(Optional) Create a Subnet for the VPC¶
Scenarios¶
You can add subnets during VPC creation. If required, you can also create subnets for an existing VPC.
The created subnet is configured with DHCP by default. After an ECS using this VPC starts, the ECS automatically obtains an IP address using DHCP.
Procedure¶
Log in to the management console.
Click
in the upper left corner and select the desired region and project.On the console homepage, under Network, click Virtual Private Cloud.
In the navigation pane on the left, click Virtual Private Cloud.
On the Virtual Private Cloud page, locate the VPC for which a subnet is to be created and click the VPC name.
On the displayed Subnets tab, click Create Subnet.
In the Create Subnet area, set parameters as prompted.
Figure 1 Create Subnet¶
Table 1 Parameter description¶ Parameter
Description
Example Value
Name
Specifies the subnet name.
Subnet
CIDR Block
Specifies the CIDR block for the subnet. This value must be within the VPC CIDR range.
192.168.0.0/24
Gateway
Specifies the gateway address of the subnet.
192.168.0.1
NTP Server Address
Specifies the NTP server IP address. A maximum of four IP addresses can be configured. Multiple IP addresses must be separated using commas (,).
192.168.2.1
Tag
Specifies the subnet tag, which consists of a key and value pair. You can add a maximum of ten tags to each subnet.
The tag key and value must meet the requirements listed in Table 2.
Key: subnet_key1
Value: subnet-01
DNS Server Address
The external DNS server address is used by default. If you need to change the DNS server address, ensure that the configured DNS server address is available.
-Table 2 Subnet tag key and value requirements¶ Parameter
Requirements
Example Value
Key
Cannot be left blank.
Must be unique for each subnet.
Can contain a maximum of 36 characters.
Can contain only the following character types:
Uppercase letters
Lowercase letters
Digits
Special characters, including hyphens (-) and underscores (_)
subnet_key1
Value
Can contain a maximum of 43 characters.
Can contain only the following character types:
Uppercase letters
Lowercase letters
Digits
Special characters, including hyphens (-) and underscores (_)
subnet-01
The external DNS server address is used by default. If you need to change the DNS server address, select Custom for Advanced Settings and configure the DNS server addresses. You must ensure that the configured DNS server addresses are available.
Click OK.
Precautions¶
After a subnet is created, five IP addresses in the subnet will be reserved and cannot be used. For example, in a subnet with CIDR block 192.168.0.0/24, the following IP addresses are reserved:
192.168.0.0: Network address.
192.168.0.1: Gateway address.
192.168.0.253: Reserved for the system interface. This IP address is used by the VPC for external communication.
192.168.0.254: DHCP service address.
192.168.0.255: Network broadcast address.
If you set Advanced Settings to Custom during subnet creation, the reserved IP addresses may be different from the preceding default ones. The system will reserve five IP addresses based on your subnet settings.