Install LDoms Manager & Configure the Primary Domain

Before you can create guest domains, the primary domain must be configured as a control/service domain and LDoms Manager (ldmd) needs to be running. In many Oracle SPARC systems this is mostly preconfigured, but you should still know all the checks and also how to save the layout into an SP configuration (spconfig).

Role of the primary / control domain

Control plane

Runs ldmd and controls creation, binding and starting/stopping of all domains.

Default service & I/O

Often also provides virtual disk and network services to guests.

Admin entry point

You log into the primary domain to run ldm and manage the entire SPARC server.

Typical journey

Verify platform supports LDOMs.
Install/verify LDoms Manager.
Enable ldmd service.
Confirm primary has correct roles (control/service/io).
Save final layout to SP config (spconfig).

Step-by-step: configure primary/control domain

1. Check platform is LDOM-capable

virtinfo and prtconf can show virtualization support on SPARC.

terminal — primary domain

ldoms-lab

[root@primary ~]# virtinfo -a
Platform:  sun4v
Logical Domains support: enabled
Role: control primary io service
 
[root@primary ~]# prtconf -vp | grep -i sun4v

2. Check & install LDoms Manager package

Depending on Solaris/firmware, LDoms Manager is pkg or preinstalled.

terminal — primary domain

ldoms-lab

[root@primary ~]# pkg list '*ldoms*'
NAME (PUBLISHER)                         VERSION                 IFO
system/ldoms/ldomsmanager                3.6-0.175.3.0.0.30.0    i--
 
# If not installed:
[root@primary ~]# pkg install system/ldoms/ldomsmanager

3. Enable ldmd service (LDOM manager daemon)

ldmd manages all domain configuration and runs in control domain.

terminal — primary domain

ldoms-lab

[root@primary ~]# svcs ldmd
STATE          STIME    FMRI
disabled       10:12:34 svc:/platform/sun4v/ldmd:default
 
[root@primary ~]# svcadm enable ldmd
 
[root@primary ~]# svcs ldmd
STATE          STIME    FMRI
online         10:13:01 svc:/platform/sun4v/ldmd:default

4. Basic ldm list output on fresh system

Shows the primary/control domain and current resources/roles.

terminal — primary domain

ldoms-lab

[root@primary ~]# ldm list
NAME             STATE      FLAGS   CONS    VCPU  MEMORY   UTIL  UPTIME
primary          active     -n-cv   SP      8     32G      5%    2d 3h
 
# FLAGS typically show roles:
#  c = control domain
#  v = virtual I/O service domain
#  n = master domain
#  i/o roles depend on config

5. List and create SP configurations (spconfig)

Save current domain layout into SP (service processor) config so it can survive OS reinstall.

terminal — primary domain

ldoms-lab

# List existing SP configs
[root@primary ~]# ldm list-spconfig
factory-default
initial-setup
 
# Save current running configuration as a new SP config
[root@primary ~]# ldm add-spconfig prod-layout
 
# Verify again
[root@primary ~]# ldm list-spconfig
factory-default
initial-setup
prod-layout

SP configuration (spconfig) – what it is and why it matters

When you create domains with ldm, the configuration is stored in the control domain (primary) and in the SP (service processor) when you explicitly save it as an SP configuration, usually called spconfig.

What is an SP config file?

A named snapshot of the current LDOM layout stored on the SP (not just inside Solaris).
Contains domain definitions, CPU/memory assignments, vdisk/vnet mappings etc.
Examples: factory-default, initial-setup, prod-layout.

Use cases of SP config

If you reinstall or repair the primary domain OS, you can rebuild LDOM layout from SP config.
Move from temporary lab layout to final production layout and save it as a named config.
Keep multiple named configs for different scenarios (e.g. normal vs. maintenance layouts).

What if you never create SP config?

Domain layout lives only in the running control domain OS.
If that OS/disk is lost or reinstalled without export, you lose the LDOM configuration.
Disks/LUNs might still exist, but you must manually recreate all domains and mappings.
So in real environments, you should ALWAYS save a stable layout using ldm add-spconfig.

Important notes

Primary domain is critical: if it is down, you usually cannot manage other domains.

After building or modifying domains, take a new SP config (ldm add-spconfig) and note the name in your documentation.

Combine SP configs with regular ldm list-bindings exports and ZFS snapshots of domain disks for complete DR strategy.