System events are defined by Alibaba Cloud to record and send you resource information notifications, such as the execution states of O&M tasks, resource exceptions, and changes in the status of resources.
Many Alibaba Cloud services, such as Elastic Compute Service (ECS), ApsaraDB RDS, and Server Load Balancer (SLB), support system events. This topic describes only ECS system events. For information about the system events of other Alibaba Cloud services, see the relevant documentation.
Limits
Retired instance families do not support system events. For more information, see Retired instance types.
Usage scenarios of system events
Notification of risks and exceptions
After system events that are not displayed in the ECS console are triggered, Alibaba Cloud pushes the events to the ECS console. The events include the events that affect the availability and performance of ECS resources, such as SystemMaintenance.Reboot events among scheduled O&M events and InstanceExpiration.Stop events among instance billing events. For specific critical system events, Alibaba Cloud sends additional emails or internal messages. You can handle the events in the ECS console or by calling API operations. We recommend that you handle the system events at the earliest opportunity to ensure resource availability and performance. For more information, see Query and handle ECS system events.
For example, when a subscription instance is about to expire, the ECS console prompts you to renew the instance within a specific period of time to ensure service continuity.
Automated O&M
The states of system events that are displayed in the ECS console are defined to help you understand the execution states of system O&M tasks. Meanwhile, new system events and changes in the status of system events are reported to CloudMonitor. This way, you can build an event-driven automated O&M system based on your business requirements. For more information about the states of events, see the States and windows of system events section in this topic.
NoteEach event state corresponds to a CloudMonitor event. For example, the Executing and Executed states that the InstanceFailure.Reboot ECS event code supports correspond to the Instance:InstanceFailure.Reboot:Executing and Instance:InstanceFailure.Reboot:Executed CloudMonitor events.
Some status change events are not displayed in the ECS console and cannot be handled in the ECS console or by calling API operations. Examples of the events include events that indicate changes in the status of instances and interruptions of preemptible instances. The states of the system events are not defined in ECS. However, the events are still reported to CloudMonitor when the events are triggered. This way, you can build an event-triggered automated O&M system based on your business requirements.
For example, status change events are triggered when you start or stop instances. The events do not indicate risks or exceptions. If you want to log your operations to your system, you can configure event notifications for status change events and use the alert callback feature to write the startup and stop information of instances to operation logs.
System event categories
System events are defined by Alibaba Cloud to record and send you resource information notifications. System events are classified into the categories that are described in the following table based on the causes of events.
For information about the system event categories supported by ECS and how to handle ECS system events, see Summary.
Category | Description | Displayed in the ECS console |
Scheduled O&M events | Alibaba Cloud may need to upgrade host software for security reasons or to predict and handle failure risks that lie in underlying host hardware and software. In these cases, if O&M tasks to be executed by Alibaba Cloud may affect the availability or performance of your ECS resources, Alibaba Cloud triggers and sends scheduled O&M events in advance to notify you of task details, such as execution times, objects, and impacts. After you receive a scheduled O&M event, you can handle the O&M event during an off-peak period within the event execution window to minimize business impacts. Note Scheduled O&M events, also known as proactive O&M events, are based on the O&M experience of Alibaba Cloud on millions of servers, the ability to serve tens of thousands of large enterprise customers, and the cutting-edge machine learning algorithms of Alibaba DAMO Academy to predict and handle failure risks that lie in underlying host hardware or software. When failure risks on the host cannot be prevented, Alibaba Cloud notifies you in advance by using scheduled O&M events. This way, you can switch your business before failures occur. If you do not respond to the scheduled O&M events at the earliest opportunity, your ECS instances may break down or restart when failures occur. | Yes Note When scheduled O&M events are triggered for instances of big data instance families or instance families that are equipped with local SSDs (excluding the i4p instance family), the events are displayed on the Local Disk-based Instance Events page. For information about local disk-based instance events, see O&M scenarios and system events for instances equipped with local disks. |
Unexpected O&M events | This category of system events is triggered when ECS instances restart or break down due to unexpected issues, such as kernel panic, out-of-memory (OOM) errors, or hardware or software failures in underlying hosts. Alibaba Cloud sends the events after they are triggered and restores affected ECS resources at the earliest opportunity. Alibaba Cloud also notifies you of the execution states of system O&M tasks related to the events. Note In most cases, unexpected O&M events refer to sudden downtime or restarts of ECS instances due to unpredictable failures of the underlying hosts or kernel errors in the operating systems of the ECS instances.
