Modify ALB instance configurations

Update instance zones

The following table describes the limitations, effective time, billing impact, and use cases for updating an instance's zones.

Limitations	Effective time	Billing impact	Use cases
You cannot remove a zone if the ALB instance has two or fewer zones. The following limitations apply when you add zones to an internet-facing ALB instance: All Elastic IP Addresses (EIPs) associated with an ALB instance's zones must be of the same type. For more information, see What types of EIPs can be associated with an ALB instance?. Before you associate an EIP, make sure that it is not part of an Internet Shared Bandwidth instance. If you need to use an Internet Shared Bandwidth instance, you can add the EIP to it in the load balancing console after the EIP is associated with the ALB instance. You cannot associate subscription EIPs or pay-as-you-go (pay-by-bandwidth) EIPs.	The update takes effect immediately. However, the update may be delayed for several minutes.	Modifying the zones of an internet-facing ALB instance may involve changes to its EIPs, which can affect billing. Your bill will reflect the final costs. For more information, see EIP billing overview.	Update the instance zones or the EIPs for an internet-facing ALB instance if they do not meet your business requirements.

Log on to the ALB console.
In the top navigation bar, select the region where the instance is deployed.
On the Instances page, find the target instance, and in the Operations column, choose > Modify Zone/Subnet.
In the Modify Zone/Subnet dialog box, to add a zone, select its checkbox and a vSwitch, and to remove a zone, clear its checkbox. Then, click OK.
- If no vSwitches are available, click Create vSwitch in the drop-down list. For more information, see Create and manage a Virtual Private Cloud (VPC).
- For an internet-facing ALB instance, you must also assign an EIP when you add a new zone.
- If you select Purchase EIP to assign an EIP to an internet-facing ALB instance, a pay-as-you-go (pay-by-data-transfer) BGP (Multi-ISP) EIP with basic DDoS protection is created.
- When you remove a zone from an internet-facing ALB instance, you can retain the EIPs that ALB automatically created and associated. Anycast EIPs cannot be retained. The retained EIPs are billed on a pay-as-you-go basis. Manually associated EIPs are automatically retained.

Change the zone status

Zone status

Status	Description	Actions
Enabled	The instance is active in this zone, and its VIP forwards traffic normally.	Remove DNS record Note If only one zone of the ALB instance is in the Enabled state, you cannot remove its DNS record or stop the instance in the zone.
DNS Removed	The instance is in the DNS Removed state in this zone. Its IP address is removed from the ALB domain name resolution.	Restore DNS record

DNS record removal and restoration

You can use the load balancing console to remove and restore DNS records for an ALB instance's zones. This allows you to change the zone status to simulate scenarios such as zone-level disaster recovery.

Limitations

Effective time

Billing impact

Use cases

By default, upgraded ALB instances support DNS record removal and restoration.

Note
For ALB instances that are not upgraded, you can remove and restore DNS records only for instances in static IP mode. This feature is not supported in dynamic IP mode.
If only one zone of an ALB instance is in the Enabled state, you cannot remove the DNS record of the zone.

The operation takes effect immediately. However, the update may be delayed for several minutes.

None.

Important

After a DNS record is removed, traffic sent to the VIP in that zone is still forwarded, and you are still charged for the LCUs consumed.

Simulate multi-zone disaster recovery scenarios to verify ALB high availability.

Log on to the ALB console.
In the top navigation bar, select the region where the ALB instance is deployed.
On the ALB Instances page, click the ID of the target instance.
On the Instance Details tab, in the Zone section, perform one of the following operations.
- Remove a DNS record
  In the Operations column of the target zone, click DNS Removed. In the dialog box that appears, confirm the impacts and then click Remove DNS.
  Note
  
  This operation affects only the current ALB instance. Other instances in the zone are not affected.
  
  After the DNS record of a zone is removed, the A record for the zone's IP address is deleted from the ALB domain name resolution. Assess the potential business impact before proceeding.
  After the DNS record is removed, the status of the zone changes to DNS Removed, and health checks for the VIP in the zone stop.
- Restore a DNS record
  
  To restore a zone that is in the DNS Removed state, click Resume DNS in the Operations column of the zone. In the dialog box that appears, confirm the impacts and then click Resume DNS.
  
  Note
  After the zone is re-enabled, the A record that maps to the zone's IP address is added to the ALB domain name resolution. The zone's IP address will then forward traffic for the ALB domain name.
  
  After the DNS record is restored, the status of the zone changes to Enabled, and health checks for the VIP in the zone resume.

Change the instance edition

ALB instances are available in Basic, Standard, WAF-enabled, and Extended editions. You can upgrade an ALB instance's edition without service interruptions.

