ECS system events - Elastic Compute Service - Alibaba Cloud Documentation Center

ECS system events notify you of O&M tasks, resource exceptions, and status changes—such as instance migration, or maintenance restarts—so you can respond before availability is affected.

Formats of ECS event codes and CloudMonitor event names

ECS system events sync to CloudMonitor, enabling automated O&M workflows. Event codes and CloudMonitor event names follow these formats:

ECS event codes: <Event cause>.<Impact on resource>.
CloudMonitor event names: <Resource type>:<Event cause>.<Impact on resource>:<Event status>.

Note

Not all event codes include every field. For example, Disk:ErrorDetected:Executing omits the impact field because the disk damage itself is the impact.

The following table lists example ECS event codes and CloudMonitor event names.

Note

If the ECS event code is Undefined, the event does not appear in the ECS console and cannot be handled via the console or OpenAPI.

Category	Sample ECS event code	Sample Cloud Monitor event name	Description
Scheduled O&M events	SystemMaintenance.Reboot	Instance:SystemMaintenance.Reboot:Inquiring	Resource type: Instance (ECS instance). Event cause: SystemMaintenance (Alibaba Cloud-initiated O&M task). Impact on resource: Reboot (instance restarts when the task executes). Event status: Inquiring (pending your authorization before the instance restarts).
Unexpected O&M events	ErrorDetected	Disk:ErrorDetected:Executing	Resource type: Disk (cloud disk). Event cause: ErrorDetected (local disk damaged). Event status: Executing (damaged disk not yet repaired).
Lifecycle change events	Snapshot:CreateSnapshotCompleted	Snapshot:CreateSnapshotCompleted	Resource type: Snapshot. Event cause: CreateSnapshotCompleted (snapshot creation finished).

Scheduled O&M events

Important

Restarting an instance from within its OS does not apply the maintenance action. All restart operations in this topic refer to restarts performed in the ECS console or by calling an OpenAPI operation. See Restart an instance or RebootInstance.

