/libvirt/images
sudo chmod g+s /var/lib/libvirt/images

Restart libvirtd

sudo systemctl restart libvirtd

If you used SSD drives on MDADM (linux software RAID) then enable FSTRIM service for cleanup

sudo systemctl enable fstrim.timer
sudo systemctl start fstrim.timer

Check status of timer by showing systemd timers:

systemctl list-timers

Check trim support by:

lsblk --discard

Stop writing a timestamp every time a file is accessed Edit the /etc/fstab file and replace all the defaults strings by defaults,noatime.

sudo vim /etc/fstab

For example:

/dev/mapper/rhel-root   /         xfs     defaults        1 1

becomes:

/dev/mapper/rhel-root   /         xfs     defaults,noatime        1 1

If using LVM enable Trim function by editing /etc/lvm/lvm.conf and change

issue_discards = 0

to

issue_discards = 1

Other notes for using SSDs: https://www.certdepot.net/rhel7-extend-life-ssd/

Set the proper performance profile via tuned-adm:

sudo tuned-adm profile virtual-host

then check to make sure:

sudo tuned-adm list

This should adjust the swappiness, change to the deadline scheduler and other things.

By default swappiness is set to 10 with the virtual-host profile, if you really want to try to avoid using RAM set it to 10, though make sure you have enough RAM for all of your guests. You might want to set your virtual guests that run linux the same so they avoid swapping if posssible.

sudo vim /etc/sysctl.conf

Add the following:

vm.swappiness = 1

Disable KSM (memory paging feature for oversubscribing memory on similar virtual guests)

sudo systemctl stop ksmtuned
sudo systemctl stop ksm
sudo systemctl disable ksm
sudo systemctl disable ksmtuned

I'm not sure of the cause but this is the fix, research and determine if a better option exists.

sudo vim /etc/modprobe.d/kvm.conf

Add the line:

sudo options kvm ignore_msrs=1

Install a VNC server so you can quickly manage the VMs remotely:

sudo dnf install tigervnc-server
sudo cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:8.service

Edit the VNC config file (replace <USER> with root)

sudo vim /etc/systemd/system/vncserver@:8.service

Example post edit:

ExecStartPre=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'
ExecStart=/usr/bin/vncserver_wrapper example_user %i
ExecStop=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'

Start VNC server to prompt for password, set a password different from your sudo user password, say no to view only password.

vncserver

Connect on port 5908 using your VNC viewer (preferably TigerVNC)

Note: If you connect via TigerVNC viewer it will show that your connection is insecure. This is because the certificates used aren't trusted, however TLS encryption should be active, you can verify this by pressing F8 when using TigerVNC viewer and checking connection info.

Allow VNC server access

sudo firewall-cmd --permanent --zone=public --add-port=5908/tcp
sudo firewall-cmd --reload
sudo systemctl daemon-reload
sudo systemctl enable vncserver@:8.service
sudo systemctl start vncserver@:8.service

*Note: on older Dell servers this isn't supported anymore, definitely not R710/R410/R210 generation* and as of Feb 2020 RHEL8 isn't yet supported by DSU or SRVADMIN

If you are using a Dell server and LSI RAID controller it is recommended that you download and install Dells OMSA and use Dell System Update to update things. Dell: http://linux.dell.com/repo/hardware/dsu/ Set up the Dell OpenManage Repository at like this:

curl -O https://linux.dell.com/repo/hardware/dsu/bootstrap.cgi
sudo bash bootstrap.cgi
sudo dnf install srvadmin-all dell-system-update

run dsu to update firmware/bios/etc

sudo dsu

Note: RHEL 8 has removed libssh2, you need to use epel to get it

sudo dnf install epel-release
sudo dnf install libssh2

Note: you can login to OMSA from the local computer at: https://localhost:1311
Login as root otherwise you won't be able to change things.

