Dear Alibaba Cloud users, to provide you with a higher-quality load balancing service, Alibaba Cloud will upgrade its Application Load Balancer (ALB) instances starting from 00:00:00, February 25, 2025 (Beijing time). After the upgrade, ALB instances will no longer be differentiated by IP mode and will leverage the VIP auto-scaling capability to achieve a performance of 1 million QPS for a single instance.
Changes
Starting from 00:00:00 on February 25, 2025 (Beijing Time), new instances will use the upgraded Application Load Balancer (ALB) by default. In the meantime, if you want to use upgraded ALB instances, submit an application. For more information, see ALB Quotas.
ALB instances created before 00:00:00 on February 25, 2025 (Beijing time) will not be affected, except for instances created from self-service applications. For upgrades to existing instances, we will proactively notify you and complete the process in the background.
Before and after comparison
Item | After | Before |
IP mode | No longer differentiates between IP modes. Uses VIP auto-scaling to achieve a performance of up to 1 million QPS per instance. | Differentiates between static and dynamic IP modes. VIP auto-scaling is not available. Achieving 1 million QPS per instance requires dynamically scaling the number of IP addresses. |
Health check and origin IP address | Uses a private IP address from the CIDR block of the instance's vSwitch by default. | Uses the 100.64.0.0/10 CIDR block by default, which can cause address conflicts in cross-region scenarios. |
Impact
An ALB instance allocates three IP addresses from each specified vSwitch: one VIP for serving traffic and two local IP addresses for communicating with backend servers and performing health checks. If a vSwitch has insufficient IP addresses, instance creation fails with an error. For more information, see Create and manage ALB instances.
The health check uses a private IP address from the CIDR block of the instance's vSwitch. If you have security policies, such as iptables rules, configured on your backend servers, make sure to allow traffic from this CIDR block. For more information, see Troubleshoot ALB health check issues.
Upgraded ALB instances provide the following additional features:
IP-based server groups support IPv6, allowing them to manage backend services with both IPv4 and IPv6 addresses.
QUIC listeners can use the X-Forwarded-For header to retrieve the client source IP address.
ALB supports security groups and access control lists (ACLs) to control inbound traffic.
You can add SLB instances as backends to an IP-based server group within the same VPC.
This upgrade incurs no additional charges.
The upgrade cannot be rolled back.
Contact us
This upgrade will not impact your business. If you have questions or need assistance, submit a ticket or contact your account manager. Thank you for using Alibaba Cloud!