On CLB purchase page, you can select CLB instances of different attributes. This document describes how to purchase instances based on business scenarios.
CLB instances can be classified into two types: CLB (formerly "application CLB") and Classic CLB. CLB covers all features of Classic CLB. Based on product features and performance, we recommend you use CLB. For detailed comparison, please see Instance Types.
If you need to use CLB to distribute requests from the public network, please select "Public Network".
Public network CLB instances obtain requests from the client via the internet and distribute them to the bound real servers. After you create a public network CLB instance, Tencent Cloud will assign it a VIP address to be resolved by DNS server. Public network CLB allows you to add CNAME and A records and map them to custom domain names. VIPs of public network CLB instances are fixed BGP public network IPs. They can receive HTTP, HTTPS, TCP, UDP, and other requests from the server.
If you need to use CLB to distribute requests from private networks, please select "Private Network".
Both the client and server of private network CLB are in Tencent Cloud and can only be accessed within Tencent Cloud. Access via the internet is not allowed (no public network IP address). Tencent Cloud will assign a private IP to CLB from the network you have selected (such as a VPC). The request traffic will be routed to the backend CVM instance via this IP address.
If your application has multiple layers, such as web servers that can communicate over the internet or database servers that can only communicate over the private network, you can create a framework with both public and private network CLB instances. You can then connect all web servers to the public network CLB instance and database servers to the private network CLB instance. The public network CLB instance receives requests from the internet and sends them to the real servers. After being processed, requests to database will be sent to private network CLB instance, which will then route the requests to database servers.
For CLB IP versions, you can select IPv4, IPv6, or IPv6 NAT64. Currently, IPv6 is fully supported in Beijing, Shanghai, Guangzhou, and Singapore regions.
If you check "Enable Anycast", an Anycast CLB instance will be created. Anycast CLB is a load balancing service that supports cross-region dynamic acceleration. CLB VIP is published in multiple regions. The client connects to the nearest POP and forwards traffic to a CVM instance through the high-speed internet of Tencent Cloud IDC. For more information, see Creating an Anycast Instance.
CLB instance name, which can contain 1–50 characters.
Number of purchased CLB instances.