Event code	Event name	Event severity level	CloudMonitor event name	Event description and impact	Recommendations for users
SystemMaintenance.Reboot	Instance restart because of system maintenance	Critical	Instance:SystemMaintenance.Reboot:Inquiring: The instance restart for system maintenance is pending authorization Instance:SystemMaintenance.Reboot:Scheduled: The instance restart for system maintenance is scheduled Instance:SystemMaintenance.Reboot:Executing: The instance restart for system maintenance is in progress Instance:SystemMaintenance.Reboot:Executed: The instance restart for system maintenance is complete Instance:SystemMaintenance.Reboot:Avoided: The instance restart for system maintenance is avoided Instance:SystemMaintenance.Reboot:Failed: The instance restart for system maintenance failed Instance:SystemMaintenance.Reboot:Canceled: The scheduled instance restart for system maintenance is canceled (risk mitigated)	Alibaba Cloud detects a potential host failure risk that may cause the instance to restart. The risk has not yet become an actual failure. This event is sent 24 to 48 hours before the scheduled maintenance. Note Failure risks include: Type 1: Potential risks on the host Type 2: The GPU device of the instance is unavailable	Response options: Modify scheduled restart time. Restart the instance yourself. Wait for the system to automatically restart the instance. Note Monitor the event status. If it does not change after you restart the instance, the risk is not mitigated. Wait at least 12 hours, then restart again at an appropriate time. You can modify instance maintenance properties to specify the default action for O&M events. See Modify instance maintenance properties.
SystemMaintenance.Stop	Instance stop because of system maintenance	Critical	Instance:SystemMaintenance.Stop:Scheduled: The instance stop for system maintenance is scheduled Instance:SystemMaintenance.Stop:Executing: The instance stop for system maintenance is in progress Instance:SystemMaintenance.Stop:Executed: The instance stop for system maintenance is complete Instance:SystemMaintenance.Stop:Avoided: The instance stop for system maintenance is avoided Instance:SystemMaintenance.Stop:Failed: The instance stop for system maintenance failed Instance:SystemMaintenance.Stop:Canceled: The instance stop for system maintenance is canceled	Sent 24 to 48 hours before scheduled maintenance when Alibaba Cloud detects a potential host failure risk that may shut down the instance. The risk has not yet become an actual failure.	Response options: Redeploy the instance yourself. Wait for the system to automatically stop the instance, and then perform subsequent actions, such as redeploying the instance. Note You can modify instance maintenance properties to specify the default action for O&M events. See Modify instance maintenance properties.
SystemMaintenance.Redeploy	Instance redeployment because of system maintenance	Critical	Instance:SystemMaintenance.Redeploy:Inquiring: The instance redeployment for system maintenance is pending authorization Instance:SystemMaintenance.Redeploy:Scheduled: The instance redeployment for system maintenance is scheduled Instance:SystemMaintenance.Redeploy:Executing: The instance redeployment for system maintenance is in progress Instance:SystemMaintenance.Redeploy:Executed: The instance redeployment for system maintenance is complete Instance:SystemMaintenance.Redeploy:Avoided: The instance redeployment for system maintenance is avoided Instance:SystemMaintenance.Redeploy:Canceled: The instance redeployment for system maintenance is canceled	Sent 24 to 48 hours before scheduled maintenance when Alibaba Cloud detects a potential host failure risk that may require instance redeployment. The risk has not yet become an actual failure. Important For an instance that uses local SSDs or local HDDs, the data disks are re-initialized and the data on the local disks is cleared.	Back up data and modify /etc/fstab. Then respond as needed: Redeploy the instance yourself. Wait for the system to automatically redeploy the instance. Note Monitor the event status. If it does not change after you redeploy the instance, the risk is not mitigated. Wait at least 12 hours, then redeploy again at an appropriate time. You can modify instance maintenance properties to specify the default action for O&M events. See Modify instance maintenance properties.
SystemMaintenance.IsolateErrorDisk	Damaged disk isolation because of system maintenance	Critical	Instance:SystemMaintenance.IsolateErrorDisk:Inquiring: The damaged disk isolation for system maintenance is pending authorization Instance:SystemMaintenance.IsolateErrorDisk:Executing: The damaged disk isolation for system maintenance is in progress Instance:SystemMaintenance.IsolateErrorDisk:Executed: The damaged disk isolation for system maintenance is complete Instance:SystemMaintenance.IsolateErrorDisk:Avoided: The damaged disk isolation for system maintenance is avoided Instance:SystemMaintenance.IsolateErrorDisk:Failed: The damaged disk isolation for system maintenance failed Instance:SystemMaintenance.IsolateErrorDisk:Canceled: The damaged disk isolation for system maintenance is canceled	Sent immediately when Alibaba Cloud detects software or hardware damage on a local disk of an ECS instance. Important The procedure for handling a damaged local disk varies based on the instance type. For some instance types, the instance must be restarted to isolate the damaged disk. For other instance types, the damaged disk can be isolated and repaired online.	Back up data and modify /etc/fstab. Then authorize disk isolation at an appropriate time. The disk is isolated online without restarting the instance. Note See Scenario ③ for instances with local disks.
