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  5. Managing VPCs

Managing VPCs

A network access control list (ACL) is an access control policy system for one or more subnets. Based on inbound and outbound rules, it determines whether data packets are allowed in or out of any associated subnet. You can add a maximum of 20 VPCs for each file system. A maximum of 400 IP addresses or address segments can be created for the VPCs. When adding a VPC, the default IP address is automatically added.

If the VPC bound to the file system has been deleted from the VPC console, the IP address/address segment of this VPC in the VPC list of the file system still can be seen as activated. However, this VPC cannot be used any longer and you are advised to delete the VPC from the list.

For more information about VPC, see the Virtual Private Cloud User Guide.


  1. Log in to the management console and select Scalable File Service.
  2. In the file system list, click the name of the target file system to go to the VPC authorization page.
  3. If no VPCs are available, apply for one. You can add multiple VPCs for a file system. Click Add Authorized VPC and the Add Authorized VPC dialog box is displayed, as shown in Figure 1.

    You can select multiple VPCs from the drop-down list.

    Figure 1 Adding authorized VPCs

  4. Click OK. A successfully added VPC can be displayed in the list. When you add a VPC, the default IP address is automatically added. The default read/write permission is read/write, the default user permission is no_all_squash, and the default root permission is no_root_squash.
  5. View the VPC information in the VPC list. For details about the parameters, see Table 1.

    Table 1 Parameter description




    Name of the added VPC, for example: vpc-4040.

    Authorized Addresses/Segments

    The number of added IP addresses or IP address segments.


    The value can be Add or Delete. Add: Adds an authorized VPC. This operation configures the IP address, read/write permission, user permission, user root permission, and priority. For details, see Table 2. Delete: Deletes this VPC.

  6. Click on the left of the VPC name to view details about the IP addresses/segments added to this VPC. You can Add, Edit, and Delete IP addresses/segments. In the Operation column of the target VPC, click Add. The Add Authorized Address/Segment dialog box is displayed, as shown in Figure 2. Table 2 describes the parameters to be added.

    Figure 2 Adding an authorized address or segment
    Table 2 Parameter description



    Authorized Address/Segment

    • Only one IPv4 address or address segment can be entered.
    • The entered IPv4 address or address segment must be valid and cannot be an IP address or address segment starting with 0 except The value indicates any IP address in the VPC. In addition, the IP address or address segment cannot start with 127 or 224 to 255, for example,,, or This is because IP addresses or address segments starting with 224 to 239 are class D addresses and they are used for multicast. IP addresses or address segments starting with 240 to 255 are class E addresses and they are used for research. If an invalid IP address or address segment is used, the access rule may fail to be added or the added access rule cannot take effect.
    • Multiple addresses separated by commas (,), such as, are not allowed.
    • An address segment, for example, to, needs to be in the mask format like Other formats such as are not supported. The number of bits in a subnet mask must be an integer ranging from 0 to 31. The number of bits 0 is valid only in

    Read&Write Permissions

    The value can be Read&Write or Read-only. The default value is Read&Write.

    User Permission

    Specifies whether to retain the UID and GID of the shared directory. The default value is no_all_squash.

    • all_squash: The UID and GID of a shared file are mapped to user nobody, which is applicable to public directories.
    • no_all_squash: The UID and GID of a shared directory are retained.

    User Root Permission

    Specifies whether to allow the root permission of the client. The default value is no_root_squash.

    • root_squash: Clients cannot access as the root user. When a client accesses as the root user, the user is mapped to the nobody user.
    • no_root_squash: Clients are allowed to access as the root user that has full control and access permissions of the root directories.


    An integer ranging from 0 to 100. 0 indicates the highest priority, and 100 indicates the lowest priority. In the same VPC, the permission of the IP address or address segment with the highest priority is preferentially used. If some IP addresses or address segments are of the same priority, the permission of the recently added or modified one prevails. For example, if the IP address for mounting is and both (read/write) with priority 100 and (read-only) with priority 50 meet the requirements, the permission of (read-only) with priority 50 prevails. That is, if there is no other authorized priority, the permission of all IP addresses in the segment, including, is read-only.


    For an ECS in VPC A, its IP addresses can be successfully added to the authorized IP address list of VPC B, but the file system of VPC B cannot be mounted to this ECS. The VPC used by the ECS and the file system must be the same one.