| Yes Note When unexpected O&M events are triggered for instances of big data instance families or instance families that are equipped with local SSDs (excluding the i4p instance family), the events are displayed on the Local Disk-based Instance Events page. For information about local disk-based instance events, see O&M scenarios and system events for instances equipped with local disks. |
Local disk-based instance events | This category of system events includes system events that are triggered for local disks and instances equipped with local disks. The system events that are triggered for local disks include system events triggered when local disks are damaged. The system events that are triggered for instances equipped with local disks include system events triggered when instances equipped with local disks fail due to local disk damages or when the hardware or software of underlying hosts fails for instances equipped with local disks. Note Local Disk-based Instance Events are not a system event category and are used only to display scheduled or unexpected O&M events for instances of big data instance families or instance families that are equipped with local SSDs (excluding the i4p instance family) and make the events easy to handle. For more information about local disk-based instance events, see O&M scenarios and system events for instances equipped with local disks. | Yes |
Performance limited events of burstable instances | This category of system events is triggered when burstable instances exhaust their CPU credits and start to run at or near the baseline CPU utilization. The system events may affect instance management, instance O&M, and the operation of applications and result in issues such as slow access and delays. | Yes |
Instance security events | This category of system events is triggered when instances face security threats. For example, instance security events are triggered when instances are under DDoS attacks or when blackhole filtering is triggered for instances. | Yes |
Instance migration events due to upgrades at the underlying layer | This category of system events is triggered when instances need to be migrated from specific regions and zones due to an infrastructure upgrade plan of Alibaba Cloud. You can migrate instances based on the system events. | Yes |
Status change events | This category of system events is triggered when operations, such as Start and Stop, on instances cause changes in the status of the instance lifecycle or when instance attribute changes cause changes in the status of the instance lifecycle or other status changes. Status change events are classified into the following categories:
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System event severities
The following severities are assigned to system events based on the impacts of the system events on the normal operation of instances:
Critical: Critical system events may result in instance unavailability and must be handled at the earliest opportunity. For example, a critical system event is triggered when resources are released due to an overdue payment or when an instance is redeployed due to an instance error.
Warning: Warning system events affect your business. For example, a warning system event is triggered when a burstable instance cannot burst above its performance baseline. You must take note of the events or handle the events when appropriate.
Notification: Notification system events do not affect your business. For example, a notification system event is triggered when a snapshot is created for a disk. You can choose whether to pay attention to notification system events.
States and windows of system events
The following table describes the states defined for system events that are displayed in the ECS console.
For information about the supported states of different system events, see the "CloudMonitor event" columns of tables in Summary.
Event state | Attribute | Description |
Inquiring | Intermediate | The O&M task related to the system event is pending authorization. After you authorize the task to be executed, the event enters the Executing state. |
Scheduled | Intermediate | The O&M task related to the system event is scheduled and pending execution. When the O&M task is executed, the event enters the Executing state. |
Executing | Intermediate | The O&M task related to the system event is being executed. |
Executed | Stable | The O&M task related to the system event is complete. |
Avoided | Stable | The impacts of the system event are prevented because the affected instance is migrated within the user operation window. |
Failed | Stable | The O&M task related to the system event failed. |
Canceled | Stable | The O&M task related to the system event is automatically canceled. |
The following figure shows the typical transitions between event states.
System events have the following windows:
User operation window
The user operation window of a system event starts when the event is sent and ends at the time when the related O&M task is executed as scheduled. You can manually execute the O&M task within the user operation window or wait for the system to automatically execute the task. Take note of the following items about the lengths of user operation windows:
In most cases, the user operation window of a scheduled O&M event ranges from 24 to 48 hours.
NoteThe lengths of user operation windows are unlimited for system events in the Inquiring state. The O&M tasks related to the events can start only after you authorize the tasks to be executed.
In most cases, unexpected O&M system events caused by failures or unauthorized operations do not have a user operation window.
For system events indicating that subscription instances are about to expire, the window is 3 days.
For system events indicating that pay-as-you-go instances are about to be stopped due to overdue payments, the window is less than 1 hour.
Event execution window
The execution window of a system event starts when the related O&M task is executed and ends when the task is complete. Take note of the following items about the lengths of event execution windows:
For system events such as failure recovery events, the window is within 10 minutes.
Unexpected O&M events caused by failures or unauthorized operations have a short event execution window.
Formats of ECS event codes and CloudMonitor event names
ECS event codes and CloudMonitor events follow specific naming conventions for easy understanding.
ECS event codes indicate the event causes and impacts on resources and are in the
<Event cause>.<Event impact>format.CloudMonitor event names indicate resource types, event causes, event impacts on resources, and event states and are in the
<Resource type>:<Event cause>.<Event impact>:<Event state>format.
ECS event codes and CloudMonitor event names may include only some of the preceding information. For example, a CloudMonitor event name of Disk:ErrorDetected:Executing indicates that a disk is damaged and excludes information about the impacts on resources.
The following table describes some examples of ECS event codes and CloudMonitor event names.
An ECS event code of Undefined indicates that ECS events are not displayed in the ECS console and cannot be handled in the ECS console or by calling API operations. For more information about ECS system events, see Summary.
Category | Example ECS event code | Example CloudMonitor event name | Description |
Scheduled O&M events | SystemMaintenance.Reboot | Instance:SystemMaintenance.Reboot:Inquiring |
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Unexpected O&M events | ErrorDetected | Disk:ErrorDetected:Executing |
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Lifecycle state change events | Snapshot:CreateSnapshotCompleted | Snapshot:CreateSnapshotCompleted |
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Operations that can be performed on system events
Operation | Description and references |
Understand system events | To learn about system events and understand the event codes, names, severities, usage scenarios, limits, states, and name formats, see this topic. |
View system events | You can view system events in the ECS or CloudMonitor console or by using Alibaba Cloud CLI.
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Handle system events | For specific critical system events, such as system events that affect the availability and performance of ECS resources, we recommend that you handle the events as suggested in the ECS console or by calling API operations at the earliest opportunity to ensure service availability.
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Monitor system events | To ensure the stability of services that run on ECS instances and automate O&M, we recommend that you configure event notifications to be notified of underlying environment changes. After you configure event notifications, the system uses the notification methods that you specify to send you notifications.
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Modify system event-related settings | You can modify system event-related settings based on your business requirements.
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