SystemMaintenance.ReInitErrorDisk	Damaged disk re-initialization because of system maintenance	Critical	Instance:SystemMaintenance.ReInitErrorDisk:Inquiring: The damaged disk re-initialization for system maintenance is pending authorization Instance:SystemMaintenance.ReInitErrorDisk:Executing: The damaged disk re-initialization for system maintenance is in progress Instance:SystemMaintenance.ReInitErrorDisk:Executed: The damaged disk re-initialization for system maintenance is complete Instance:SystemMaintenance.ReInitErrorDisk:Avoided: The damaged disk re-initialization for system maintenance is avoided Instance:SystemMaintenance.ReInitErrorDisk:Failed: The damaged disk re-initialization for system maintenance failed Instance:SystemMaintenance.ReInitErrorDisk:Canceled: The damaged disk re-initialization for system maintenance is canceled	Sent immediately after Alibaba Cloud detects software or hardware damage on a local disk and replaces it. This typically occurs within five business days after you authorize disk isolation. Important The procedure for handling a damaged local disk varies based on the instance type. For some instance types, the instance must be restarted to isolate the damaged disk. For other instance types, the damaged disk can be isolated and repaired online.	Authorize disk restoration at an appropriate time. The disk is restored online without restarting the instance. Note See Scenario ③ for instances with local disks.
SystemMaintenance.RebootAndIsolateErrorDisk	Instance restart and damaged disk isolation because of system maintenance	Critical	Instance:SystemMaintenance.RebootAndIsolateErrorDisk:Inquiring: The instance restart and damaged disk isolation for system maintenance is pending authorization Instance:SystemMaintenance.RebootAndIsolateErrorDisk:Executing: The instance restart and damaged disk isolation for system maintenance is in progress Instance:SystemMaintenance.RebootAndIsolateErrorDisk:Executed: The instance restart and damaged disk isolation for system maintenance is complete Instance:SystemMaintenance.RebootAndIsolateErrorDisk:Avoided: The instance restart and damaged disk isolation for system maintenance is avoided Instance:SystemMaintenance.RebootAndIsolateErrorDisk:Canceled: The instance restart and damaged disk isolation for system maintenance is canceled	Sent immediately when Alibaba Cloud detects software or hardware damage on a local disk and fails to isolate the disk online. Important The procedure for handling a damaged local disk varies based on the instance type. For some instance types, the instance must be restarted to isolate the damaged disk. For other instance types, the damaged disk can be isolated and repaired online.	Authorize disk isolation at an appropriate time and restart the instance. The disk is isolated offline, requiring a restart. Note See Scenario ③ for instances with local disks.
SystemMaintenance.RebootAndReInitErrorDisk	Instance restart and damaged disk re-initialization because of system maintenance	Critical	Instance:SystemMaintenance.RebootAndReInitErrorDisk:Inquiring: The instance restart and damaged disk re-initialization for system maintenance is pending authorization Instance:SystemMaintenance.RebootAndReInitErrorDisk:Executing: The instance restart and damaged disk re-initialization for system maintenance is in progress Instance:SystemMaintenance.RebootAndReInitErrorDisk:Executed: The instance restart and damaged disk re-initialization for system maintenance is complete Instance:SystemMaintenance.RebootAndReInitErrorDisk:Avoided: The instance restart and damaged disk re-initialization for system maintenance is avoided Instance:SystemMaintenance.RebootAndReInitErrorDisk:Canceled: The instance restart and damaged disk re-initialization for system maintenance is canceled	Sent immediately when Alibaba Cloud detects software or hardware damage on a local disk and fails to restore it online. Important The procedure for handling a damaged local disk varies based on the instance type. For some instance types, the instance must be restarted to isolate the damaged disk. For other instance types, the damaged disk can be isolated and repaired online.	Authorize disk restoration at an appropriate time and restart the instance. The disk is restored offline, requiring a restart. Note See Scenario ③ for instances with local disks.
SystemMaintenance.StopAndRepair	In-place repair event for an instance with local disks	Critical	Instance:SystemMaintenance.StopAndRepair:Inquiring: Instance shutdown for repair Instance:SystemMaintenance.StopAndRepair:Scheduled: The in-place repair of the instance is scheduled Instance:SystemMaintenance.StopAndRepair:Executing: The in-place repair of the instance is in progress Instance:SystemMaintenance.StopAndRepair:Executed: The in-place repair of the instance is complete Instance:SystemMaintenance.StopAndRepair:Avoided: The in-place repair of the instance is avoided	Sent 48 to 168 hours before the scheduled maintenance when Alibaba Cloud detects a hardware failure risk on the host.	Authorize the repair or redeployment of the instance with local disks at an appropriate time. Note See O&M scenarios and system events for instances with local disks.
SystemMaintenance.CleanReleasedDisks	Cleanup event after EBS hot-plug failure	Warning	Instance:SystemMaintenance.CleanReleasedDisks.Inquiring: Querying the status of the cleanup event after a failed EBS hot-plug. Instance:SystemMaintenance.CleanReleasedDisks.Executing: The cleanup event after an EBS hot-plug failure is in progress Instance:SystemMaintenance.CleanReleasedDisks.Executed: The cleanup event after an EBS hot-plug failure is complete Instance:SystemMaintenance.CleanReleasedDisks.Failed: The cleanup event after an EBS hot-plug failure failed	Sent when Alibaba Cloud detects configuration information for released cloud disks (released due to overdue payments) in the OS of an ECS instance.	Authorize Alibaba Cloud to clear the configuration information of the released cloud disks at an appropriate time. Important Alibaba Cloud shuts down the instance at the time you specify, cleans up the disks, and then starts the instance again.

