 Introduction
to SolarisTM Web Start Flash
John S. Howard
The Solaris 8 Operating Environment (OE) 4/01 release introduced
the Solaris Web Start Flash extensions to the JumpStart framework.
Web Start Flash extends the JumpStart framework by adding the mechanism
to create a Flash archive, a system snapshot of the Solaris OE and
all installed software, from a master machine. This archive can
then be used to rapidly install client systems; this installation
client may be any hardware platform capable of running the Solaris
OE, including those hardware platforms typically referred to as
"servers".
This article will explain how to identify the master machine as
well as provide recommendations and examples of creating and administering
Flash archives. This article assumes the reader has an understanding
of basic Solaris OE or UNIX systems administration skills and a
basic understanding of JumpStart technology and the Solaris OE installation
procedure.
The JumpStart Framework
JumpStart technology is Sun Microsystems' mechanism for controlling,
performing, and automating network-based installations of the Solaris
OE. The JumpStart framework provides a mechanism to help automate
and control installation of the Solaris OE. By automating installation
of the Solaris OE, the chances for human error or configuration
errors during installation may be greatly reduced. This also helps
ensure the consistency of system installation and adherence to site-standards
throughout your data center, as well as providing documentation
as to exactly how the system was installed.
The Flash facility extends the traditional JumpStart installation
framework by adding the mechanism to create a system archive, a
snapshot of an installed system, and install the Solaris OE from
that archive.
A traditional JumpStart software installation is performed by
using the JumpStart profile to specify individual software packages
or software package clusters (a predefined set of software packages)
to be installed. The suninstall program, using the pkgadd
mechanism, then installs the specified packages sequentially. As
the pkgadd mechanism needs to update the installed package
database as well as relocate files, this may become a time-consuming
operation.
The Flash Archive
Flash provides a mechanism by which a specific or reference installation
of the Solaris OE is archived. That Flash archive can then be used
to install the Solaris OE. The reference installation is created
from the on-disk Solaris OE and includes all installed software.
This system on which the archive is created is designated as the
master machine. The reference installation can be a Solaris OE installed
by any means such as a JumpStart software installation, installation
from CD, an interactive installation, etc.
After identifying the master machine, the reference installation
is captured in a Flash archive. This archive (a central feature
of Flash) is essentially a point-in-time snapshot of the Solaris
OE, software patches, and applications on the master machine. The
Flash extensions add the ability to install the archive from an
NFS server or an HTTP server, in addition to installation from a
traditional JumpStart server. The archive also can be accessed from
a disk device (including CD-ROM) or tape device, local to the installation
client. The Flash archive is transmitted over the network to the
installation client and written to the disk. After the archive is
written to the installation client's disk, any necessary archive
modifications are performed. For example, configuration files such
as /etc/nsswitch.conf on the installation client may need
to vary from the master machine. The Flash mechanism enables automation
of modifications, allowing for differences in kernel architecture
or device differences between the master machine and the installation
client to be automatically resolved.
Additionally, Flash allows for partitioning differences between
the master machine and the installation client to be resolved automatically.
For example, if the Flash archive was created on a system with a
single root (/) partition and the installation client has separate
/ and /var partitions, the Flash archive automatically
customizes itself to the installation client. However, the installation
client partitioning must be correctly specified in the JumpStart
profile.
It is important to note that, unless explicitly excluded, the
Flash archive will contain all software installed on the master
machine. For example, if a flash archive is created from a database
server, that archive contains all software that was installed on
that database server -- including the database server software.
This feature makes Flash a powerful tool for deploying complex server
configurations. A complex system architecture only needs to be implemented
and configured once and then a Flash archive created; all subsequent
system installations from that Flash archive will be identical.
For systems such as database servers, the Flash archive should be
created before the system goes into production. For example, a database
server or LDAP server should have its archive created after the
database management software has been installed, but before the
databases have been created and populated.
Software that stores configuration information outside of a UNIX
filesystem may not be correctly configured on the Flash installed
client. For example, logical volume management software such as
Veritas Volume Manager (VxVM) or Solstice DiskSuite software store
meta-information (such as logical volume layout and RAID configuration
information) in raw partitions, outside of a filesystem. Installing
a system from a Flash archive created on a master machine that was
using VxVM with an encapsulated and mirrored boot disk is not possible.
