CloudStack CentOS Template – Install From ISO

This is a part 1/3 creating CentOS 6.x CloudStack template with the following features:

Minimal and fully updated CentOS 6.5 for 32-bit and 64-bit platforms with guest OS tools
Root password management using cloudstack-guest-set-passwordscript
SSH key management using cloud-init

Register CentOS ISO

Login to CloudStack management UI
Navigate to ‘Templates’ and select view ‘ISO’ from the drop-down list
Click ‘Register ISO’. Use the latest CentOS release ISO, which at this time (as of Jan 2014) is CentOS 6.5
Set ‘Name’ and ‘Description’ fields to CentOS-6.5-x86_64-minimal.iso
Set the URL to the nearest ISO mirror. I usedhttp://mirror.leapswitch.com/centos/6.5/isos/x86_64/CentOS-6.5-x86_64-minimal.iso for CentOS 6.4 64-bit andhttp://mirror.leapswitch.com/centos/6.5/isos/i386/CentOS-6.5-i386-minimal.iso for the 32-bit version.
Check the ‘Bootable’ checkbox
Set the OS Type field to ‘CentOS 6.4 (64-bit)’ as CentOS 6.5 is not listed in the drop down list as of CloudStack 4.2.0. Use OS Type ‘CentOS 6.4 (32-bit)’ for the 32-bit ISO
Click OK button to start the download
CloudStack will now start to download the ISO from the mirror. You can check the status by clicking on the ISO’s name
Wait for the ISO download and complete registration successfully. It takes a few minutes depending on the speed of your connection

Once the ISO registration is completed, create a new instance with the ISO

Create CentOS Instance

Click on ‘Instances’ and ‘Add Instance’. Select ‘ISO’ button and click‘Next’
From the ‘Select A Template’ screen, select ‘CentOS-6.5-x86_64-minimal.iso’ ISO from the ‘My ISOs’ section. Also choose the hypervisor type and click ‘Next’.
Select a ‘Compute Offering’ and click ‘Next’. A 1vCPU/512MB offering is what I have used
Choose a ‘Data Disk’ offering. I have used a 20GB disk
Choose defaults for ‘Affinity’ and ‘Network Offering’
Set the instance ‘Name’ from the ‘Review’ screen and ‘Launch VM’. I typically use the format os+version-hypervisor+arch. So CentOS 6.5 64-bit on XenServer becomes ‘centos65-xen64’ for easy identificationIn my environment, I end up with 4 golden instances per OS. So for CentOS 6.5, it’s centos65-xen32, centos65-xen64, centos65-kvm32 andcentos65-kvm64 instances
Wait for the instance to start ‘running’. Takes a few seconds depending on the performance of your CloudStack IaaS infrastructure
Click on the running instance ‘centos65-xen64’ for additional details

Once the instance is running, connect via the console and complete the installation

Install CentOS

Connect via the console. You would have the Anaconda install screen waiting for you to start the installation. Skip the disk check.
CentOS Language Selection. I chose ‘English’
CentOS keyboard selection. I chose ‘US’ default
CentOS detects the 20GB Virt-IO based data disk. Re-Initialize all disks
Select the ‘Time Zone’. I choose ‘UTC/GMT’ as default as my hypervisors run on UTC timezone. The end user can always change his timezone as appropriate later
Pick a root password. It does not matter what you use here as we will build the template to automatically as a ‘password enabled’ template. Lets use ‘password’ for now.
Use the entire 20GB disk vda
Write changes to the disk. The installer would now partition and format the disk.
Wait for the package installation to complete. Might take a few minutes depending on your infrastructure Since we are using the minimal CentOS install ISO, you wont be prompted for manual package selection
Reboot once the install completes
Detach the ISO from the instance. You might want to do it very quickly before the OS completes the reboot
Reboot the instance with a console ctrl-alt-del if it happens to be stuck in the installer screen (since we detached the ISO)
centos65-xen64 would now boot and present you with the login prompt
Finally, login as ‘root’

In a minimal CentOS install via the text installer, eth0 is disabled by default. So the first thing to do would be to console login and enable the network interface for eth0 device. Once network is enabled, all other customization tasks would be done over SSH instead of the console.

Enable CentOS Networking

Login as root via console
Update file /etc/sysconfig/network-scripts/ifcfg-eth0 as below and reboot the instance. I use the vi editor for editing files.

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DEVICE=eth0

Type=Ethernet

ONBOOT=yes

NM_CONTROLLED=no

BOOTPROTO=dhcp
Reboot the instance

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[root@localhost ~]# reboot
After reboot, the hostname of the instance would have changed fromlocalhost to centos65-xen64 indicating that the networking service is running with DHCP settings.
sshd would also be running. Also identify the IP address assigned to eth0. It would match the NIC settings found on the instance’s NIC details page. In this case, eth0 is 10.1.1.38 and matches the CloudStack assigned NIC 1 IP address.
Assign a static SNAT IP to centos65-xen64 to make it reachable from an external network. Also open SSH port from the firewall settings. In this case, the SNAT IP is 192.168.64.106.
Check ICMP Pings and SSH access as root user