Vnx-rootfsfedora

How to create a KVM Fedora root filesystem for VNX

Follow this procedure to create a KVM Fedora based root filesystem for VNX. The procedure has been tested with Fedora 24, 20, 18, 16 and 14.

Basic installation

• Create the filesystem disk image:

qemu-img create -f qcow2 vnx_rootfs_kvm_fedora.qcow2 20G

• Get Fedora installation DVD (use the complete DVD; do not use the Live version, as it seems the installation wizard does not include the customization menu). For example:

wget ftp://ftp.rediris.es/mirror/fedora/16/Fedora/i386/iso/Fedora-16-i386-DVD.iso
cp Fedora-16-i386-DVD.iso /almacen/iso

• Create the virtual machine with:

vnx --create-rootfs vnx_rootfs_kvm_fedora.qcow2 --install-media /almacen/iso/Fedora-16-i386-DVD.iso --mem 768M

Note: add "--arch x86_64" option for 64 bits virtual machines

• Follow the Fedora installation assistant. At some point, you will have to choose among different system profiles: desktop, web server, minimal, etc.
• Enable login on the first serial line:
• Fedora 18, 20 and 24:
• Edit /etc/default/grub and add:

GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8  net.ifnames=0 biosdevname=0"
GRUB_TERMINAL="serial"
GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1"

• And afterwards execute:

grub2-mkconfig -o /boot/grub2/grub.cfg

• Fedora 16. Execute this command:

ln -s /usr/lib/systemd/system/getty@.service   /etc/systemd/system/getty.target.wants/getty@ttyS0.service

• Fedora 14. Create a file named /etc/init/serial-ttyS0.conf with the following content:

#This service maintains a getty on /dev/ttyS0.
start on stopped rc RUNLEVEL=[2345]
stop on starting runlevel [016]
respawn
exec /sbin/agetty /dev/ttyS0 9600 vt100-nav

And add ttyS0 to /etc/securetty file if you want to login root on that console:

echo "ttyS0" >> /etc/securetty

• Finally, delete the net udev rules file and halt the system:

rm /etc/udev/rules.d/70-persistent-net.rules
halt -p

Configuration

• Restart the system with the following command:

vnx --modify-rootfs vnx_rootfs_kvm_fedora.qcow2 --update-aced --mem 768M

Note: ignore the errors "timeout waiting for response on VM socket". 768M are needed if you are installing a root filesystem with desktop interface Note: add "--arch x86_64" option for 64 bits virtual machines

• Access the system through the text console to easy the copy-paste of commands:

virsh console vnx_rootfs_kvm_fedora.qcow2

• Check that you have network connectivity. Maybe you have to activate the network interface by hand:

dhclient eth0

Note: use "ip link show" to know which network interface to use.

• Update the system and install additional packages

yum update
yum install perl perl-XML-LibXML perl-NetAddr-IP acpid udisks perl-Sys-Syslog xterm

Note: if yum fails, check that the network is working. Maybe you will have to manually execute "dhclient eth0", at least in the case of a minimal installation.

• Install VNX autoconfiguration daemon:

mount /dev/sdb /mnt/
perl /mnt/vnxaced-lf/install_vnxaced

• Disable Network Manager to avoid problems with autoconfiguration daemon

systemctl stop NetworkManager.service 
systemctl disable NetworkManager.service
systemctl enable network.service 

• If you have chosen a "minimum installation", activate network services (they are disabled by default):

chkconfig --level 3 network on

• Optionally:
• Install other services needed, for example, an apache server:

yum install httpd
chkconfig httpd off  # if you want to avoid automatic start of apache server

• Or, if using a "minumum installation", install network utilities:

yum install telnet wget openssh-clients

• If you want automatic login, just edit /etc/gdm/custom.conf and add the following lines:

AutomaticLoginEnable=true
AutomaticLogin=vnx

• Disable the firewall. Firewall is enabled by default; that could be problematic for testing purpose systems. If desired, disable it graphically in "System|Administration|Firewall" option, or using the following command from the command line:

# Fedora 18
chkconfig firewalld off

# Fedora 16 & 14
chkconfig iptables off
chkconfig ip6tables off

• Change grub timeout to 0 by editing /etc/default/grub file and setting:

GRUB_TIMEOUT=0

and executing:

grub2-mkconfig -o /boot/grub2/grub.cfg  

• Disable screensaver if using a GUI.
• Create a file /etc/vnx_rootfs_version to store version number and informacion about modification. For example:

VER=v0.25
OS=Fedora 18
DESC=Basic Fedora 18 root-filesystem without GUI

• Finally, stop the virtual machine with:

vnx_halt

vnx_halt deletes some caches and log files and optionally lets you write a short message to /etc/vnx_rootfs_version file describing the latest modifications done.

Installing additional software

To install additional software or to modify your root file system, you just have to:

• Start a virtual machine from it:

vnx --modify-rootfs vnx_rootfs_kvm_fedora.qcow2

• Check network connectivity. Maybe you have to activate the network interface by hand:

dhclient eth1

Note: use "ip link show" to know which network interface to use.

• Do the modifications you want.
• Finally, halt the system using:

vnx_halt

Updating VNXACED

You can automatically update the VNXACE daemon with the following command:

vnx --modify-rootfs vnx_rootfs_kvm_fedora.qcow2 --update-aced -y

If VNXACE daemon is not updated automatically, you can do it manually by accessing the virtual machine console and type:

mount /dev/sdb /mnt/
perl /mnt/vnxaced-lf/install_vnxaced