Host

ZStack ZSphere 4.10.6>ZStack ZSphere Documentation>ZStack ZSphere User Guide>Compute Management>Host

A host is a sub-resource of a cluster and can run one or more virtual machines. This section describes how to use hosts in the following chapters:

Host Basic Operations

You can understand the basic operations supported by hosts from the perspective of adding, deleting, modifying, and querying.

Add a Host
Modify a Host
Access a Host
View a Host
Delete a Host

Add a Host

The platform provides multiple entry points to add hosts. You can add one or multiple hosts from the following two main entry points:

In the navigation bar on the left side of the platform page, right-click the target cluster and click Add Host.
In the navigation bar on the left side of the platform page, select the target cluster. Then, on the right side of the platform page, click Actions > Add Host, or in the Hosts sub-page, click Add Host.

ZStack ZSphere supports configuration of the following three major categories of information:

Basic Information: includes name description, associated cluster, and labels

Name: host name
Description: host description
Cluster: cluster where the host resides
Tag: supports binding one or more labels to identify different hosts. For more details, see Tag Management

Host Information: includes addition method, IP address range, and SSH configuration:

Addition Method: add a single host or multiple hosts. When adding multiple hosts, ensure all hosts have the same SSH configuration.
IP Address: enter the IP address or IP address range of the host based on the addition method.
SSH Port: SSH port of the host, default is 22.
SSH Username: username for the host. Default is root.
SSH Password: password for the SSH username.

Other Information Configuration: includes IOMMU enablement status and Intel EPT hardware assistance

Scan Host IOMMU Setting: whether the IOMMU (Input/Output Memory Management Unit) function is enabled, used for passthrough of external devices and virtualization scenarios. By default, it is disabled on x86 architecture and enabled on ARM architecture where the BIOS IOMMU is called SMMU.
Note: Before enabling, make sure the IOMMU option is enabled in the host's BIOS.
Intel EPT Hardware Assist: whether Intel EPT hardware assistance is enabled on Intel CPUs to improve CPU performance. Default is enabled.

After clicking OK, the creation process is complete.

After the first host is added to the cluster, ZStack ZSphere automatically creates a default distributed switch, default distributed port group, and default Kernel adapter based on the related configurations of this host for centralized management of the host's management network. For more information, see Network Resource.

Modify a Host

If you need to modify the name or description of an existing host, on the target host page, click ActionsEdit Name and Description, and modify the corresponding information in the pop-up window.

If you need to modify the IOMMU enablement status and Intel EPT hardware assistance settings of an existing host, on the target host page, click ActionsModify Configuration, and modify the corresponding information in the pop-up window.

Access a Host

You can access the host system through the following three methods:

Webshell Terminal Access: you can directly access the host system by clicking on the small terminal window of the target host, or by clicking Actions > Enter Web Terminal.
SSH Access: you can log in using remote login software by entering the SSH information entered when adding the host. To modify SSH information, click Actions > Update SSH Information.
IPMI Access: if you have managed the host through IPMI, you can access the host using IPMI management software. To modify IPMI information, click Actions > Update IPMI Information.

View a Host

If you need to check the usage and allocation of CPU and memory resources for the host, as well as the usage and allocation of all virtual machines under the host, go to the host's Overview details page. For more information, see Capacity Monitoring.

If you need to check the usage trends of CPU, memory, disk, and NIC resources for the host and its virtual machines over time, go to the host's Monitoring tab. For more information, see Resource Performance Monitoring.

Delete a Host

If you need to delete an existing host, on the target host page, click ActionsDelete, and the host will be deleted. You can also delete hosts in batches on the data center resources Cluster and Host page or the cluster resources Host page.

Note:

If the cluster to which the host belongs has loaded shared storage, this operation will stop all VMs on the host. VMs with high availability enabled will automatically migrate to other hosts within the cluster with sufficient resources and restart.
If the cluster to which the host belongs has loaded local storage, this operation will delete all VMs and disks on the host. Proceed with caution.

Host Hardware Device

After adding the host to the ZStack ZSphere platform, you can enter the host's Hardware Device page to view and manage the host's hardware and devices:

Host NUMA Topology

Host NUMA Topology: A pNUMA topology (physical NUMA topology) is the topology of the host NUMA nodes predefined by the CPU vendor based on the host NUMA architecture.

Definitions

Non-Uniform Memory Access (NUMA): Non-uniform memory access (NUMA) is a computer memory design where the memory access time depends on the memory location relative to the CPU. Under NUMA, a processor can access its own local memory faster than non-local memory and thus improves VM performance.
pNUMA Node: A pNUMA node (physical NUMA node) is a host NUMA node predefined based on the host NUMA architecture. It is used to manage the CPUs and memory of the host. A host can have one or more pNUMA nodes. A pNUMA node primarily consists of one or more physical CPU cores (pCPU) and local memory.
vNUMA Node: A vNUMA node (virtual NUMA node) is generated by passing-through associated pNUMA nodes via CPU pinning. It is used to manage the CPUs and memory of a virtual machine. A vNUMA node primarily consists of one or more virtual CPU cores (vCPU) and local memory.
vNUMA Topology: A vNUMA topology (virtual NUMA topology) is the topology of VM NUMA nodes generated by passing-through associated pNUMA nodes via CPU pinning.
Local Memory: Local memory is the memory that a CPU (pCPU or vCPU) accesses through the Uncore iMC (Integrated Memory Controller) of the same NUMA (pNUMA or vNUMA) node. Compared with accessing non-local memory, accessing local memory has lower latencies.

Functionality Principle

After adding the host, ZStack ZSphere supports viewing the host's pNUMA topology and configuring vNUMA for virtual machines running on the host based on this topology.

ZStack ZSphere Virtual machine vNUMA configuration is achieved through CPU pinning, which strictly associates the virtual machine's vCPU with the host's pCPU, allocating specific pCPUs to the virtual machine. During vNUMA configuration, all vCPUs of the virtual machine are pinned to pCPUs, and each vCPU's pinned pCPUs are located within the same pNUMA node.

After vNUMA configuration, the virtual machine directly passes through the associated host pNUMA node topology, generating one or more vNUMA nodes that form the virtual machine's vNUMA topology. Virtual machine vCPUs prioritize accessing local memory within the same node based on the vNUMA topology.

pNUMA Topology

Go to the target host's Overview, and click View pNUMA Topology in the hardware overview information box. ZStack ZSphere host pNUMA topology information is as follows:

Displays all pNUMA nodes of the host and the virtual machine information associated with each node.
Total memory is the local memory of the pNUMA node that can be directly accessed by the pCPU.
Free memory is the local free memory of the pNUMA node that can be directly accessed by the pCPU.
Both total memory and free memory are based on the actual hardware physical memory capacity of the pNUMA node.

Next Chapter: Image Storage