Help Center/ Virtual Private Cloud/ User Guide/ VPC and Subnet/ VPC/ Creating a VPC and Subnet

Updated on 2024-07-30 GMT+08:00

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Creating a VPC and Subnet

Scenarios

Virtual Private Cloud (VPC) allows you to provision logically isolated virtual private networks for cloud resources, such as cloud servers, containers, and databases.

You can create a VPC, specify a CIDR block, and create one or more subnets for the VPC. A VPC comes with a default route table that enables subnets in the VPC to communicate with each other.

Procedure

Go to the Create VPC page.

On the Create VPC page, set parameters for the VPC and subnets as prompted.

Figure 1 Creating a VPC and subnet

**Table 1** VPC parameter descriptions
Parameter	Description	Example Value
Region	The region where the VPC belongs. Select the region nearest to you to ensure the lowest latency possible.	CN-Hong Kong
Name	The VPC name. The name: Can contain 1 to 64 characters. Can contain letters, digits, underscores (_), hyphens (-), and periods (.).	vpc-test
IPv4 CIDR Block	The IPv4 CIDR block of the VPC. Consider the following when specifying a CIDR block: Number of IP addresses: Reserve sufficient IP addresses for subsequent business growth. IP address ranges: Avoid IP address conflicts if you need to connect a VPC to an on-premises data center or connect two VPCs. When you create a VPC, we recommend that you use the private IPv4 address ranges specified in RFC 1918 as the CIDR block: 10.0.0.0/8-24: The IP address ranges from 10.0.0.0 to 10.255.255.255, and the mask ranges from 8 to 24. 172.16.0.0/12-24: The IP address ranges from 172.16.0.0 to 172.31.255.255, and the mask ranges from 12 to 24. 192.168.0.0/16-24: The IP address ranges from 192.168.0.0 to 192.168.255.255, and the mask ranges from 16 to 24. In addition to the preceding addresses, you can create a VPC with a publicly routable CIDR block that falls outside of the private IPv4 address ranges specified in RFC 1918. However, the following system and public reserved addresses must be excluded: Reserved system CIDR blocks 100.64.0.0/10 214.0.0.0/7 198.18.0.0/15 169.254.0.0/16 Reserved public CIDR blocks 0.0.0.0/8 127.0.0.0/8 240.0.0.0/4 255.255.255.255/32 For details about VPC planning, see VPC and Subnet Planning.	10.0.0.0/8
Enterprise Project	The enterprise project to which the VPC belongs. An enterprise project facilitates project-level management and grouping of cloud resources and users. The name of the default project is default. For details about creating and managing enterprise projects, see the Enterprise Management User Guide.	default
Advanced Settings (Optional) > Tag	The VPC tag. Click to expand the configuration area and set this parameter. Add tags to help you quickly identify, classify, and search for your VPCs. For details, see Managing VPC Tags. NOTE: If your organization has configured tag policies for VPCs, you need to add tags to your VPCs based on the policies. If you add a tag that does not comply with the tag policies, VPCs may fail to be created. Contact your administrator to learn more about tag policies.	Key: vpc_key1 Value: vpc-01
Advanced Settings (Optional) > Description	Supplementary information about the VPC. Click to expand the configuration area and set this parameter. Enter the description about the VPC in the text box as required. The VPC description can contain a maximum of 255 characters and cannot contain angle brackets (< or >).	N/A