Since the flash archive creation does not (and can not) access the
meta-information in the VxVM private regions, any subsequent installation
from that Flash archive would be incomplete and unbootable.
To incorporate such software in a Flash archive, the archive must
be created on the master machine after all software has been installed,
but before the software has been configured. Again using the example
of a master machine with a VxVM encapsulated and mirrored boot disk,
the Flash archive should be created after the Solaris OE is installed
and VxVM packages have been added and before executing vxinstall
to configure the VxVM software. The VxVM configuration of the installation
client, including encapsulation and mirroring of the boot disk,
can be performed from a finish script after the Flash archive is
installed.
The Flash archive is a snapshot of a system and as such, all specified
files on that system are included in the archive. If a Flash archive
is created from a system in use, some files need to be cleaned up
or zeroed out after the Flash archive is installed. Examples of
these types of files include log files, such as those found in /var/adm,
and any files in the /var/tmp directory. Log files can be
easily zeroed out from a finish script after installation. In the
case of temporary directories, such as the /var/tmp directory,
it is recommend to exclude those directories when the Flash archive
is created.
It is important to note that an initial installation must be specified
when performing a Flash installation. Flash cannot be used to upgrade
a system.
Installation of the Solaris OE via a Flash archive can be dramatically
faster than with other mechanisms, depending on factors such as
network traffic and disk speeds. This is partly because Flash does
not need to individually install each software package and update
the installed package database. Since the Flash archive contains
the installed packages and an accurate package database, the archive
is essentially written to the installation disk as fast as the data
can be taken off the network.
Identifying the Master Machine
Before performing a Flash installation, a master machine must
be identified. The master machine is the system that serves as the
template to be copied onto the installation clients. All software
and files on the master machine, unless specifically excluded, become
a part of the Flash archive and are installed on the client.
Usually, the master machine is not the JumpStart server. However,
the JumpStart server is an ideal system to act as a repository for
Flash archives.
Each system type in your data center should have a corresponding
Flash archive created to install additional systems of that type.
For example, identify a reference configuration for each class of
database server, Web server, backup server, etc., then create Flash
archives of those systems to use when the new systems need to be
deployed.
Store Flash archives offsite, on tape or on CD-ROM, to prepare
for business continuity in the event of a disaster. You can then
use these Flash archives at a remote site or disaster recovery site
to rapidly deploy software-identical, but not necessarily hardware-identical,
replacement systems.
Creating and Administering Archives
The following flarcreate command creates an archive, named
S8-web.archive, of a Solaris 8 OE 4/01 production Web server
(excluding the /var/tmp directory) with an archive creator
string of j.s.howard@Sun.COM:
www06# pwd
/var/tmp/FlashArchives
www06# flarcreate -n "Solaris 8 web server image" \
> -a "j.s.howard@Sun.COM" \
> -R / \
> -x /var/tmp \
> /var/tmp/FlashArchives/S8-web.archive
Determining which filesystems will be included in the archive...
Determining the size of the archive...
The archive will be approximately 446.45MB.
Creating the archive...
Archive creation complete.
The -R option specifies to recursively descend from the specified
directory, and the -x option excludes the specified directory.
See the flarcreate(1M) man page for details on these and other
options.
Flash archives can be accessed via NFS or HTTP. Additionally,
Flash archives can be written to disk, CD, or tape and subsequently
accessed from the disk, CD, or tape drive local to the client, during
installation.
Flash archives can be compressed by specifying the -c option
to the flarcreate command. Compressed archives are automatically
uncompressed after being transferred to the installation client,
prior to installation. See the flarcreate(1M) man page for
additional details.
Use the flar command to extract information from a specified
archive. For example, to determine how an archive was created:
www06# flar -i S8-web.archive
archive_id=04291958b038020b87b749ee62085654
files_archived_method=cpio
creation_date=20010326223306
creation_master=www06
content_name=Solaris 8 workgroup server image
files_compressed_method=none
files_archived_size=468105216
content_author=j.s.howard@Sun.COM
content_architecture=sun4u
The flar command also provides options to split or combine
archives. Consult the flar(1M) man page for additional details
on archive usage.
