Help Center/ Huawei Cloud Flexus_Huawei Cloud Flexus X Instance/ Service Overview/ Notes and Constraints
Updated on 2024-11-14 GMT+08:00
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Notes and Constraints

To ensure that your FlexusX instances run properly, read the following notes and constraints before using them.

Quotas

There are quota limits for the number of FlexusX instances, the number of vCPUs, and the RAM memory capacity. FlexusX instances share the quotas with ECSs. You can view the ECS quotas on the Quotas page to obtain the available quotas of FlexusX instances, as shown in Figure 1. If the quotas do not meet your requirements, apply for a higher quota.

Figure 1 FlexusX instance quotas

Regions

  • Once FlexusX instances are purchased, the region or AZ cannot be changed.
  • Resource prices may vary in different regions. For details, see Product Pricing Details.
  • For regional resources (such as images, EVS disks, cloud backups, security groups, and EIPs), FlexusX instances can only use resources in the same region.

Images

  • Images are regional resources. FlexusX instances can only use private images that are in the same region as them.
  • Only private images created using x86 servers are supported in FlexusX.
  • Only Linux images are supported.
  • When you use a private image to create a FlexusX instance or change the OS, ensure that the instance specifications (vCPUs, memory, and system disk capacity) meet the requirements of that private image. Otherwise, the private image cannot be used.

EVS Disks

  • When you purchase a FlexusX instance, the EVS disk device type is VBD by default and cannot be changed. After purchasing a FlexusX instance, you can add SCSI data disks.
  • When you purchase a FlexusX instance, you can add a maximum of 24 disks (1 system disk and 23 data disks). After purchasing a FlexusX instance, you can add a maximum of 60 disks.

    If more data disks are required, attach them after purchasing a FlexusX instance. To query the number of disks that can be attached to FlexusX instances of different specifications, see Querying Information About Disks Attached to an ECS.

  • After a new data disk is attached to a FlexusX instance, you need to initialize the data disk before using it.

For details about EVS constraints, see the EVS Notes and Constraints.

VPCs

When using a VPC, you need to plan VPCs, subnet CIDR blocks, security groups, virtual IP addresses, and elastic NICs. For details about VPC constraints, see Notes and Constraints.

EIPs

  • If a FlexusX instance needs to access the Internet, bind an EIP to the instance.
  • EIPs are regional resources. It cannot be used across regions or accounts. Each EIP can be used by only one FlexusX instance at a time, and they must be in the same region.

For more EIP constraints, see Notes and Constraints.

Other Constraints

  • FlexusX instances do not support nested virtualization.
  • Do not install external hardware devices, such as encryption dongles or USB flash drives on FlexusX instances.

Notes

When using FlexusX instances, comply with the notes below.

  • Do not use FlexusX instances as unauthorized servers for any illegal or violation service, such as gambling or cross-border VPN.
  • Do not use FlexusX instances for fraudulent transactions, such as click farming on e-commerce websites.
  • Do not use FlexusX instances to initiate network attacks, such as DDoS attacks, CC attacks, web attacks, brute force cracking, or spreading of viruses and Trojan horses.
  • Do not use FlexusX instances for traffic transit.
  • Do not use FlexusX instances for web crawling.
  • Do not use FlexusX instances to detect other systems like scanning or penetration unless otherwise being authorized.
  • Do not deploy any illegal websites or applications on FlexusX instances.
  • Do not use FlexusX to send spams or engage in activities that violate personal privacy.
  • Do not stop system processes if you are not sure about the consequences. Otherwise, blue screen of death (BSOD) or a restart may occur on FlexusX instances.
  • Ensure that there is at least 2 GiB of idle memory. Otherwise, BSOD, freezing, or service failures may occur.
  • Do not modify the registry. Otherwise, the system startup may fail. If the modification is mandatory, back up the registry before modifying it.
  • Do not modify the clock settings. Otherwise, DHCP lease may fail, leading to the loss of IP addresses.
  • Do not delete the CloudResetPwdAgent or CloudResetPwdUpdateAgent process. Otherwise, one-click password reset will become unavailable.
  • Do not disable virtual memory. Otherwise, system performance may deteriorate, or system exceptions may occur.
  • Do not delete the VMTools program, or an exception may occur on FlexusX instances.
  • Do not modify the /etc/issue file. Otherwise, the OS distribution will not be identified.
  • Do not delete system directories or files. Otherwise, the system may fail to run or start.
  • Do not change the permissions for or names of system directories. Otherwise, the system may fail to run or start.
  • Do not upgrade the kernel of the Linux unless necessary.

    When you have to upgrade the Linux kernel, follow the instructions provided in How Can I Upgrade the Kernel of a Linux ECS?

  • Do not delete the CloudResetPwdAgent or CloudResetPwdUpdateAgent process. Otherwise, one-click password reset will become unavailable.
  • Do not change the default /etc/resolv.conf of the DNS server. Otherwise, software sources and NTP may be unavailable.
  • Do not modify default intranet configurations, such as the IP address, subnet mask, or gateway address of a FlexusX instance. Otherwise, network exceptions may occur.
  • Manually specified IP addresses for Linux FlexusX instances are generally static IP addresses. To avoid network exceptions caused by conflicts between NetworkManager and internal network services, do not enable NetworkManager when not required, such as when installing Kubernetes.