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Thoughts on how to create virtual compute nodes in the HPCC stack. Specifically, trying to solve the need for tiny, but many, compute nodes for the nano physic applications. Like virtual compute nodes with a single core CPU with 100 MB or less of memory running a lean Scientific Linux operating system. Here is a good introduction: http://www.slideshare.net/gpaterno1/comparing-iaas-vmware-vs-openstack-vs-googles-ganeti-28016375

I'll select Ganeti to start with as it appears the simplest to setup. I've no need for services like fail-over or migration. Just the ability to rapidly many tiny nodes from a template. It also appears that Ganeti clusters can be embedded with Openstack later.

On hold, these Xen tools are very nice, no need for Ganeti up front (virt-manager, virt-clone, virsh).

yum install -y --nogpgcheck xen kernel-xen \
virt-manager libvirt libvirt-python python-virtinst

chkconfig xend on

# disable selinux /etc/selinux/config

# add to xen kernel grub line soe stuff
title CentOS (2.6.18-371.6.1.el5xen)
        root (hd0,0)
        kernel /xen.gz-2.6.18-371.6.1.el5 dom0_mem=2048M,max:2048M dom0_max_vcpus=1 dom0_vcpus_pin allow_unsafe loglvl=all guestloglvl=all
        module /vmlinuz-2.6.18-371.6.1.el5xen ro root=/dev/VolGroup00/LogVol00 rhgb quiet 
        module /initrd-2.6.18-371.6.1.el5xen.img

# hostname fully qualified (in case we go to Ganeti later)

# edit some settings in /etc/xen/xend-config, consul links below

# turn off some services with chkconfig
# cups, iptables, ip6tables, autofs, crond, sysstat, bluetooth
# firstboot, ipmi, iscsi, iscsid

reboot

• http://www.howtoforge.com/paravirtualization-with-xen-on-centos-5.6-x86_64
• http://docs.ganeti.org/ganeti/current/html/install.html#installing-the-hypervisor
• https://github.com/jfut/ganeti-rpm/blob/master/doc/install-rhel.rst

Then launch virt-manager to look at your Dom0.

Build a base clone and install what you need (like the Lava scheduler files). Then shut it down.

Now you build a script to clone and post prep new clones build of it.

#/bin/bash

# automate this

virt-clone --original vmdemo --name bvm7 --file /var/lib/xen/images/bvm7.img
# wait 3 mins
sleep 180

virsh start bvm7
# wait 2 mins
sleep 120

# clobber vmdemo rc.local that sets up a static ip that you know rather than dhcp for automation
cd /root
scp rc.local vmdemo:/etc

ssh vmdemo "cat /etc/sysconfig/network | sed s/vmdemo/bvm7/g > /tmp/network"
ssh vmdemo "scp /tmp/network /etc/sysconfig/"

ssh vmdemo "cat /etc/sysconfig/network-scripts/ifcfg-eth0 | sed s/192.168.150.0/192.168.150.7/g > /tmp/ifcfg-eth0"
ssh vmdemo "scp /tmp/ifcfg-eth0 /etc/sysconfig/network-scripts/"

ssh vmdemo reboot
# wait 2 mins
sleep 120

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