**Table 2** Subnet parameter descriptions
Parameter	Description	Example Value
Subnet Name	The subnet name. The name: Can contain 1 to 64 characters. Can contain letters, digits, underscores (_), hyphens (-), and periods (.).	subnet-01
AZ	An AZ is a geographic location with independent power supply and network facilities in a region. AZs are physically isolated, and AZs in the same VPC are interconnected through an internal network. Each region contains multiple AZs. If one AZ is unavailable, other AZs in the same region continue to provide services. By default, all instances in different subnets of the same VPC can communicate with each other and the subnets can be in different AZs. For example, if you have a VPC with two subnets, A01 in AZ 1 and A02 in AZ 2. Subnet A01 and A02 can communicate with each other by default. A cloud resource and its subnet can be in different AZs. For example, a cloud server in AZ 1 can use a subnet in AZ 3. If AZ 3 becomes faulty, cloud servers in AZ 1 can still use the subnet in AZ 3, and your services are not interrupted. Select Central if you want to provision cloud resources on the cloud and run your workloads on the cloud. Select Edge if you want to provision cloud resources to an edge site and run workloads at the edge site. For details about edge sites, see CloudPond. For details, see Region and AZ. You can select an AZ for a subnet only in certain regions. See the available regions on the management console.	AZ1
CIDR Block	The CIDR block of the subnet. This parameter is displayed only in regions where IPv4/IPv6 dual stack is not supported. Set the IPv4 CIDR block of the subnet. For details, see section "IPv4 CIDR Block".	10.0.0.0/24
IPv4 CIDR Block	The IPv4 CIDR block of the subnet. This parameter is displayed only in regions where IPv4/IPv6 dual stack is supported. A subnet is a unique CIDR block with a range of IP addresses in a VPC. Comply with the following principles when planning subnets: Planning CIDR block size: After a subnet is created, the CIDR block cannot be changed. You need to properly plan the CIDR block in advance based on the number of IP addresses required by your service. The subnet CIDR block size cannot be too small. Ensure that the number of available IP addresses in the subnet meets service requirements. Remember that the first and last three addresses in a subnet CIDR block are reserved for system use. For example, in subnet 10.0.0.0/24, 10.0.0.1 is the gateway address, 10.0.0.253 is the system interface address, 10.0.0.254 is used by DHCP, and 10.0.0.255 is the broadcast address. The subnet CIDR block cannot be too large, either. If you use a CIDR block that is too large, you may not have enough CIDR blocks available later for new subnets, which can be a problem when you want to scale out services. Avoiding subnet CIDR block conflicts: Avoid CIDR block conflicts if you need to connect two VPCs or connect a VPC to an on-premises data center. If the subnet CIDR blocks at both ends of the network conflict, create a subnet. A subnet mask can be between the netmask of its VPC CIDR block and /28 netmask. If a VPC CIDR block is 10.0.0.0/16, its subnet mask can between 16 to 28. For details about subnet planning, see VPC and Subnet Planning.	10.0.0.0/24
IPv6 CIDR Block (Optional)	The IPv6 CIDR block of the subnet. This parameter is displayed only in regions where IPv4/IPv6 dual stack is supported. After the IPv6 function is enabled, the system automatically assigns an IPv6 CIDR block to the created subnet. Currently, the IPv6 CIDR block cannot be customized. IPv6 cannot be disabled after the subnet is created. For details, see IPv4 and IPv6 Dual-Stack Network.	-
Associated Route Table	The default route table with which the subnet will be associated. A route table contains a set of routes that are used to control the traffic routing for your subnets in a VPC. Each VPC comes with a default route table. Subnets in the VPC are then automatically associated with the default route table. The default route table ensures that subnets in a VPC can communicate with each other. If the default route table cannot meet your requirements, you can create a custom route table and associate subnets with it. Then, the default route table controls inbound traffic to the subnets, while the custom route table controls outbound traffic from the subnets. For details, see Creating a Custom Route Table.	-
Advanced Settings (Optional) > Gateway	The gateway address of the subnet. Click to expand the configuration area and set this parameter. Retain the default value unless there are special requirements.	10.0.0.1
Advanced Settings (Optional) > DNS Server Address	The DNS server addresses. Click to expand the configuration area and set this parameter. Huawei Cloud private DNS server addresses are entered by default. This allows ECSs in a VPC to communicate with each other and also access other cloud services using private domain names without exposing their IP addresses to the Internet. You can change the default DNS server addresses if needed. This may interrupt your access to cloud services. You can also click Reset on the right to restore the DNS server addresses to the default value. A maximum of two DNS server IP addresses can be configured. Multiple IP addresses must be separated using commas (,).	100.125.x.x
