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.

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 instances on the L3 network. It filters the ingress or egress TCP, UDP, and ICMP packets of specified VM instances in specified networks based on the specified security rules.
Figure 1. VM Architecture


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 deleting the VM instance. 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.
  • 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.

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 restricts 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 develop its environment by using the encapsulated environment of a VM instance and arrange the testing plan more reasonably. 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 configuration in advance and apply for immediate distribution as needed.

  • 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 with 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 movie production or three-dimensional video games. Due to the extremely high computational intensity, GPU server clusters are often used to provide computing abilities. ZStack Cloud provides GPU passthrough features, which enables extremely low performance loss (within 5%) as well as centralized and efficient cluster management. Coupled with intelligent monitoring and billing, VM instances can form 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 for large-scale model training.

    • Cloud desktop

      GPU devices play a critical role in the field of cloud desktop applications. GPU devices not only upgrade the desktop visual experience, but also assume the main computing role 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.