Dynamic Root Disk: Quick Start & Best Practices

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When drd runcmd finds the file systems in the clone already mounted, they will not be
unmounted—nor on an LVM-based system will the volume group be vgexported—at the completion of
the drd runcmd operation.
Modifying the Clone
The drd runcmd operation is used to run commands that modify the inactive system image. There
are two fundamental requirements for a command run by the drd runcmd operation:
• The command must not affect the currently booted system. In particular, it must not start or stop
daemons, make dynamic kernel changes, or in any way affect the process space of the booted
system.
• The changes the command makes to the inactive system image must be fully functional when the
image is booted. For example, if a patch installs a new daemon, it is usually necessary that the
daemon be started automatically when the image is booted.
A command, such as swinstall, that satisfies the two fundamental requirements above is
designated as DRD-safe. Similarly, a package whose control scripts behave correctly when executed
under drd runcmd is designated as DRD-safe.
For release 3.3 and later of DRD, the commands certified to be DRD-safe are swinstall(1M),
swlist(1M), swjob(1M), swmodify(1M), swremove(1M), swverify(1M), kctune(1M),
update-ux(1M), and view(1). In addition, there are restrictions on the options that can be used
on the sw* and update-ux commands. These restrictions are documented in the manpage drd-
runcmd(1M).
For more information on DRD safety, please see the BP1: Additional Considerations section later in
this white paper.
Activating & Booting the Clone
When the clone is ready for deployment, the drd activate command can be used to set the
inactive system image as the primary boot path for the next system boot:
# /opt/drd/bin/drd activate
If desired, the alternate boot path and the High Availability (HA) alternate boot path may also be
changed by using the options -x alternate_bootdisk and -x HA_alternate_bootdisk on
the drd activate command. The value of the autoboot flag, set by the command
setboot -b, is not affected by the drd activate command.
The drd activate command always changes the primary boot path to the inactive system image.
(This is the clone until the clone is booted—then the original system becomes inactive.) The drd
activate command does not toggle the boot path between the booted system and the inactive
image. This makes the result of the drd activate command predictable, even if it is issued
multiple times by multiple system administrators.
The option -x reboot can be set to true on the drd activate command if an immediate
shutdown and reboot is desired:
# /opt/drd/bin/drd activate -x reboot=true