1. Quattor Advanced Tutorial, LAL
AII v2
Michel Jouvin
LAL, Orsay
Quattor Advanced Tutorial, LAL
December 18, 2008

2. Outline Why AII v2 ? How to use it AII Configuration New features
Disk partitioning
Hooks
AII v1 to v2 migration
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AII v2

3. Why AII v2 ? AII v1 had severe limitations AII v2 design principles
Based on pan-template templating system, very difficult to maintain
Kickstart configuration template
File system configuration was very complex and new device type like SW or HW raid were difficult to describe
Not modular enough with PXE, DHCP… configuration mixed together
AII v2 design principles
Direct access to XML profile in the same way as a component (using the same API)
Distinction between file systems and block devices
A block device can be a JBOD, a HW/SW raid, LVM…
A file system uses a block device
Based on ncm-lib-blockdevices, also used by ncm-filesystem
aii-shellfe is a front-end for various plugins, according to configuration (aii-pxelinux, aii-kernel…)
Extensible through hooks
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AII v2

4. How to Use It ? AII is only one command: aii-shellfe
--configure node: add DHCP and TFTP configuration for PXE, produce a Kickstart configuration file from node profile
--install node: at next PXE boot, start the OS installer
--boot node: at next PXE boot, boot from local disk
--remove node: remove node from DHCP/TFTP config
--rescue node: at next PXE boot, boot a rescue image
Require installation of a rescue image
A node is typically configured (in the BIOS) to always boot PXE
aii-shellfe allows to control what happens at next boot
At the end of initial installation, automatically switch from --install to --boot
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AII v2

5. AII Configuration AII configuration in 2 files under /etc/aii
aii-shellfe.conf: location where to write Kickstart configuration files and URL where to get XML profiles
aii-dhcp.conf: location of DHCP configuration file maintained by Quattor, command to restart DHCPD
Config file may be a dedicated file included in main DHCPD config
Command to restart DHCPD may synchronize config with a remote node and restart DHCPD on a remote machine
Add support for an OS version for PXE
Copy a few files from the OS distribution in the same directory as pxelinux.cfg
Ensure tftpd is started with the appropriate root directory definition (option –s)
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AII v2

6. Disk Partionning
New schema based on a distinct configuration of block devices and file systems
Block devices: any combination of HW/SW raid, JBOD, LVM…
File systems: how block devices are used
New schema is very flexible but also more complex…
A generic template to configure file systems and associated block devices: standard/filesystem/config
Operations to do a almost always the same…
Describe a default layout with all possible block devices and file systems
Use variables to enable/disable them, define their size…
Default layout is a site-specific template whose name is passed in FILESYSTEM_LAYOUT_CONFIG_SITE
See examples for a basis
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AII v2

7. Hooks
Allow to add every required action at different point in installation
E.g. install machine certificate during machine insall
Several hook point: pre, post…
A hook is a Perl script that uses the component API
See man aii-hooks
Hook declaration example:
type begrids_hook = {
"module" : string
"more_stuf": more_field_types };
bind "/system/aii/hooks/post_reboot/0" = begrids_hook;
"/system/aii/hooks/post_reboot" = list (
nlist ("module", "begrid", ...) );
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AII v2

8. AII v1 to v2 Migration v1 and v2 configuration are not compatible
Kickstart template is not use anymore
On the server…
Can be removed (/usr/lib/aii/osinstall)
Templates: AII schema has changed with a real schema defined instead of a schema permitting any key/value pair
Should be transparent when using AII variables introduced at the end of AII v1
No reason to use direct configuration path anymore
Disk partitioning and file systems use a new schema and must be completely rewritten
Use new generic template to configure partitioning with variables if possible
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AII v2

9. Useful Links Quattor QWG wiki
Presentation at Bologna’s Quattor Workshop
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AII v2