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 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.

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.

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.

Create a VM Instance (Fast Creation)

On the main menu of ZStack Cloud, choose Resource Center > Resource Pool > Virtual Resource > VM Instance. You can create a VM instance quickly through one of the following fast creation entrances:

Click the Fast Creation button on the right of Create VM Instance. Then, the Fast Creation page is displayed.
Click Create VM Instance. On the displayed page, click Fast Creation.

On the Fast Creation page, set the following parameters:

Name: Enter a name for the VM instance.
The name must be 1 to 128 characters in length and can contain Chinese characters, letters, digits, spaces, hyphens (-), underscores (_), periods (.), parenthesis (), colons (:), and plus signs (+) and cannot begin or end with spaces.
Quantity: Enter the number of VM instances to be created. Valid values: 1 to 100. You can change the maximum number by modifying the value of Maximum VM Creation in Batch on UI in the global setting.
Note: When you create VM instances in bulk, the names of these VM instances will be followed by -1, -2, -3 and so forth to distinguish these VM instances.
Tag: Optional. Bind one or more tags to the VM instance as needed.
Group: Optional. Choose a VM group for the VM instance. If you do not set this parameter, the VM instance goes to the default group.
Set the VM offering by using one of the following methods:
Basic Offering: You can set the VM offering by selecting an existing instance offering and disk offering. If you select this method, set the following parameters:
- Instance Offering: Select an existing instance offering. The instance offering defines the number of CPU cores, memory size, host allocation strategy, and other configurations of the VM instance.
- Image: Select an existing image. The image is used to install an operating system for the VM instance.
  Note: If you select an Windows-based ISO image that has enabled Virtio, the Virtio drive will be attached to the VM operating system by default. You need to manually install the drive when you install the operating system. If you reboot the VM instance on the UI, the drive will be detached.
- Root Disk Offering: Select an existing disk offering for the root volume of the VM instance. The root disk offering defines the root volume information such as the size and disk bandwidth.
  - If you select a raw or qcow2 image, this parameter is optional. If you do not select a disk offering, the root disk offering will be consistent with the size of the selected image.
  - If you select an ISO image, this parameter is required.
- Data Volume: Optional. Choose whether to create data volumes and attach the volumes to the VM instance. You can attach a default maximum of 24 data volumes to a VM instance. The maximum number can be changed by modifying the global setting Maximum Data Volume. By default, no data volumes is created and attached to the VM instance.
  If you choose to attach a data volume, click Attach Data Volume and set the following parameters:
  - Data Disk Offering: Select an existing disk offering for the data volume of the VM instance. The data disk offering defines the data volume information such as the volume size and disk bandwidth.
  - Quantity: Enter the number of data volumes created from the selected data disk offering that you want to attach to the VM instance.
  - Enable VirtIOSCSI: Optional. Choose whether to use a VirtIOSCSI bus to create a SCSI data volume.
    Note:
    
    By default, VirtioSCSI is enabled if a shared storage is used, indicating that you can create VirtIO SCSI volumes.
    
    If a LocalStorage primary storage is used, you can enable VirtioSCSI on the volume details page.
    
    VirtIOSCSI volumes support multiple I/O queues, which can be identified with IDs (WWN).
Custom Offering: Set the VM offering by customizing the following VM configurations:
- CPU: Set the number of CPU cores of the VM instance. Valid values: 1 to 1024, integer.
- Memory: Set the memory size of the VM instance. Valid values: 16 MB to 1000 TB, integer. Unit: MB, GB, and TB.
- Host Allocation Strategy: The strategy used to allocate a host to the VM instance. This strategy is consistent with the global setting Host Allocation Strategy. You can modify this global setting to specify a host allocation policy for the VM instance.
- Image: Select an existing image. This image is used to install an operating system for the VM instance.
  Note: If you select an Windows-based ISO image that has enabled Virtio, the Virtio drive is attached to the image by default. You need to manually install the drive when you install the operating system. If you restart the VM instance on the UI, the drive will be detached.
- Root Volume: Set the size of the root volume. Valid values: 1 MB to 1024 TB, integer. Unit: MB, GB, and TB.
  - If you select a raw or qcow2 image, this parameter is optional. If you do not select a disk offering, the size of the root disk offering is consistent with the size of the selected image. If you customize a size, make sure that the size is no smaller than the selected image size.
  - If you select an ISO image, this parameter is required. Make sure that the size is no smaller than the selected image size.
- Data Volume: Optional. Choose whether to create data volumes and attach the volumes to the VM instance. You can attach a default maximum of 24 data volumes to a VM instance. The maximum number can be changed by modifying the global setting Maximum Data Volume. By default, no data volumes is created and attached to the VM instance.
  If you choose to attach a data volume, click Attach Data Volume and set the following parameters:
  - Data Disk Offering: Select an existing disk offering for the data volume of the VM instance. The data disk offering defines the data volume information such as the volume size and disk bandwidth.
  - Quantity: Enter the number of data volumes created from the selected data disk offering that you want to attach to the VM instance.
  - Enable VirtIOSCSI: Optional. Choose whether to use a VirtIOSCSI bus to create a SCSI data volume.
    Note:
    
    By default, VirtioSCSI is enabled if a shared storage is used, indicating that you can create VirtIO SCSI volumes.
    
