Modify the configurations of ALB instances - Server Load Balancer

This topic describes the rules and procedures for modifying the configurations of Application Load Balancer (ALB) instances.

Change the zones where an ALB instance is deployed

The following table describes the limits, effective time, and impacts on billing when you change the zones of an ALB instance.

Limit	Effective time	Impact on billing	Scenario
If an ALB instance is deployed in one or two zones, you cannot reduce the number of zones of the instance. Limits on changing the zones of an Internet-facing ALB instance: The elastic IP addresses (EIPs) allocated to different zones of the same ALB instance must be of the same type. For more information, see What types of EIPs can be associated with ALB instances? You can associate only pay-as-you-go (pay-by-data-transfer) EIPs that are not associated with Internet Shared Bandwidth instances with an ALB instance. After you associate an EIP with an ALB instance, you can associate an Internet Shared Bandwidth instance with the ALB instance in the ALB console. You cannot associate a subscription EIP or a pay-as-you-go EIP that uses the pay-by-bandwidth metering method with an ALB instance.	After you change the zones of an ALB instance, the new zones immediately take effect. If the network latency is high, you may need to wait a few minutes.	If you change the zones of an Internet-facing ALB instance, the EIPs that are associated with the ALB instance may change. You are charged for the EIPs. Check your bills for the actual fees. For more information, see EIP billing.	If the zones of an ALB instance or the EIPs associated with your Internet-facing ALB instance do not meet your business requirements or exceed your business requirements, you can change the zones of the ALB instance.

Log on to the ALB console.
In the top navigation bar, select the region where the ALB instance is deployed.
On the Instances page, find the ALB instance that you want to manage and choose > Modify Zone/Subnet in the Actions column.
In the Modify Zone/Subnet dialog box, select or clear zones and vSwitches and click OK.
- If no vSwitch is available, click Create vSwitch in the drop-down list. For more information, see Create and manage a VPC.
- If you select zones for an Internet-facing ALB instance, you must also assign an EIP to each zone.
- If you select Purchase EIP when you assign an EIP to an Internet-facing ALB instance, a pay-as-you-go EIP that uses the pay-by-data-transfer metering method is created. The EIP uses BGP (Multi-ISP) lines and is protected by Anti-DDoS Origin Basic.

Change the status of zones

Zone status

Zone status	Description	Supported operation
Enabled	The instance is enabled in the current zone and uses the IP address of the zone to forward traffic.	Remove the DNS record Note If only one zone of an ALB instance is in the Enabled state, you cannot remove the DNS record of the zone.
DNS Removed	The DNS record that is created by using the IP address of the current ALB zone is removed.	Restore the DNS record

Remove or restore a DNS record

You can remove or restore the DNS records of the zones of an ALB instance in the ALB console. You can remove or restore DNS records to change the status of zones. This allows you to simulate different scenarios, such as zone disaster recovery.

Limit	Effective time	Impact on billing	Scenario
ALB upgraded instances support the features of removing and restoring DNS records. Note Before the upgrade, ALB instances in static IP mode supported this feature, while ALB instances in dynamic IP mode did not. If only one zone of an ALB instance is in the Enabled state, you cannot remove the DNS record of the zone.	The removal and restoration of DNS records immediately take effect. If the network latency is high, you may need to wait a few minutes.	None. Important After you remove the DNS record of a zone, traffic that accesses the zone through the IP address continues to be forwarded and the LCU consumption is calculated.	You can simulate scenarios such as zone disaster recovery to verify the high availability of ALB.

Log on to the ALB console.
In the top navigation bar, select the region where the ALB instance resides.
On the Instances page in the ALB console, click the ID of the ALB instance in static IP mode.
On the Instance Details tab, perform the following operations in the Zone section as needed:
- Remove a DNS record
  In the Actions column of the zone that you want to manage, click Remove DNS. In the message that appears, confirm the impacts and click Remove DNS.
  Note
  This operation takes effect only for the current ALB instance. Other instances in the zone are not affected.
  If you remove a DNS record, the A record that resolves the ALB domain name to the IP address used in this zone will be removed. Proceed with caution.
  After the DNS record is removed, the zone status changes to DNS Removed and the system stops probing the availability of the IP address.
- Restore the DNS record
  If you want to restore the DNS record of a zone that is in the DNS Removed state, click Resume DNS in the Actions column of the zone. In the message that appears, confirm the impacts and click Resume DNS.
  Note
  After the zone is re-enabled, an A record that resolves the domain name of the ALB instance to the IP address of the zone will be added. Traffic destined for the domain name of the ALB instance is forwarded by using the IP address of the zone.
  After the DNS record is restored, the zone status changes to Enabled and the availability of the IP address is probed.

Change the edition of an ALB instance

ALB provides basic, standard, and WAF-enabled instances. You can change the edition of an ALB instance. When you change the edition of an ALB instance, the ALB instance continues to provide services.

