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Chapter 11.
85
Working With Virtual Machines
11.1. About Working with Virtual Machines
CloudPlatform provides administrators with complete control over the life cycle of all guest VMs
executing in the cloud. CloudPlatform provides several guest management operations for end users
and administrators. VMs may be stopped, started, rebooted, and destroyed.
Guest VMs have a name and group. VM names and groups are opaque to CloudPlatform and are
available for end users to organize their VMs. Each VM can have three names for use in different
contexts. Only two of these names can be controlled by the user:
• Instance name – a unique, immutable ID that is generated by CloudPlatform, and can not be
modified by the user. This name conforms to the requirements in IETF RFC 1123.
• Display name – the name displayed in the CloudPlatform web UI. Can be set by the user. Defaults
to instance name.
• Name – host name that the DHCP server assigns to the VM. Can be set by the user. Defaults to
instance name.
Note
You can append the display name of a guest VM to its internal name. For more information, see
Section 11.6, “Appending a Display Name to the Guest VM’s Internal Name”.
Guest VMs can be configured to be Highly Available (HA). An HA-enabled VM is monitored by the
system. If the system detects that the VM is down, it will attempt to restart the VM, possibly on a
different host. For more information, see Section 18.2, “HA-Enabled Virtual Machines”.
In a zone that uses basic networking with EIP enabled, each new VM is by default allocated one public
IP address. When the VM is started, CloudPlatform automatically creates a static NAT between this
public IP address and the private IP address of the VM.
If Elastic IP is in use (with the NetScaler load balancer), the IP address initially allocated to the new
VM is not marked as elastic. The user must replace the automatically configured IP with a specifically
acquired elastic IP, and set up the static NAT mapping between this new IP and the guest VM’s
private IP. The VM’s original IP address is then released and returned to the pool of available public
IPs. Optionally, you can also decide not to allocate a public IP to a VM in an EIP-enabled Basic zone.
For more information on Elastic IP, see Section 16.18, “About Elastic IP”.
CloudPlatform cannot distinguish a guest VM that was shut down by the user (such as with the
“shutdown” command in Linux) from a VM that shut down unexpectedly. If an HA-enabled VM is shut
down from inside the VM, CloudPlatform will restart it. To shut down an HA-enabled VM, you must go
through the CloudPlatform UI or API.
11.2. Best Practices for Virtual Machines
For VMs to work as expected and provide excellent service, follow these guidelines.