    If a LocalStorage primary storage is used, you can enable VirtioSCSI on the volume details page.
    
    VirtIOSCSI volumes support multiple I/O queues, which can be identified with IDs (WWN).
Network Configurations: Configure the network resources and network services for the VM instance. You can add multiple networks as needed.
- Network: Select an L3 network for the VM instance. Supported network types: VPC network, public network, and flat network.
- Make Default: Set one of the networks as the default network of the VM instance.
- Enable SR-IOV: Optional. Choose whether to use SR-IOV to generate a VF NIC and pass it through to the VM instance. By default, SR-IOV is disabled. You can enable it if you have hardware resources that satisfy related requirements.
  Note: To enable SR-IOV, note that:
  - Make sure that SR-IOV network acceleration mode is used for the L2 network from which the L3 network is created. Otherwise, SR-IOV cannot be enabled.
  - Enabling SR-IOV generates an NIC of the VF type and passes it through to the VM instance.
  - After SR-IOV is enabled, make sure that the physical NIC corresponded by the L3 network has an available VF NIC. Otherwise, the VM instance might fail to be created.
  - If you do not enable SR-IOV:
    - If the L2 network from which the VM L3 network is created uses Normal or Smart NIC network acceleration mode, the VM instance is assigned an NIC of the vNIC type.
    - If the physical NIC in the L2 network from which the L3 network is created is a Smart NIC, and the L2 network uses Smart NIC network acceleration mode, the VM instance is assigned an NIC of the vDPA type.
- Assign IP: Optional. Choose whether to assign an IP address to the VM NIC. By default, this option is not selected and the Cloud automatically assigns an IP address to the VM instance.
  Note: If you choose to assign an IP address, note that:
  - The IP address must be unique within the network segment of the selected network.
  - By default, the drop-down menu displays 5 recommended IP addresses. If the current network has less than 5 IP addresses, all available IP addresses will be displayed.
  - If you create VM instances in bulk and specify an IP address here, the Cloud will automatically assign a range of IP addresses to these VM instances with the IP address you specify as the start IP. If an IP address is occupied or if IP addresses are insufficient within the continuously assigned IP range, the corresponding VM instance will fail to be created.
  - If DHCP is not enabled for the L3 network, we recommend that you assign an IP address to the VM instance.
- MAC Address: Optional. Choose whether to customize a MAC address for the VM instance. By default, this option is not selected and the Cloud automatically assigns a MAC address to the VM instance.
- Security Group: Optional. Associate an existing security group with the VM instance.
- EIP: Optional. Associate an existing elastic IP address (EIP) with the VM instance.
HA Mode: Optional. Choose a high availability (HA) mode for the VM instance when the VM instance is shut down due to planned maintenance or exceptions. Valid values: None and Neverstop.
- If you set the value to None, VM instances does not auto-reboot in case of an abnormal shutdown.
- If you set the value to Neverstop:
  - If hosts are running properly, VM instances with HA enabled can reboot automatically in case of an abnormal shutdown.
  - If hosts are abnormal or enter maintenance mode, VM instances using a LocalStorage primary storage and with HA enabled can reboot automatically in case of an abnormal shutdown.
  - If hosts are abnormal or enter maintenance mode, VM instances using a shared storage and with HA enabled can reboot automatically in case of an abnormal shutdown.
Note:
- You can enable or disable the VM HA feature in the Cloud by using the global setting Enable VM HA Globally, and turn on or off the switch as needed. Default: true.
- If you disable the switch in the global setting, you cannot set HA mode for a VM instance on the VM details page. In this case, the VM business may not be protected by HA. Please exercise with caution.
- You can set the HA mode globally by using the global setting VM HA Mode. Default: none. If you set the mode specifically for a VM instance, this global setting does not take effect on the VM instance.
User Data: Optional. Inject user-defined parameters or scripts to customize configurations for the VM instance or to accomplish specific tasks.
Note: To use user data, note that:
- Before you import the user data, make sure that both the user data network service and DHCP network service work as expected.
- Before you inject user data to Linux-based VM instances, make sure that cloud-init is installed on the images of the VM instances. We recommend that you install cloud-init 0.7.9, 17.1, 19.4, 19.4, or later.
- Before you inject user data to Windows-based VM instances, make sure that Cloudbase-Init is installed on the images of the VM instances. You can install Cloudbase-Init of any version.
- If you set a root user password in user data for a VM instance, the password is displayed in the User Data option on the details page of the VM instance. Make sure that your password is well protected.

Figure 1. Create VM Instance (Fast Creation)