For more information about the features supported by different editions, see Functions and features.
For more information about the quotas of ALB resources, see ALB quotas.

The following table describes the limits, effective time, and impacts on billing when you change the edition of an ALB instance.

Limit	Effective time	Impact on billing	Scenario
You cannot change a standard ALB instance to a basic ALB instance. You can change a WAF-enabled ALB instance to a standard ALB instance. You cannot change a WAF-enabled ALB instance to a basic ALB instance. For more information about the limits and management of WAF-enabled ALB instances, see Activate and manage WAF-enabled ALB instances.	In most cases, the new edition immediately takes effect. If the network latency is high, you may need to wait a few minutes.	After you change the edition of an ALB instance, you are charged different fees. Check your bills for the actual fees. For more information, see ALB billing rules. After you upgrade an ALB instance to a WAF-enabled ALB instance, you are charged a security protection fee for Web Application Firewall (WAF) 3.0. For more information, see Subscription WAF 3.0 instances and Pay-as-you-go WAF 3.0 instances. If no WAF instance is created in your Alibaba Cloud account and you purchase a WAF-enabled ALB instance, a pay-as-you-go WAF 3.0 instance is created.	If the edition of an ALB instance does not meet your business requirements or exceeds your business requirements, you can change the edition of the instance.

Log on to the ALB console.
In the top navigation bar, select the region where the ALB instance is deployed.
On the Instances page, find the instance that you want to manage and choose > Change Specification in the Actions column.
On the Application Load Balancer | Upgrade/Downgrade page, set Edition to Standard or WAF Enabled, select the Terms of Service, and then click Buy Now.
Return to the Instances page and check whether the edition of the ALB instance is updated.

Modify the maximum bandwidth

After you associate an Internet Shared Bandwidth instance with an Internet-facing ALB instance, you can modify the maximum bandwidth of the ALB instance by modifying the maximum bandwidth of the Internet Shared Bandwidth instance.

Note

If an ALB instance is deployed in two zones and is not associated with an Internet Shared Bandwidth instance, the default maximum Internet bandwidth of the ALB instance is 400 Mbit/s. The maximum bandwidth value is not a guaranteed value. It indicates the upper limit of bandwidth and is for reference only. The maximum bandwidth does not support dynamic scaling and cannot be modified.
If your ALB instance is associated with an Internet Shared Bandwidth instance, the maximum bandwidth of the ALB instance is determined by the maximum bandwidth of the Internet Shared Bandwidth instance.
You can create an Internet Shared Bandwidth instance or modify the maximum bandwidth of an existing Internet Shared Bandwidth instance to meet your business requirements. To create an Internet Shared Bandwidth instance or modify the maximum bandwidth of an existing Internet Shared Bandwidth instance, log on to the Internet Shared Bandwidth console.

The following table describes the limits, effective time, and impacts on billing when you associate the EIPs of an Internet-facing ALB instance with an Internet Shared Bandwidth instance.

Limit	Effective time	Impact on billing	Scenario
The line types of the EIPs must be the same as the line type of the Internet Shared Bandwidth instance. Subscription and pay-as-you-go Internet Shared Bandwidth instances are supported.	After you associate an Internet Shared Bandwidth instance with an ALB instance, the Internet Shared Bandwidth instance immediately takes effect. If the network latency is high, you may need to wait a few minutes.	You are charged for the Internet Shared Bandwidth instance. For more information, see Billing overview.	If the maximum bandwidth of an ALB instance does not meet your business requirements, you can associate an Internet Shared Bandwidth instance with the ALB instance in the ALB console.

Log on to the ALB console.
In the top navigation bar, select the region where the ALB instance is deployed.
On the Instances page, find the ALB instance that you want to manage and associate an Internet Shared Bandwidth instance with the ALB instance by using one of the following methods:
- Choose > Associate EIP Bandwidth Plan in the Actions column or click Associate in the Internet Shared Bandwidth column.
- Click the ID of the ALB instance. On the Instance Details tab, find the Billing Information section and click Associate with Internet Shared Bandwidth.
In the Associate EIP Bandwidth Plan dialog box, select an Internet Shared Bandwidth instance and click OK.
If no Internet Shared Bandwidth instance is available, click Purchase Internet Shared Bandwidth in the drop-down list. We recommend that you purchase a pay-as-you-go Internet Shared Bandwidth instance. For more information about how to purchase an Internet Shared Bandwidth instance, see Create an Internet Shared Bandwidth instance.

References

UpdateLoadBalancerZones: changes the zones of an ALB instance.
UpdateLoadBalancerEdition: changes the edition of an ALB instance.
StartShiftLoadBalancerZones: removes a DNS record of an ALB instance.
CancelShiftLoadBalancerZones: restores a DNS record of an ALB instance.
AttachCommonBandwidthPackageToLoadBalancer: associates an Internet Shared Bandwidth instance with an ALB instance.