Nova provides key services for managing the SUSE Cloud, sets up the Compute Nodes. SUSE Cloud currently supports KVM, Xen and Microsoft Hyper V and VMWare vSphere. The unsupported QEMU option is included to enable test setups with virtualized nodes. The following attributes can be configured for Nova:
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Scheduler Options: Virtual RAM to Physical RAM allocation ratio
Set the “overcommit ratio” for RAM for instances on the Compute Nodes. A ratio of 1.0 means no overcommitment. Changing this value is not recommended. Scheduler Options: Virtual CPU to Physical CPU allocation ratio
Set the “overcommit ratio” for CPUs for instances on the Compute Nodes. A ratio of 1.0 means no overcommitment.
Live Migration Support: Enable Libvirt Migration
Allows to move KVM and Xen instances to a different Compute Node running the same hypervisor (cross hypervisor migrations are not supported). Useful when a Compute Node needs to be shut down or rebooted for maintenance or when the load of the Compute Node is very high. Instances can be moved while running (Live Migration).
WARNING: Libvirt Migration and Security
Enabling the libvirt migration option will open a TCP port on the Compute Nodes that allows to access to all instances from all machines in the ad- min network. Ensure that only authorized machines have access to the admin network when enabling this option.
Live Migration Support: Setup Shared Storage
Sets up a directory /var/lib/nova/instances on the Control Node on
which nova-multi-controller and exports it via NFS to all compute nodes. This set- up is required for live migration of Xen instances (but not for KVM) and can be used to provide central handling of instance data. Enabling this option is only rec- ommended if Xen live migration is required—otherwise it should be disabled.
KVM Options: Enable Kernel Samepage Merging
Kernel SamePage Merging (KSM) is a Linux Kernel feature which merges identi- cal memory pages from multiple running processes into one memory region. En- abling it optimizes memory usage on the Compute Nodes when using the KVM hypervisor at the cost of slightly increasing CPU usage.
VMware vCenter Settings
Setting up VMware support is described in a separate section. See Appendix F,
SSL Support: Protocol
Choose whether to encrypt public communication (HTTPS) or not (HTTP). If choosing HTTPS,refer to “SSL Support: Protocol ” (page 105) for configuration details.
SSL Support for noVNC: Protocol
After having started an instance you can display its VNC console in the OpenStack Dashboard (Horizon) via the browser using the noVNC implementation. By default this connection is not encrypted and can potentially be eavesdropped.
Enable encrypted communication for noVNC by choosing HTTPS. Refer to “SSL Support: Protocol ” (page 105) for configuration details.
Verbose
Shows debugging output in the log files when set to true.
Figure 5.17: The Nova Barclamp
The Nova service consists of six different roles:
nova-multi-controller
Distributing and scheduling the instances is managed by the Nova-multi-controller. It also provides networking and messaging services. Nova-multi-controller needs to be installed on a Control Node.
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nova-multi-compute-hyperv / nova-multi-compute-kvm / nova-multi-compute-qemu / no- va-multi-compute-vmware / nova-multi-compute-xen
Provides the hypervisors (Hyper-V, KVM, QEMU, VMware vSphere and Xen) and tools needed to manage the instances. Only one hypervisor can be deployed on a single compute node but you can use different hypervisors in your cloud by deploying different hypervisors to different Compute Nodes. A Nova-mul- ti-compute role needs to be installed on every Compute Node. However, not
all hypervisors need to be deployed.
Each image that will be made available in SUSE Cloud to start an instance is bound to a hypervisor. Each hypervisor can be deployed on multiple Compute Nodes (except for the VMWare vSphere role, see below). In a multi-hypervisor deployment you should make sure to deploy the nova-multi-compute roles
in a way, that enough compute power is available for each hypervisor.
NOTE: Re-assigning Hypervisors
Existing nova-multi-compute nodes can be changed in a produc-
tive SUSE Cloud without service interruption. You need to “evacuate” the node, re-assign a new nova-multi-compute role via the Nova bar-
clamp and Apply the change. nova-multi-compute-vmware can only be deployed on a single node.
IMPORTANT: Deploying Hyper-V
nova-multi-compute-hyperv can only be deployed to Compute
Nodes running either Microsoft Hyper-V Server or Windows Server 2012. Being able to set up such Compute Nodes requires to set up a netboot environment for Windows. Refer to Appendix E, Setting up a Netboot En- vironment for Microsoft* Windows (page 187) for details.
The default password for Hyper-V Compute Nodes will be “crowbar”.
IMPORTANT: Deploying VMware vSphere (vmware)
VMware vSphere is not supported “natively” by SUSE Cloud—it rather delegates requests to an existing vCenter. It requires preparations at the vCenter and post install adjustments of the Compute Node. See Appen- dix F, VMware vSphere Installation Instructions (page 191) for instruc- tions. nova-multi-compute-vmware can only be deployed on a single Com- pute Node.
Figure 5.18: The Nova Barclamp: Node Deployment Example with Three KVM Nodes
5.11.1 HA Setup for Nova
Making Nova highly available requires no special configuration—it is sufficient to de- ploy it on a cluster.
As of SUSE Cloud 4 making Compute Nodes highly available is not supported. See Section 2.7.3, “High Availability of the Compute Node(s)” (page 33) for additional in- formation.