Advanced Settings (Optional) > Domain Name	The domain name. Click to expand the configuration area and set this parameter. Enter domain names (), separated with spaces. A maximum of 254 characters are allowed. A domain name can consist of multiple labels (max. 63 characters each). To access a domain name, you only need to enter the domain name prefix. ECSs in the subnet automatically match the configured domain name suffix. If the domain names are changed, ECSs newly added to this subnet will use the new domain names. If an existing ECS in this subnet needs to use the new domain names, restart the ECS or run a command to restart the DHCP Client service or network service. NOTE: The command for updating the DHCP configuration depends on the ECS OS. The following commands are for your reference. Restart the DHCP Client service: service dhcpd restart Restart the network service: service network restart	test.com
Advanced Settings (Optional) > IPv4 DHCP Lease Time	The period during which a client can use an IP address automatically assigned by the DHCP server. Click to expand the configuration area and set this parameter. This parameter is displayed only in regions where IPv4/IPv6 dual stack is not supported. The period during which a client can use an IP address automatically assigned by the DHCP server. After the lease time expires, a new IP address will be assigned to the client. Limited: Set the DHCP lease time. The unit can be day or hour. Unlimited: The DHCP lease time does not expire. After you change the DHCP lease time on the console, the change is applied automatically when the DHCP lease of an instance (such as ECS) is renewed. You can wait for the system to renew the lease or manually renew the lease. Renewing lease will not change the IP address used by the instance. If you want the new lease time to take effect immediately, manually renew the lease or restart the ECS. For details, see How Do I Make the Changed DHCP Lease Time of a Subnet Take Effect Immediately?	-
Advanced Settings > IPv4 DHCP Lease Time	The period during which a client can use an IPv4 address automatically assigned by the DHCP server. Click to expand the configuration area and set this parameter. This parameter is displayed only in regions where IPv4/IPv6 dual stack is supported. You can set the DHCP lease time of an IPv4 address. The period during which a client can use an IP address automatically assigned by the DHCP server. After the lease time expires, a new IP address will be assigned to the client. Limited: Set the DHCP lease time. The unit can be day or hour. Unlimited: The DHCP lease time does not expire. If the time period is changed, the new lease time takes effect when the instance (such as an ECS) in the subnet is renewed next time. You can wait for the instance to be renewed automatically or manually modify the lease time. If you want the new lease time to take effect immediately, manually renew the lease or restart the ECS. For details, see How Do I Make the Changed DHCP Lease Time of a Subnet Take Effect Immediately?	-
Advanced Settings > IPv6 DHCP Lease Time	The period during which a client can use an IPv6 address automatically assigned by the DHCP server. Click to expand the configuration area and set this parameter. This parameter is displayed in the region where the IPv4/IPv6 dual stack is supported and when IPv6 is enabled. You can set the DHCP lease time of an IPv6 address in the same way as how you do with an IPv4 address.	-
Advanced Settings (Optional) > NTP Server Address	The IP address of the NTP server. Click to expand the configuration area and set this parameter. If you want to add NTP server addresses for a subnet, you can specify NTP Server Address. The IP addresses are added in addition to the default NTP server addresses. If you add or change the NTP server addresses of a subnet, you need to renew the DHCP lease for or restart all the ECSs in the subnet to make the change take effect immediately. If the NTP server addresses have been cleared out, restarting the ECSs will not help. You must renew the DHCP lease for all ECSs to make the change take effect immediately.	192.168.2.1
Advanced Settings (Optional) > Tag	The subnet tag. Click to expand the configuration area and set this parameter. Add tags to help you quickly identify, classify, and search for your subnets. For details, see Managing Subnet Tags. NOTE: If you have configured tag policies for subnets, you need to add tags to your subnets based on the tag policies. If you add a tag that does not comply with the tag policies, subnets may fail to be created. Contact the administrator to learn more about tag policies.	Key: subnet_key1 Value: subnet-01
Advanced Settings (Optional)> Description	Supplementary information about the subnet. Click to expand the configuration area and set this parameter. Enter the description about the subnet in the text box as required. The subnet description can contain a maximum of 255 characters and cannot contain angle brackets (< or >).	N/A