Unexpected O&M events

Event code	Event name	Event severity level	Cloud Monitor event name	Event description and impact	Handling suggestion
SystemFailure.Reboot	Instance restart due to system error	Critical	Instance:SystemFailure.Reboot:Executing: The instance restart due to a system error started Instance:SystemFailure.Reboot:Executed: The instance restart due to a system error ended Instance:SystemFailure.Reboot:Failed: The instance restart due to a system error failed	An ECS instance restarted due to an unexpected software or hardware failure on its host. Common causes: Host failure: The instance restarts due to an unexpected host failure. Network interruption: The instance becomes unreachable because the connected switch goes offline. The instance may not have restarted.	Wait for the instance to automatically restart, then verify that the instance and its applications run correctly. During the restart, Alibaba Cloud migrates the instance to a healthy host. Note You can modify instance maintenance properties to specify the default action for O&M events. See Modify instance maintenance properties.
InstanceFailure.Reboot	Instance restart required due to an operating system error	Critical	Instance:InstanceFailure.Reboot:Scheduled: The instance restart due to an operating system error is scheduled Instance:InstanceFailure.Reboot:Executing: The instance restart due to an operating system error started Instance:InstanceFailure.Reboot:Executed: The instance restart due to an operating system error ended Instance:InstanceFailure.Reboot:Avoided: The instance restart due to an operating system error is avoided	Sent immediately when Alibaba Cloud detects that an ECS instance is down due to an internal OS issue, such as an out-of-memory (OOM) error, blue screen, freeze, continuous serial port log printing, or kernel panic.	Wait for the instance to automatically restart, then verify that the instance and its applications run correctly. You can enable the Kdump service for the operating system to identify the cause of the crash and prevent similar issues from recurring. For more information, see Enable the Kdump service for a Linux instance or Enable the Kernel Memory Dump feature for a Windows instance.
SystemFailure.Stop	Instance stop due to system error	Critical	Instance:SystemFailure.Stop:Executing: The instance stop due to a system error started Instance:SystemFailure.Stop:Executed: The instance stop due to a system error is complete	Sent immediately when Alibaba Cloud detects that an ECS instance is shut down due to a host failure, such as CPU or memory hardware damage.	Wait for the instance to stop, then start it. When you start the instance, Alibaba Cloud migrates the instance to a healthy host. Note You can modify instance maintenance properties to specify the default action for O&M events. See Modify instance maintenance properties.
SystemFailure.Redeploy	Instance redeployment due to system error	Critical	Instance:SystemFailure.Redeploy:Inquiring: The instance redeployment due to a system error is pending authorization Instance:SystemFailure.Redeploy:Executing: The instance redeployment due to a system error is in progress Instance:SystemFailure.Redeploy:Executed: The instance redeployment due to a system error is complete Instance:SystemFailure.Redeploy:Avoided: The instance redeployment due to a system error is avoided Instance:SystemFailure.Redeploy:Canceled: The instance redeployment due to a system error is canceled	Sent immediately when Alibaba Cloud detects that an instance with local disks must be redeployed due to a host failure. Note This type of event is supported only for instances that depend on host hardware, such as instances that have local disks attached or support SGX-based confidential computing.	Back up data and modify /etc/fstab. Then respond as needed: Redeploy the instance yourself. Wait for the system to automatically redeploy the instance. Note You can modify instance maintenance properties to specify the default action for O&M events. See Modify instance maintenance properties.
SystemFailure.Delete	Automatic bill cancellation due to instance creation failure	Critical	Instance:SystemFailure.Delete:Executing: The automatic bill cancellation due to an instance creation failure started Instance:SystemFailure.Delete:Executed: The bill was automatically canceled due to an instance creation failure Instance:SystemFailure.Delete:Avoided: The automatic bill cancellation due to an instance creation failure is avoided	Sent immediately when an instance creation order succeeds but the instance fails to be created.	Wait for the system to release the instance. The instance is typically released within five minutes after creation failure. Note If you have paid for the order, you receive a refund after the instance is released. To increase the success rate of instance creation: Query available resources and private IP addresses in the destination region and zone before creating an instance. For example, call DescribeAvailableResource. Use Auto Provisioning or Auto Scaling to flexibly deliver instances from a larger resource pool.
ErrorDetected	Alert for local disk damage	Critical	Disk:ErrorDetected:Executing: The alert for local disk damage started Disk:ErrorDetected:Executed: The alert for local disk damage ended	Sent immediately when Alibaba Cloud detects unexpected software or hardware damage on a local disk, preventing reads and writes.	Back up data and modify /etc/fstab. Then isolate and restore the damaged disk at an appropriate time. Supported operations vary by instance type: d1, d1ne, d2s, and d2c: Support online isolation, offline isolation, online repair, and redeployment. d3c, d2c, i2, i2g, i2ne, i2gne, i3, and i3g: Support online isolation, offline isolation, and redeployment. i1: Supports redeployment. ebmi2g: Supports authorized repair and redeployment. Note See Scenario ③ for instances with local disks.
Stalled	Disk performance is severely affected	Critical	Disk:Stalled:Executing: The disk performance started to be severely affected Disk:Stalled:Executed: The disk performance has recovered from being severely affected	Sent immediately when Alibaba Cloud detects an I/O hang on a cloud disk attached to an ECS instance, severely affecting disk performance and preventing reads and writes.	Isolate read/write operations on the cloud disk at the application layer, or temporarily remove the instance from SLB.

