Resource Pool

VM Instance

What is VM Instance?

A VM instance is a virtual machine instance running on a host. A VM instance has its own IP address and can access public networks and run application services. ZStack Cloud supports more than 60 VM instances per host.

Architecture

A VM instance consists of the following core components:

Instance: A virtual machine instance running on a host. An instance includes the basic resources such as CPU, memory, operating system, network configurations, and disks.
Image: An image is a template file used to create a VM instance. Images provide the operating system required by a VM instance.
Primary storage: A primary storage is one or more servers that store volume files of VM instances. These files include root volume snapshots, data volume snapshots, image caches, root volumes, and data volumes.
Snapshot: A snapshot is a point-in-time capture of data status in a volume. Before you perform a business-sensitive operation on a VM instance, you can schedule snapshot creation at specified time points to record the state of the VM data. This allows rollback in case of breakdowns.
Networks:
- Flat network: A flat network is connected to the network where the host is located and has direct access to the Internet. VM instances in a flat network can access public networks by using elastic IP addresses.
- VPC network: A VPC network is a private network where VM instances can be created. A VM instance in a VPC network can access the Internet through a VPC vRouter.
Security group: A security group provides security control services for VM NICs. It filters the ingress or egress TCP, UDP, and ICMP packets of VM NICs based on the specified security rules.

Characteristics

VM instances have the following characteristics:

High availability (HA): You can set an HA mode for a VM instance. When the VM instance is stopped due to daily maintenance or exceptions, the HA policy can trigger the automatic restart of the VM instance to improve the VM availability.
Security:
- The VM console allows you to conveniently monitor and manage VM instances. Note that you must have the corresponding permissions before you can log in to the VM console.
- A VM instance supports IP/MAC/ARP anti-spoofing. Abnormal protocol access sent by the VM instance at the data link layer of a host is isolated to block MAC/ARP spoofing and achieve IP anti-spoofing at the network layer.
- You can create an image for a VM instance. The image contains all of the information about the VM instance. You can quickly copy the corresponding resources through the image.
- You can create a snapshot for a VM instance. Before you perform a business-sensitive operation on the VM instance, you can schedule snapshot creation at specified time points to record the state of the VM data. This allows rollback in case of breakdowns.
- A VM instance supports encrypted storage of plain text passwords to protect sensitive data on the VM instance.
- You can set a delete policy for a VM instance, including Direct, Delay, and Never. When you delete a VM instance in the UI, a dialog box is displayed to remind you of the consequences of the deletion. You must acknowledge the risks before you can delete it. This helps to reduce the risks caused by misoperations.
- A VM instance supports role-based access control and permission management.
- A VM instance supports operation logs and auditing, which can meet the needs of security analysis, intrusion detection, resource change tracking, and compliance auditing.
- The Cloud is able to securely segregate the individual guest VM instance.
Scalability:
- A VM instance allows you to modify its CPU and memory online and expand the attached root volumes and data volumes online. You can modify the VM configurations as needed.
- A VM instance supports auto-scaling. The Cloud can automatically trigger VM auto-scaling or self-healing according to business changes.
- A VM instance supports multiprocessing for virtual processors.
- The Cloud is working on supporting fault tolerance with the capacity to provide zero downtime, zero data loss, and continuous availability for the applications running in VM instances in the event of a host failure and supporting up to at least 4 vCPUs per VM instance in fault tolerance.

Scenarios

VM instances can be used in the following scenarios:

Breaks down the traditional IT information silos.
VM instances integrate the business of an enterprise on the cloud and migrate the information service system from traditional physical servers to VM instances. This helps to improve the resource utilization and reduce repeated investments. VM instances realize the rationalized scheduling of resources through intelligent load balancing services. In addition, the VM HA feature can deal with various exceptions to ensure business continuity of VM instances.
Improves the development and testing efficiencies of enterprises.
For modern IT enterprises, the deployment and approval of a development and testing environment is time-consuming, which severely lengthens the business launch cycle. With VM instances, resources can be allocated online, which helps to establish or recover a development and testing environment in seconds. This accelerates the business launch. In the same resource pool, an enterprise can use the environment encapsulated in a VM instance for development at day time and for automated testing at night. After an application development is completed, resources occupied by the corresponding VM instance can be quickly released and assigned to other projects. You can plan resource configurations in advance, allowing projects to apply for needed resources which are assigned to them in time.
Deploys PaaS and SaaS services for enterprises.
For enterprises that cannot migrate PaaS or SaaS services to the public cloud, they can use ZStack Cloud to build a private cloud environment and deploy the PaaS or SaaS services on VM instances. The flexibility, stability, and high concurrency characteristics of the VM instances help to ensure the security, stability, and high-efficiency of the enterprises.
Provides a safe rehearsal environment.
In recent years, network attack defense is tilted towards attackers. Enterprises are facing severe cloud security challenges as various high-risk vulnerabilities, APT targeted attacks, and computer viruses emerged in an endless stream. By using VM instances, enterprises can build a completely isolated security rehearsal environment and ensure the business security through monitoring and alarming, log auditing, vulnerability management, anti-virus and other means.
3D rendering, artificial intelligence (AI), and cloud desktop.
VM instances with GPU passthrough have strong computing capabilities and can be used in thin terminal scenarios such as 3D rendering, AI, and cloud desktops.
- 3D Rendering
  3D rendering is commonly used in the movie production and three-dimensional video games. In these scenarios, a GPU server cluster is often used to satisfy the high compute requirements. The VM GPU passthrough feature provided by ZStack Cloud enables both a low performance loss (within 5%) and a centralized and efficient cluster management. Coupled with intelligent monitoring and billing, it provides a complete set of convenient and efficient rendering farm solution.
- Artificial Intelligence
  Enterprises can build a TensorFlow-based AI application by using VM instances with GPU passthrough. The powerful computing capabilities of GPU devices can fully meet the infrastructure requirements of large-scale model trainings.
- Cloud Desktop
  GPU devices play a critical role in the field of cloud desktop applications, not only optimizing the desktop visual experience, but also providing main computing capabilities in special applications. Replacing traditional PC graphics stations, GPU devices allow users to implement their 3D work in a safer environment. By using VM instances with GPU passthrough and protocols such as RDP and PCoIP, users can fully enjoy the capabilities of graphics cards and obtain a near-physical machine experience.

