coreos-alpha.ipxe

#!ipxe

# Setup shared static IP for bootstrapping

set net0/ip 10.1.173.14
set net0/netmask 255.255.255.0
set net0/gateway 10.1.173.254
ifopen net0

set channel alpha
set base-url http://10.1.173.10/coreos

kernel ${base-url}/${channel}/vmlinuz coreos.autologin coreos.configdrive=1
initrd ${base-url}/${channel}/initrd
boot

Creating config-drive.md

mkfs.vfat -n config-2 -I /dev/sdc
mkdir -p /media/config-drive
mount /dev/sdc /media/config-drive
mkdir -p /media/config-drive/openstack/latest
cp cloud-config.yml /media/config-drive/openstack/latest/user_data
umount /media/config-drive

NOTE mkfs.vfat is provided by the dosfstools package

Creating in vCenter

From an existing VM, such as one running Ubuntu or CentOS, edit the VM settings and add a new Hard Disk:

I created the size with a number of MBs corresponding to the node index :), 15 MB => *.15, 16 MB => *.16, ...

Run the commands above but alter /dev/sdc to /dev/sdb if that new disk is the second one attached to the VM. In my case it was the third, so /dev/sdc for me.

Remove the new disk from that VM and then go over to the CoreOS VM instance. This time in edit VM settings, add "Existing Hard Disk". Click "Add" and navigate to the Datastore folder for the VM (above) and find the vmdk with the size used above:

rancheros.ipxe

#!ipxe

# Setup shared static IP for bootstrapping

set net0/ip 10.1.173.14
set net0/netmask 255.255.255.0
set net0/gateway 10.1.173.254
ifopen net0

# Boot a persistent RancherOS to RAM

# Location of Kernel/Initrd images
set base-url http://10.1.173.10/rancheros

kernel ${base-url}/vmlinuz \
  rancher.state.autoformat=[/dev/sda] \
  rancher.password=rancher \
  rancher.cloud_init.datasources=[configdrive:/media/config-2]

initrd ${base-url}/initrd
boot