Network Bridge for virtual clients. It is recommended to have a dedicated (or multiple dedicated) bridge(s) for your clients(if more than 1 bridge, separate bridges need to be vlan’ed or go to separate networks or you’ll create a loop), lag groups for better throughput is good too. Also, use a separate network card for management and file transfers that won’t interfere with bridged network traffic:

Use a consistent bridge name across hosts to move VMs is easy, remember case sensitive to! Recommend naming them BR0, BR1, BR2, BRX. Please try to have consistency across hosts so if you have two bridges on 1 host, have 2 bridges on all others configured the same way, connected to the same switched network.

To find the HWADDR do this:

ethtool -P <if-name>

or

ip link

if-name is the name of the Ethernet interface, normally eth0 or em0 or eno1.

In the /etc/sysconfig/network-scripts directory it is necessary to create 2 config files. The first (ifcfg-eth0) (or ifcfg-em1 or em0 or eth0 etc) defines your physical network interface, and says that it will be part of a bridge:

 
sudo vim /etc/sysconfig/network-scripts/ifcfg-eno1

Configure as so:

DEVICE=eno1
HWADDR=00:16:76:D6:C9:45 (Use you actual HWADDR, or mac address here)
ONBOOT=yes
BRIDGE=br0

The second config file (ifcfg-br0) defines the bridge device:

 
sudo vim /etc/sysconfig/network-scripts/ifcfg-br0

Configure as so:

DEVICE=br0
TYPE=Bridge
BOOTPROTO=none
ONBOOT=yes
DELAY=2

WARNING: The line TYPE=Bridge is case-sensitive - it must have uppercase 'B' and lower case 'ridge'

Also, if you have only 1 Ethernet adapter you will want to give the Bridge device an IP on your LAN for management, see static IP example below. After changing this restart networking (or simply reboot) .

nmcli connection reload && systemctl restart NetworkManager

Example of ifcfg-br0 for static IP:

DEVICE=br0
TYPE=Bridge
BOOTPROTO=none
ONBOOT=yes
DELAY=2
IPADDR=10.222.190.249
NETWORK=10.222.190.0
NETMASK=255.255.255.0
GATEWAY=10.222.190.250
DNS1=208.67.220.220
DNS2=208.67.222.222

This is used if you are going to copy virtual guests between hosts

Install NFS packages and enable services

sudo dnf install nfs-utils libnfsidmap
sudo systemctl enable rpcbind
sudo systemctl enable nfs-server
sudo systemctl start rpcbind
sudo systemctl start nfs-server
sudo systemctl start rpc-statd
sudo systemctl start nfs-idmapd

make a directory called VG_BACKUPS in /var/lib/libvirt/images

mkdir /var/lib/libvirt/images/VG_BACKUPS

We have to modify “/etc/exports“ file to make an entry of directory “/var/lib/libvirt/images” that you want to share .

sudo vim /etc/exports

Example of exports file

/var/lib/libvirt/images 172.21.21.0/24(rw,sync,no_root_squash,fsid=<somenumber>)

/var/lib/libvirt/images: this is the shared directory
172.21.21.0/24: this is the subnet that we want to allow access to the NFS share
rw: read/write permission to shared folder
sync: all changes to the according filesystem are immediately flushed to disk; the respective write operations are being waited for
no_root_squash: By default, any file request made by user root on the client machine is treated as by user nobody on the server.(Exactly which UID the request is mapped to depends on the UID of user “nobody” on the server, not the client.) If no_root_squash is selected, then root on the client machine will have the same level of access to the files on the system as root on the server.
fsid=somenumber gives the mount a unique id so that mounts are more easily managed by hosts. I recommend using the first and last octets of the host static IP as the “somenumber”

Export the the NFS share

sudo exportfs -r

We need to configure firewall on NFS server to allow client servers to access NFS shares. To do that, run the following commands on the NFS server.

sudo firewall-cmd --permanent --zone public --add-service mountd
sudo firewall-cmd --permanent --zone public --add-service rpc-bind
sudo firewall-cmd --permanent --zone public --add-service nfs
sudo firewall-cmd --reload

sudo dnf install nfs-utils libnfsidmap
sudo systemctl enable rpcbind
sudo systemctl enable nfs-server
sudo systemctl start rpcbind
sudo systemctl start nfs-server
sudo systemctl start rpc-statd
sudo systemctl start nfs-idmapd