View VM Instances

ZStack Cloud provides two method to display VM instance: List View and Directory View. A directory view can display VM instances by cluster or by group. You can specify how VM instances are displayed as needed to achieve a higher resource management efficiency.

Switch VM Instance View

By default, VM instances are displayed in a list view. You can flexibly switch the VM instance view as needed.

You can click the switch button in the upper right corner of the VM Instance page to switch the VM display view on the current page.

You can set VM Instance View in Global Setting. VM instances are displayed according to the global setting on all relevant pages.

Method: On the main menu of ZStack Cloud, choose Settings > Global Setting > Advanced > Resource Center > Resource Pool > VM Instance. Then, set VM Instance View as needed.

Figure 3. Set VM Instance View in Global Setting

List View | Introduction

Displays VM instance information in a list, such as the VM name, state, CPU, memory, and supported actions.

Directory View | Introduction

Displays VM instance in a directory tree form. You can click the switch button above the directory tree to make it display VM instances by clusters where VM instances locate or by groups that VM instances are affiliated to.
Note:
- Currently, ECS instances in Hybrid Cloud Management cannot be displayed in directory views.
- Directory views are displayed to admin and platform managers. and sub-accounts cannot see a directory view.
  Figure 4. Switch Display Method in Directory View
When you create associated resources based on VM instances, you can filter needed VM instances by cluster or by group, such as alarms, backup jobs, CDP tasks, and scheduled jobs.
Figure 5. Filter VM Instances When Creating Associated Resources

Directory View | Display By Cluster

Provides a cluster directory tree to display VM instances, helping you view the VM affiliations to clusters and hosts conveniently.
The cluster directory tree displays all clusters in the current zone and hosts in each cluster. You can specify a cluster to view VM instances in this cluster, or specify a host to view VM instances running on the host.
You can search a host in the directory tree quickly by the host name.
You can collapse or expand a whole cluster directory tree.

Directory View | Display By Group

Provides a group directory tree to display VM instances, helping you view groups that VM instances belong to conveniently.
The group directory tree displays all VM groups in the current zone and hierarchical relationships between the groups. You can specify a group to view VM instances in this group and its sub-groups.
You can search a group quickly in the directory tree quickly by the group name.
You can collapse or expand a whole group directory tree.

Note:

Groups are separated according to zones where they locate. The directory tree in the current zone does not include groups in other zones.
A directory tree on the VM Instance page does not include vCenter VM groups.

Directory View | Group Types

ZStack Cloud supports two types of VM groups: system groups and custom groups.

System Group: System groups are automatically provided by the system, including All and Default. All is the root directory in a group directory tree. Default is affiliated to All and is used to manage VM instances that are not allocated to any custom groups.
Custom Group: Custom groups are created manually as you need. All custom groups are affiliated to the root directory All.

Directory View | Manage Group

ZStack Cloud allows you to create and manage VM groups. The following lists the actions you can perform on a group.

Action	Description
Create Group	Create one-level or multiple-level groups. Note: To create a group, you need to set a group name that is 1 to 20 characters in length and contains only Chinese characters, English letters, digits, spaces, or the following characters: ()（）【】@._-+. The name of the group you create cannot be used by an existing group on the same hierarchy. You can create at most four levels of groups (including the root directory group). You cannot create sub-groups for Default.
Create VM Instance	Create VM instances in a specified group. Note: Only custom groups support this action. You cannot perform this action on All and Default.
Rename	Modify the name of a group. Note: You can modify names only for custom groups. You cannot perform this action on All and Default.
Delete Group	Delete a Group. Note: All and Default cannot be deleted. Deleting a group also deletes all its sub-groups. Deleting a group does not delete VM instances in it. After the group is deleted, VM instances in this group and its sub-groups are moved to Default.

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