Virtual IP Address

A virtual IP address is a private IP address that can be independently assigned from and released to a VPC subnet. You can:

• Bind one or more virtual IP addresses to a cloud server so that you can use either the virtual IP address or private IP address to access the server. If you have multiple services running on a cloud server, you can use different virtual IP addresses to access them.

• Bind a virtual IP address to multiple cloud servers. You can use a virtual IP address and an HA software (such as Keepalived) to set up a high-availability active/standby cluster. If you want to improve service availability and eliminate single points of failure, you can deploy cloud servers in the active/standby pair or deploy one cloud server and multiple standby cloud servers. In this case, the cloud servers can use the same virtual IP address. If the active cloud server goes down, the standby cloud server becomes the active server and continues to provide services.

Generally, cloud servers use private IP addresses for internal network communication. A virtual IP address has the same network access capabilities as a private IP address. You can use either of them to enable layer 2 and layer 3 communications in a VPC, access a different VPC using a peering connection, enable Internet access through EIPs, and connect the cloud and the on-premises servers using VPN connections and Direct Connect connections. Figure 1 describes how private IP addresses, the virtual IP address, and EIPs work together.

• Private IP addresses are used for internal network communication.
• The virtual IP address works with Keepalived to build an HA cluster. ECSs in this cluster can be accessed through one virtual IP address.
• EIPs are used for Internet communication.