View and manage scheduled events - - Alibaba Cloud Documentation Center

To ensure that Tair provides continuous and stable services, the system regularly generates scheduled O&M events, such as instance migrations and version upgrades. You can view the type, region, procedure, affected instances, considerations, and default switchover time of a scheduled event. You can also modify the scheduled switchover time. In addition, the system sends notifications by email or internal message.

Precautions

In the Scheduled Events section of the Overview page in the console, you can view the number of pending events. A value of 0 indicates that no pending events are available.
In most cases, notifications for system maintenance events such as instance migrations and version upgrades are sent at least three days before execution. Notifications for high-risk vulnerability fixes are sent three or fewer days before execution due to the urgency of these events.
To ensure that you receive relevant notifications, log on to the Message Center, select ApsaraDB Fault or Maintenance Notifications, and then specify a contact. We recommend that you specify an O&M engineer as the contact. You can receive notifications by email, internal message, or the console.
Note
To be notified of pending event updates such as new pending events and task progress at the earliest opportunity, you can configure alert rules for pending events in the CloudMonitor console. For more information, see Subscribe to event notifications .

Procedure

Log on to the Tair console.
In the left-side navigation pane, choose Events > Scheduled Events.
On the Scheduled Events page, view event details.
The details about an event include Instance ID, Event Type, Event Cause, Business Impact, and Scheduled Disconnection Time. For more information about the causes and impacts on business, see Causes and impacts of events.
The system automatically performs a switchover on the related instance at the specified Scheduled Disconnection Time. If the scheduled switchover time is not during off-peak hours, perform the following steps to modify the Scheduled Disconnection Time value.

Optional: Modify the Scheduled Disconnection Time value.

You can use the default switchover time, modify the scheduled switchover time, or configure the periodic switchover time. The system performs the switchover based on the following priority: scheduled switchover time > periodic switchover time > default switchover time.

Type and description of the switchover time

Procedure

Scheduled switchover time

You can adjust the scheduled switchover time of an event based on actual needs.

On the Scheduled Events page, select one or more events.
In the upper-left corner of the Scheduled Events page, click Add Scheduled Event.
In the Add Scheduled Event panel, set the scheduled switchover time.
If you want to immediately perform the switchover, select Earliest Execution Time. After you confirm the settings, the system starts the preparation and immediately performs a switchover after the preparation is complete.
Note
The time specified by Scheduled Disconnection Time cannot be later than the time specified by Set Before.
Check whether the correct events are selected.
- If yes, click Save to save the settings.
- If no, select the correct events on the Scheduled Events page and set the scheduled switchover time again.

Periodic switchover time

After you specify the periodic switchover time, the system performs switchovers for pending events that have not been executed at the scheduled switchover time and events that have no scheduled switchover time specified at the periodic switchover time.

For example, if you set the periodic switchover time to 00:00:00 on Tuesday, the system performs switchovers on multiple instances related to the pending events at the same time. This reduces the impacts caused by the switchovers.

In the upper-left corner of the Scheduled Events page, click Global Scheduler.
In the Global Scheduler panel, specify the periodic switchover time by Week or Month based on your business requirements.
Note
You can view the specified periodic switchover time in the upper-right corner of the Scheduled Events page. If you select None, no periodic switchover time is displayed.
Click Save to save the settings.

Optional: Cancel the scheduled switchover for an event.
Only scheduled events of the Minor Version Update type can be canceled. You can select the Minor Version Update event and click Cancel Scheduled Event in the upper-left corner.

Causes and impacts of events

Cause	Impact	Description
Instance migration Master-replica switchover Cross-zone migration	Service interruption	When a switchover is performed at the scheduled switchover time, you may experience the following impacts. We recommend that you perform the switchover during off-peak hours and make sure that your applications are configured to automatically reconnect to your instance. Single-zone instance: One switchover is performed. Your instance or data shards in your instance that are involved in the switchover experience transient connections and stay in the read-only state for up to 30 seconds until all the data is synchronized. Multi-zone instance: Two switchovers are performed. During the switchovers, your instance or data shards in your instance that are involved in the switchovers experience transient connections and stay in the read-only state for up to 30 seconds until all the data is synchronized. The second switchover switches the master node to the primary zone. This prevents an increase in access latency that may occur when the master node is in the secondary zone. Important During the switchover, you cannot manage your instance by using Data Management (DMS) or Data Transmission Service (DTS). This impact is temporary.
Update of the minor engine version Minor version update for proxy nodes	Service interruption	When a switchover is performed at the scheduled switchover time, you may experience the following impacts. We recommend that you perform the switchover during off-peak hours and make sure that your applications are configured to automatically reconnect to your instance. Single-zone instance: One switchover is performed. Your instance or data shards in your instance that are involved in the switchover experience transient connections and stay in the read-only state for up to 30 seconds until all the data is synchronized. Multi-zone instance: Two switchovers are performed. During the switchovers, your instance or data shards in your instance that are involved in the switchovers experience transient connections and stay in the read-only state for up to 30 seconds until all the data is synchronized. The second switchover switches the master node to the primary zone. This prevents an increase in access latency that may occur when the master node is in the secondary zone. Important During the switchover, you cannot manage your instance by using Data Management (DMS) or Data Transmission Service (DTS). This impact is temporary.
	Differences between minor versions	Different minor versions (kernel versions) have different updates. You must take note of the differences between the current minor version and the minor version to which your instance is updated.

FAQ

For more information, see FAQ about pending events.

Related API operations

API operation	Description
ModifyActiveOperationTask	Modifies the scheduled switchover time for an O&M task of a Tair instance.