= Initial Installation =
[[TracNav]]

[[TOC(inline)]]

This is a quick introduction to AII configuration. AII is Quattor component in charge of producing Kickstart configuration file used for initial installation.

Configuration specific to initial installation is made of 2 parts :
 * AII_xxx variables used to configure base environment (keyboard, language...). This works both for v1 and v2.
 * Filesystems and block devices definitions : this is specific to AII v2.
 
== AII Variables ==

All AII options may be customized through variables. For the complete list, look at the man pages ''aii-pxelinux(8)'' and ''aii-ks(8)''  or the source code [source:templates/trunk/standard/aii/quattor/ks/config.tpl standard/aii/quattor/ks/config.tpl] and [source:templates/trunk/standard/aii/quattor/pxe/config.tpl standard/aii/quattor/pxe/config.tpl].

A typical AII configuration is :
{{{
# AII specific parameters
variable AII_OSINSTALL_SRV ?= "quattorsrv.lal.in2p3.fr";
# variable AII_ACKSRV ?= "quattorsrv.lal.in2p3.fr";
variable AII_OSINSTALL_ROOT = '/packages/os';
}}}

== Site-Specific Installation Actions ==

AII allows to define in a flexible way site-specific actions that must be done at various points in Kickstart. This is done through several `hooks`.

== File Systems and Block Devices ==

In AII v2, block devices and file systems are declared separatly. Sections belows give some details about how to configure each of them. Block devices entries are used only if referenced by a file system or another block device entry.

=== Generic Configuration of Filesystems ===

QWG Templates provide a generic template to configure file systems on a typical system with 1 or 2 disks. It is based on template [source:templates/trunk/sites/example/site/filesystems/layout.tpl sites/example/site/filesystems/layout.tpl] that may be customized according to your site needs with a limited set of variables. In addition to this generic template to define disk layouts, QWG templates provides 2 examples of how to use it :

 * [source:templates/trunk/sites/example/site/filesystems/glite.tpl sites/example/site/filesystems/glite.tpl] : define a default system disk layout for a typical grid system running gLite. This template also provides some variables to further refine this default layout without redefining everything.
 * [source:templates/trunk/sites/example/site/filesystems/ce_nfs_server.tpl sites/example/site/filesystems/ce_nfs_server.tpl] : add to the basic layout provided by the previous template 2 filesystems, one for home directories and one for VO software areas. It is intended to be used on a machine configured as a NFS server to serve these file systems to WNs (and possibly the CE if it is not the NFS server).
 
These two templates are just provided as examples on how to use [source:templates/trunk/sites/example/site/filesystems/layout.tpl sites/example/site/filesystems/layout.tpl]. But this template can be used to build many other layouts. The basic idea is to declare in this template all the possible file system that can be found on a system, most of them with zero size meaning they will not be created unless the variable used to define their size is explicitly set to a non-zero value.

To use these templates, you need to define the following 2 variables in your node profile or one of your site-specific templates (typically `pro_site_cluster_info`) :
 * `FILESYSTEM_CONFIG_SITE` : define this variable to be source:templates/trunk/sites/example/site/filesystems/layout.tpl sites/example/site/filesystems/layout.tpl]. This is the default in gLite templates.
 * `FILESYSTEM_LAYOUT_CONFIG_SITE` : define this variable to the name of a template that customize source:templates/trunk/sites/example/site/filesystems/layout.tpl sites/example/site/filesystems/layout.tpl] by defining the appropriate variables. gLite templates define it to be [source:templates/trunk/sites/example/site/filesystems/glite.tpl sites/example/site/filesystems/glite.tpl] by default.