For more information about the features of each edition, see Functions and features.
For more information about resource quotas, see Quotas.

The following table describes the limitations, effective time, billing impact, and use cases for changing the edition of an instance.

Limitations	Effective time	Billing impact	Use cases
You cannot downgrade a Standard edition ALB instance to the Basic edition. You can downgrade a WAF-enabled edition ALB instance only to the Standard edition. You cannot downgrade it to the Basic edition. For more information about the limitations and management of WAF-enabled instances, see Enable WAF protection for an ALB instance. You cannot change the edition of an Extended edition ALB instance.	The change takes effect immediately. However, the update may be delayed for several minutes.	Changing the edition of an ALB instance affects the instance fees. Your bill will reflect the final costs. For more information, see ALB billing rules. After you upgrade an ALB instance to the WAF-enabled edition, WAF 3.0 protection fees are incurred. For more information, see Subscription WAF 3.0 and Pay-as-you-go WAF 3.0. If you do not have a WAF instance, a pay-as-you-go WAF 3.0 instance is activated after you purchase a WAF-enabled edition ALB instance.	Change the edition of an ALB instance if the current one does not meet your business requirements.

Log on to the ALB console.
In the top navigation bar, select the region where the instance is deployed.
On the Instances page, find the target instance, and in the Operations column, choose > Change Specification.
On the change specification page, set Edition (Instance Fee) to Standard or WAF-enabled, select the terms of service, and then click Buy Now.

Return to the Instances page and find the target instance. In the Edition column, verify that the instance edition is updated.

Adjust maximum public bandwidth

After you add an internet-facing ALB instance to an Internet Shared Bandwidth instance, you can adjust the ALB instance's maximum bandwidth by modifying the bandwidth of the Internet Shared Bandwidth instance.

Note

If an internet-facing ALB instance (deployed in two zones) is not added to an Internet Shared Bandwidth instance, its maximum bandwidth is determined by the maximum bandwidth of the EIPs that are assigned to each zone. The maximum public bandwidth of each zone is the maximum bandwidth of its EIP.

For a single pay-by-data-transfer EIP, the maximum bandwidth is an upper limit and does not represent guaranteed performance. The sum of the maximum bandwidth of all EIPs, which is the theoretical maximum bandwidth of the ALB instance, also does not represent guaranteed performance.
If an ALB instance is added to an Internet Shared Bandwidth instance, its maximum bandwidth is limited by the Internet Shared Bandwidth instance's maximum bandwidth.

The maximum bandwidth of an Internet Shared Bandwidth instance is an upper limit and does not represent guaranteed performance.
You can adjust the maximum bandwidth by creating a new Internet Shared Bandwidth instance or modifying an existing one. To perform these operations, go to the Internet Shared Bandwidth console.

The following table describes the limitations, effective time, billing impact, and use cases for adding an internet-facing ALB instance's EIPs to an Internet Shared Bandwidth instance.

Limitations	Effective time	Billing impact	Use cases
The line type of the EIP must be the same as the line type of the Internet Shared Bandwidth instance. Both subscription and pay-as-you-go Internet Shared Bandwidth instances are supported.	The operation takes effect immediately. However, the update may be delayed for several minutes.	Adding an EIP to an Internet Shared Bandwidth instance incurs fees. For more information, see Billing.	Add an ALB instance to an Internet Shared Bandwidth instance if the current bandwidth is insufficient.

Log on to the ALB console.
In the top navigation bar, select the region where the instance is deployed.
On the Instances page, find the target instance and add it to an Internet Shared Bandwidth instance in one of the following ways:
- In the Operations column, choose > Associate with Internet Shared Bandwidth, or click Associate in the EIP Bandwidth Plan column.
- Click the ID of the target instance. On the Instance Details tab, find the Billing Information section and click Associate with Internet Shared Bandwidth.
In the Associate with EIP Bandwidth Plan dialog box, select the target Internet Shared Bandwidth instance, and click OK.

If no Internet Shared Bandwidth instances are available, click Purchase EIP Bandwidth Plan in the drop-down list to purchase one. We recommend that you purchase a pay-as-you-go Internet Shared Bandwidth instance.

API reference

UpdateLoadBalancerZones: Modifies an ALB instance's zone attributes.
UpdateLoadBalancerEdition: Modifies an ALB instance's edition.
StartShiftLoadBalancerZones: Removes a zone's DNS record.
CancelShiftLoadBalancerZones: Restores a zone's DNS record.
AttachCommonBandwidthPackageToLoadBalancer: Associates an Internet Shared Bandwidth instance with a load balancer instance.