Instance migration events due to underlying upgrades

Event code	Event name	Event severity level	Cloud Monitor event name	Event description and impact	Handling suggestion
SystemUpgrade.Migrate	Instance migration required due to underlying upgrades	Critical	Undefined	When Alibaba Cloud upgrades the physical infrastructure, instances in the affected region and zone may need migration. This event is sent in advance.	View event details in the ECS console and migrate the instance as prompted. See Instance migration due to underlying upgrades.

Burstable instance performance restriction events

Event code

Event name

Event severity level

Cloud Monitor event name

Event description and impact

Handling suggestion

Instance:BurstablePerformanceRestricted

Burstable instance performance is restricted

Warning

Instance:BurstablePerformanceRestricted: Burstable instance performance is restricted

Sent immediately when the accrued CPU credits of a burstable instance are depleted.

Response options:

For temporary higher performance, enable unlimited mode.
For sustained higher performance, change the instance type to a larger or non-burstable type.

To customize the notification threshold (for example, alert when CPU credits are less than 10 for 10 consecutive minutes), set a threshold-based alert rule in CloudMonitor. See Monitor burstable instances.

Status change events

Event code	Event name	Event severity level	Cloud Monitor event name	Event description and impact	Handling suggestion
Instance:PreemptibleInstanceInterruption	Spot instance interruption notification	Warning	Instance:PreemptibleInstanceInterruption: Spot instance interruption notification	Sent 5 minutes before a spot instance is reclaimed.	Recommendations: Use spot instances for stateless applications, such as scalable web services and big data analytics. Use Auto Provisioning to deliver instances and mitigate reclamation impact. You can also set a CloudMonitor event notification to automatically purchase new spot instances.
Instance:ModifyInstanceSpec.Reboot	Instance restart required for instance type change to take effect	Critical	Instance:ModifyInstanceSpec.Reboot:Scheduled The instance is about to be restarted due to an instance type change Instance:ModifyInstanceSpec.Reboot:Executing The instance is being restarted due to an instance type change Instance:ModifyInstanceSpec.Reboot:Executed The instance type change has taken effect Instance:ModifyInstanceSpec.Reboot:Avoid The instance restart due to an instance type change is avoided	After an instance type change, the instance must restart for the new configuration to take effect. If you do not restart within seven days, the system forcibly restarts the instance.	Recommendations: Modify scheduled restart time. Schedule a restart within seven days after the new order takes effect. Restart the instance yourself to mitigate risks.
Instance:PerformanceModeChange	Performance mode switchover of burstable instance	Warning	Instance:PerformanceModeChange: Performance mode switchover of burstable instance	Generated when a burstable instance switches between unlimited mode and standard mode.	To follow this event, subscribe to system event notifications in CloudMonitor.
Instance:StateChange	Instance status change notification	Information	Instance:StateChange: Instance status change notification	Generated when the instance status changes, for example, from Running to Stopping or from Stopping to Stopped.	To follow this event, subscribe to system event notifications in CloudMonitor.
Instance:AutoReactivateCompleted	Automatic reboot completion	Information	Instance:AutoReactivateCompleted: Automatic reactivation completed	Generated when you pay the overdue bill and the instance automatically restarts.	To follow this event, subscribe to system event notifications in CloudMonitor.
Instance:LiveMigrationAcrossDDH	Instance hot migration between dedicated hosts	Information	Instance:LiveMigrationAcrossDDH: Instance hot migration between dedicated hosts	Generated when an instance is hot migrated.	To follow this event, subscribe to system event notifications in CloudMonitor.
Disk:DiskOperationCompleted	Disk operation completed	Information	Disk:DiskOperationCompleted: Disk operation completed	Generated when a pay-as-you-go disk is manually attached or detached.	To follow this event, subscribe to system event notifications in CloudMonitor.
Disk:ConvertToPostpaidCompleted	Disk converted to pay-as-you-go	Information	Disk:ConvertToPostpaidCompleted: Disk converted to pay-as-you-go	Generated when a subscription disk is converted to pay-as-you-go.	To follow this event, subscribe to system event notifications in CloudMonitor.
Snapshot:CreateSnapshotCompleted	Disk snapshot created	Information	Snapshot:CreateSnapshotCompleted: Disk snapshot created	Generated when a disk snapshot is created.	To follow this event, subscribe to system event notifications in CloudMonitor.
Snapshot:SnapshotDeleted	Snapshot deletion completed event	Information	Snapshot:SnapshotDeleted: Snapshot deletion completed event	Generated when a manual or automatic snapshot is deleted.	None