=== File Systems ===

Filesystems are declared as an ordered list allowing to customize different aspect of a file system (mount point, mount options, format, ...). Each file system in the list is described as a nlist. One property in the nlist describing a file system is `block device` : its value is an entry in the structure describing block devices (physical disk, logical volumes, ...). To add or modify a filesystem on a system, it is recommended to use 'fileystem_mod` function. An example is :

{{{
"/system/filesystems" = filesystem_mod(
  list(nlist ("block_device", "partitions/" + DISK_PART_BOOT,
              "mountpoint", "/boot",
              "format", true,
              "mount", true,
              "preserve", false,
              "type","ext2"),
       nlist ("block_device", "partitions/" + DISK_PART_SWAP,
              "format", true,
              "mount", true,
              "preserve", false,
              "type","swap",
              "mountpoint","swap"),
       nlist ("block_device", "partitions/" + DISK_PART_ROOT,
              "format", true,
              "preserve", false,
              "mount", true,
              "type","ext3",
              "mountpoint","/"),
       nlist ("block_device", "logical_volumes/usrvol",
              "format", true,
              "preserve", false,
              "mount", true,
              "type","ext3",
              "mountpoint","/usr"),
);
}}}

Look at [source:templates/trunk/sites/example/site/filesystems/layout.tpl sites/example/site/filesystems/layout.tpl] for more details.

=== Block Devices ===

Block devices define logical and physical devices used by file systems. They can be logical devices, HW or SW raid devices, physical disks... A block device can be made of other block devices, for example a logical device is made of one or more physical devices.

Unlike file systems which are described with an ordered list, block devices are defined as a nlist. At installation time, they are processed (partition creation, logical volume creation...) in the order of file systems who use them.

Several functions are available to help in declaration of block devices, in particular :
 * `partition_add(PHYS_DISK,partition_nlist)` : allow to add entries efficiently in `/system/blockdevices/partitions` nlist. 
 * `lvm_add(VOL_GROUP,logvol_nlist)` : allow to add entries efficiently in `/system/blockdevices/logical_volumes` nlist. 

An example of block device definition is :
{{{
"/system/blockdevices/physical_devs" = npush (
  DISK_BOOT_DEV, nlist ("label", "msdos")
);

"/system/blockdevices/partitions" = partitions_add (DISK_BOOT_DEV, nlist (DISK_PART_BOOT, 64*MB,
                                                                          DISK_PART_SWAP, 4*GB,
                                                                          DISK_PART_ROOT, 1*GB,
                                                                          DISK_PART_LOGPARTS, -1
                                                                         )
                                                   );
    
"/system/blockdevices/volume_groups" = npush (
    "vg0", nlist ("device_list", list ("partitions/" + DISK_PART_LOGPARTS))
);

"/system/blockdevices/logical_volumes" = lvs_add ("vg0", nlist("usrvol", 5*GB,
                                                               "homevol", 512*MB,
                                                               "tmpvol", 1*GB,
                                                               "varvol", -1,
                                                              )
);

}}}

Look at [source:templates/trunk/sites/example/site/filesystems/layout.tpl sites/example/site/filesystems/layout.tpl] for more details.


== AII v1 to v2 Migration ==

When migrating from AII v1 to v2, the AII configuration itself should not require many changes, as long as you are using AII-related variables, except for the declaration of Kickstart actions which replace former Kickstart template. The ''aii-update(8)'' man page provides complete information on what is needed now.

== Important note ==

The model for file systems and block devices allows to use partition labels others than '''msdos'''. It is even possible not to use partition tables at all on non-system disks. However, Anaconda doesn't like this and will stop your installations if it finds disks with non-msdos labels. For this reason, AII will only create filesystems that are fully enclosed in msdos-labeled disks. This means the partition beneath a file system, all members of a given software RAID or whatever combination you can think of. Filesystems on other partition tables must be created after the node is installed, for instance with ncm-filesystems.

If you install and miss any file systems on your Kickstart file, please check the labels on all your disks.

On the other hand, file system definition is not backward compatible and must be edited as described before. The full description of the data structures and helper functions is available at [https://twiki.cern.ch/twiki/bin/view/FIOgroup/TsiCDBBlockDevices CERN wiki] You can also find some useful hints and additions at https://twiki.cern.ch/twiki/bin/view/ELFms/QuattorUpdateFSLayout.

== Troubleshooting ==

=== Error creating Fetch object for ... ===

Should you get this message when running `aii-shellfe`, it indicates that `/etc/ccm.conf` is missing. This may happen if your Quattor server is not managed with Quattor. To fix the problem, create one with the following contents:

{{{
debug 0
force 0
cache_root /var/lib/ccm
get_timeout 30
lock_retries 3
lock_wait 30
retrieve_retries 3
retrieve_wait 30
world_readable 1
}}}