Set SELinux options

sudo setsebool -P nfs_export_all_rw 1
sudo setsebool -P virt_use_nfs=on

Create mount points for NFS shares

sudo mkdir /mnt/ VHSRV02/VG_IMAGES

(where VHSRV02 is the remote computer name, make one for each mount you will have). Client FSTAB entry to mount NFS share:

172.18.18.24:/var/lib/libvirt/images     /mnt/VHSRV02/VG_IMAGES         nfs4    noauto,nofail,x-systemd.automount,_netdev,x-systemd.device-timeout=14,proto=tcp,rsize=131072,wsize=131072 0 0
192.168.21.14:/VG_BACKUPS     /mnt/VHSRV02/VG_BACKUPS               nfs4    noauto,nofail,x-systemd.automount,_netdev,x-systemd.device-timeout=14,wsize=131072,rsize=131072 0 0

Virtual Guest Tips:
In Windows Guests, set their page/swap file to as small a size as possible, or try system managed.
On Windows Guests, use Virtio NICs and Virtio SCSI (not just Virtio for HDD). For the HDD set cache mode to none and threads to native.
On all linux guests use virtio NICS Virtio SCSI (not just Virtio for HDD). For the HDD set the cache mode to none and threads to native.
In linux guests (that use systemd), change the swappiness to reduce memory swaps by editing /etc/sysctl.conf and adding the line: vm.swappiness=10 then reboot. Check what your swappiness is by running: cat /proc/sys/vm/swappiness
Limit swap use
Edit the /etc/sysctl.conf file and paste the following lines:
vm.swappiness=1
vm.vfs_cache_pressure=50
Make the changes active:
# sysctl -p
Use a SSD-friendly I/O scheduler
Edit the /etc/default/grub file and add elevator=deadline at the end of the GRUB_CMDLINE_LINUX variable.
Make the change active:
# grub2-mkconfig -o /boot/grub2/grub.cfg

 On all virtual guests, set the CPU to “copy host CPU configuration” and set he topology manually, set leave the sockets and threads at 1 and use cores to allocate virtual CPUs.

If power is lost or server isn't shutdown cleanly then the VNC server service might not restart on boot and manually restarting the VNC service fails. Normally the fix is to delete the lock files in the /tmp folder.

https://access.redhat.com/discussions/1149233 Example:

[root@xxx ~]# ls /tmp/.X
.X0-lock   .X1-lock   .X11-unix/ .X2-lock
[root@xxx ~]# rm -Rf /tmp/.X0-lock
[root@xxx ~]# rm -Rf /tmp/.X1-lock
[root@xxx ~]# rm -Rf /tmp/.X11-unix
[root@xxx ~]# rm -Rf /tmp/.X2-lock

And when connecting be sure you're connecting via port 5908 if you followed the setup according to this document, so… ip.add.r.ess:5908 (otherwise it defaults to 5900).

If your virtual host becomes unplugged from a network switch then all network interfaces (bonds, bridges, vlans and vnets) will go down. On plugging it back in the bonds, bridges and vlans will come back up automatically but the vnets won't. This means your virtual guests won't have network access until your shut them down then back on. Using

ip link setup vnet<x> up 

seems like it brings the interface up and the guest can ping out but devices on the other side of the vnet interface can't seem to get in. Still working on an automated way to fix this. Nice IP command cheatsheet from Redhat: https://access.redhat.com/sites/default/files/attachments/rh_ip_command_cheatsheet_1214_jcs_print.pdf

I am still unclear if the guests cleanly shutdown when the host is issued a shutdown -r now, there is a config file

/etc/sysconfig/libvirt-guests

where options can be set on what to do but I haven't tested them. Here is a link to some info from Redhat: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_deployment_and_administration_guide/sect-shutting_down_rebooting_and_force_shutdown_of_a_guest_virtual_machine-manipulating_the_libvirt_guests_configuration_settings

Also, if you shutdown your virtual guests to do dnf updates on the host, if any of the guests are set to autoboot at startup then will automatically start after an update to libvirt is installed. They will also do this if you restart libvirtd.