Instance performance risk events

Event code	Event name	Event severity level	Cloud Monitor event name	Event description and impact	Handling suggestion
Instance:CPUPerformanceReachLimit	Instance CPU performance reaches the upper limit of the instance type	Warning	Instance:CPUPerformanceReachLimit:Executed : Instance CPU performance reaches the upper limit of the instance type	Alibaba Cloud detects that the CPU utilization of the instance has reached 100% or the upper limit of its instance type. Note The event is sent if the CPU upper limit defined for the instance type is reached twice within the last three minutes.	Sustained CPU usage at the instance type limit may affect your business. Adjust your configuration as needed. See Discover and troubleshoot instance issues.
Instance:StoragePerformanceReachLimit	Instance storage performance reaches the upper limit of the instance type	Warning	Instance:StoragePerformanceReachLimit:Executed : Instance storage performance reaches the upper limit of the instance type	Alibaba Cloud detects that the disk bandwidth or IOPS of the instance has reached the upper limit of its instance type. Examples: The cloud disk bandwidth of the instance reaches the upper limit of the instance type. The cloud disk bandwidth of the instance reaches the burst limit of the instance type. The cloud disk IOPS of the instance reaches the upper limit of the instance type. The cloud disk IOPS of the instance reaches the burst limit of the instance type. Note This event is not supported for ECS instances of generations earlier than Generation 6. The event is sent if the storage performance upper limit defined for the instance type is reached twice within the last three minutes.	Sustained storage performance at the instance type limit may affect your business. Adjust your configuration as needed. See Discover and troubleshoot instance issues.
Instance:NetworkPerformanceReachLimit	Instance network performance reaches the upper limit of the instance type	Warning	Instance:NetworkPerformanceReachLimit:Executed : Instance network performance reaches the upper limit of the instance type	Alibaba Cloud detects that the network performance of the instance has reached the upper limit of its instance type. Examples: The inbound public bandwidth of the instance reaches its upper limit. The outbound public bandwidth of the instance reaches its upper limit. The inbound bandwidth of the instance reaches its upper limit. The outbound bandwidth of the instance reaches its upper limit. The inbound bandwidth of the instance reaches its burst limit. The outbound bandwidth of the instance reaches its burst limit. The number of connections for the instance reaches the upper limit of the instance type. Inbound packet loss occurs due to traffic throttling. Outbound packet loss occurs due to traffic throttling. Note The event is sent if the network performance upper limit defined for the instance type is reached twice within the last three minutes.	Sustained network performance at the instance type limit may affect your business. Adjust your configuration as needed. See Discover and troubleshoot instance issues.
Instance:StatusCheckFailed	Instance status check failed	Warning	Instance:StatusCheckFailed:Executing : Instance status check failed is in progress Instance:NetworkPerformanceReachLimit:Executed : Instance status check failed has ended	Alibaba Cloud detects a connectivity exception for the instance. Examples: The status check for the host where the instance resides failed. The status check for the instance operating system failed.	Connectivity exception detected. Troubleshoot promptly. See Diagnose network connectivity.