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You might want to know little bit more about Aptus before installation. This is a brief introduction of Aptus components.
Aptus provides the Intelligent Union Architecture on Linux (IUA), which is an implementation of global name space shared-root file system. Aptus uses the Union File System (Unionfs) at the server to separate non shareable files with the clients. It is used to secure server files and separate all the non-shareable information between server and clients, leaving all the remaining files shared. This design also minimize duplication of configuration files, allowing centralization of configuration modifications at the server.
Rootfs template is a distribution specific package. Rootfs template define rule sets in IUA which tells Unionfs the rules for non-shareable files, such as server system configurations and network configurations. It provides a rule set for UnionFS to control the file system behavior. Other than data separation, it also provides a different System V init mechanism for clients. So that it handles Aptus clients bootup which differs from the server.
Aptus provides remote boot service. The "Aptus server daemon (aptusd)" handling Aptus client remote boot requests and DHCP requests. It is used for network address management for Aptus clients. For "aptusd" version greater or equal to 2.0.6 have built-in support for PXE clients. You can now boot Linux using Aptus with standard PXE boot roms.
Aptus clients use a special Linux kernel to boot, the kernel image is stored at the server's file system and is then loaded through NFS or tftp at boot time.
Etherboot, which is a set of client remote boot firmware. You will need Etherboot if your client doesn't have a built-in PXE boot rom . It supports most of the Linux supported Ethernet adapters. Individual Ethernet adapters requires a different boot firmware that has its network device drivers built-in, each of those exists in the form of boot floppy disk image, DOS executable binary or binary boot ROM image. At startup, the boot firmware sends requests to Aptus server and load the kernel image over the network. The client executes the downloaded kernel and mount its file system over the network.
Aptus provides a GUI management tool called "Aptus Configurator" which is a Webmin module. You will also need Webmin to run "Aptus Configurator". "Aptus Configurator" automates all the complex configurations by not require users to edit configuration files and manage services manually.
The aim of Aptus is to replicate the same Linux OS on the client using a distributed file systems approach and provides a synchronized global name space and security management across multiple Linux machines. So that applications and configurations at the server will be shared by clients automatically, this will make system administration centralized. After installation, a directory /var/opt/aptus will be created, this directory is refered as the Aptus Server Root which contains all the important files used by Aptus clients and the Union Filesystem mount points.
Aptus also requires configure various services at the server. Such as the time server which is used to synchronize times with clients and server, remote logging of client log messages, NIS (Network Information Service) for centralized user account management(optional, system administrators can choose to use LDAP and other services), and NFS (Network File System) server to export file systems and share with Aptus clients over ethernet.
For more details and technical details, please see the section Appendix A.
