describes the major components of Ignite and where they come from. Ignite installation and recovery is described in terms of phases, with each phase described in detail.

The Ignite-UX install environment

HP-UX installation and recovery is accomplished using the Ignite-UX install environment.

The Ignite install environment is a small subset of the HP-UX operating system that allows HP-UX to install itself onto a system. During the initial phases of installation and recovery, the install environment runs in client memory without any disk-based storage. A memory-based RAM disk holds the initial root file system needed for HP-UX operation. While operating with a memory-based root disk file system, file system space is very limited. On smaller memory systems, memory for the HP-UX kernel and processes might also be limited. Command libraries and other files must be loaded and removed as needed. (Increasing the size of the memory-based root disk to make more space would result in insufficient memory being available for the processes that accomplish installation and recovery.) Once the correct disks are identified, volumes and file systems are created. The install environment then switches to a disk-based file system. When that is completed, some of the RAM disk space is freed.

The Ignite install environment consists of:

•[WVI]INSTALL – The HP-UX install kernel, which is statically linked and includes a wide variety of I/O and other modules so it is able to run on all supported systems.

•[WVI]INSTALLFS – The initial HP-UX install file system, which is copied into the root RAM disk during boot. The first 8 KB can contain Ignite-UX configuration content.

•INSTCMDS or INSTCMDSIA, SYSCMDS or SYSCMDSIA, and RECCMDS or RECCMDSIA –

Archives of commands, libraries, and other files needed to accomplish installation and recovery, but are not needed to initially get the install environment running. These are loaded as needed during installation and recovery.

The Ignite-UX install kernel and install file system are loaded into system memory by the standard HP-UX boot loader or virtual system boot loader software. Note that there are a number of boot sources where the Ignite install environment may reside. Also, the details of booting vary according to your Ignite data center configuration.

Boot sources

Ignite always retrieves the install kernel and install file system from the boot source. By default, Ignite retrieves INSTCMDS[IA], SYSCMDS[IA], and RECCMDS[IA] from that same boot source, but can get these command archives from a different source if requested to. Ignite can determine the boot source by querying the HP-UX kernel.

Ignite can switch its source for command archives and depots if configuration information in the install file system instructs it to, or if instructed to by the Ignite user interface.

Ignite will operate in the same manner, regardless of the boot source.

Installation versus recovery

Ignite internally uses the same approach, regardless of whether you are performing an installation or recovery. The terms “installation” and “recovery” are valuable to describe intended use, but Ignite's internal operation make it possible to blur the distinction between the two, such as when you use golden images.

This design is quite powerful, and allows Ignite to handle significant system differences during recovery by adapting as needed and regressing to more install-like behavior if required.

Network booting and IP addresses

When a system boots HP-UX from an Ignite-UX server, it needs an IP address to get the operating system kernel. This first IP address is not necessarily the same IP address the system will be assigned

How Ignite works 19