HP Integrity Virtual Machines Installation, Configuration, and Administration Version A.03.50

10.3 Network and Storage Migration Considerations
Effective migration of VM Host systems depends on proper configuration of the networks and
storage used by the source and destination hosts. The hpvmmigrate command verifies that the
source and destination hosts provide the guest with symmetric accessibility to network and
storage resources. If you set up the configuration properly on both hosts before you migrate the
guest, the migration task will be much easier and faster.
10.3.1 Network Configuration Considerations
The source and destination hosts should be on the same subnet. The hpvmmigrate command
preserves the MAC address of the guest being migrated. Thus, having the hosts on the same
subnet prevents problems that can occur from changing the guest’s host name or IP address.
With both hosts on the same subnet, the guest boots properly on the destination host.
In addition, ensure that all pNICs are symmetrically configured on both the source and destination
hosts. For example, if lan0 on HostA is connected to subnet A, and lan1 is connected to subnet
B, make sure that, on HostB, lan0 is connected to subnet A and lan1 is connected to subnet B.
10.3.2 Storage Configuration Considerations
Both the source and destination hosts must share access to symmetrically configured storage
devices. Specifically, both hosts must use the same character disk-device file name for each disk
device. For example, both the source and destination hosts would refer to the same disk device
as /dev/rdsk/c0t1d0. (To configure the source and destination systems with the same device
file names, use the ioinit command to reassign instance numbers to the ext_bus class.)
Also, the same storage devices must be visible to both the source and destination hosts. The
hpvmmigrate command uses the Fibre Channel worldwide identifier (WWID) to determine
whether the storage allocated to a guest on the source host is also reachable on the destination
host.
The hpvmmigrate command assumes that guests use storage area network (SAN) resources
specified as whole-disk backing stores (for example, /dev/rdsk/c26d5t2). Although you can
create virtual machines with direct attached storage (DAS), guests that use DAS cannot be
migrated.
To avoid inadvertently using the disk devices associated with a guest on more than one host,
mark as restricted all the disk devices used for guest storage on all hosts, except the disk that
contains the guest. To mark a disk as restricted, use the hpvmdevmgmt command. For example:
# hpvmdevmgmt –a rdev:entry_name
The –a option accepts the name of the device to be restricted. For example:
# hpvmdevmgmt –a rdev:/dev/rdsk/c4t1d0
For more information about the hpvmdevmgmt command, see Chapter 7 (page 81).
10.3.3 Security Considerations
The hpvmmigrate command requires HP-UX Secure Shell (SSH) to be set up on both the source
and destination host systems. SSH provides a secure communication path between hosts and is
installed on HP-UX 11.23 systems by default. To enable secure communication between the
source and destination hosts, you must generate SSH keys on both systems.
The hpvmmigrate command uses SSH public-key based authentication between the source and
destination hosts. Password and hostbased authentication are not supported.
You need root privileges to generate and set up the SSH keys required for guest migration.
146 Migrating Virtual Machines