The JumpStart Profile
The JumpStart profile in the configuration file is used to specify
software configuration information to the installation client as
well as the type of installation to be performed. When using Flash,
only the following profile keywords are valid:
- install_type
- partitioning -- Only the keyword values of explicit
or existing must be used.
- filesys -- The keyword value of auto must not be
used.
- fdisk -- This is valid for Intel Architecture only.
The following example profile specifies that Flash is used as
the installation type, flash_install. Additionally, the profile
instructs that the Flash archive is accessed via NFS, from the location
specified by the archive_location keyword:
install_type flash_install
archive_location nfs://10.1.1.8/jumpstart/FlashArchives/ \
S8-webserver.archive
partitioning explicit
#
# 4GB / and 1GB swap on a 18GB disk
#
filesys rootdisk.s0 450:1786 /
filesys rootdisk.s1 1:449 swap
Since name_service=NONE is specified in the following sysidcfg
file, an IP address is used for the archive_location in the
profile.
The rules entry used for this example is:
model SUNW,UltraSPARC-IIi-cEngine \
- \
Profiles/S8-webserver-Flash.profile \
Finish/EE_Lab-Flash.fin
The sysidcfg file used is:
system_locale=en_US
timezone=US/Pacific
network_interface=primary {netmask=255.255.255.0
protocol_ipv6=no}
terminal=vt100
security_policy=NONE
root_password=QH311oT1ff8TU
name_service=NONE
timeserver=localhost
A root password is specified in the sysidcfg file. This specification
overrides the root password contained in /etc/shadow within
the Flash archive.
After you have created or edited the above files, verify the rules
file. Be certain to use the check script from the Solaris 8 OE 4/01
CD-ROM and verify the rules file:
server01# cd /jumpstart
server01# ./check
Validating rules...
Validating profile Profiles/S8-webserver-Flash.profile...
The custom JumpStart configuration is ok.
The finish script used for this example is:
#!/bin/sh
# EE_Lab-Flash.fin
# Finish script for default EE_Lab setup, Jumpstart Flash
#
# clean up after flash archive install
#
for i in /a/var/adm/messages* /a/var/adm/utmpx \
/a/var/adm/wtmpx /a/var/adm/lastlog
do
cp /dev/null ${i}
done
mkdir /a/var/tmp
chown root:sys /a/var/tmp
chmod 1777 /a/var/tmp
The /var/tmp directory needs to be created by the finish script
because it was excluded when the archive was created with the flarcreate
command.
To perform the installation, the OpenBoot Prom (OBP) command is
executed on the installation client:
{3} ok boot net - install
Summary
This article has introduced the Solaris Web Start Flash facility,
available with Solaris 8 OE 4/01. A Flash overview, the concepts
of a Flash archive, and a master machine were presented. The use
of Flash archives for business continuity was also recommended.
This article also presented the use of the flarcreate command
to create Flash archives and the flar command to administer
Flash archives. Additionally, the changes to the JumpStart profile
necessary to support Flash installations were presented. Those changes
include the ability to use NFS, HTTP, or devices local to the installation
client as locations of the Flash archive during installation. Finally,
an example of creating a Flash archive and finish script for a Web
server was detailed.
Portions of this article may have been excerpted from the author's
book JumpStart Technology: Effective Use in the Solaris Operating
Environment.
2001 Sun Microsystems, Inc. All rights reserved.
Sun, Sun Microsystems, the Sun Logo, Solaris, JumpStart, and Solstice
DiskSuite are trademarks or registered trademarks of Sun Microsystems,
Inc. in the United States and other countries.
UNIX is a registered trademark in the United States and other
countries, exclusively licensed through X/Open Company, Ltd.
John S. Howard is a Senior Staff Engineer with Sun's Enterprise
Engineering group. John joined Sun in 1995 and has 19 years experience
in high-end datacenter implementations, including developing tools
and procedures to minimize mean time to repair (MTTR) and recovery
for Sun Clusters and StarFireTM systems. John may be reached
by email at j.s.howard@Sun.COM.
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