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    Auto Scaling:CreateAlarm

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    Auto Scaling:CreateAlarm

    Last Updated:Sep 10, 2026

    Creates an event-triggered task.

    Operation description

    Operation description

    • If you create an event-triggered task of the custom monitoring type (MetricType=custom), you must report custom monitoring metrics to CloudMonitor in advance. For more information, see Event-triggered tasks of the custom monitoring type.

    • When you create an event-triggered task, you must specify a monitoring metric (MetricName) and use dimension information (Dimension.N.DimensionKey and Dimension.N.DimensionValue) to determine the aggregation scope of the monitoring metric data in the scaling group. For example, you can specify user_id and scaling_group to aggregate the monitoring metric data of all ECS instances or elastic container instances in the scaling group of the specified user.

      • The monitoring metrics of event-triggered tasks of the custom monitoring type (MetricType=custom) depend on your custom monitoring metrics.

      • For more information about the monitoring metrics supported by event-triggered tasks of the system monitoring type (MetricType=system), see Event-triggered tasks of the system monitoring type.

    Note

    In the dimension information, user_id and scaling_group are automatically populated by the system. You must manually specify device and state. For more information, see the Dimension.N.DimensionKey and Dimension.N.DimensionValue parameters.

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    Test

    RAM authorization

    The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

    • Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.

    • API: The API that you can call to perform the action.

    • Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.

    • Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.

      • For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.

      • For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.

    • Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.

    • Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

    Action

    Access level

    Resource type

    Condition key

    Dependent action

    ess:CreateAlarm

    create

    *ScalingGroup

    acs:ess:{#regionId}:{#accountId}:scalinggroup/{#ScalingGroupId}

    		 None None

    Request parameters

    Parameter

    Type

    Required

    Description

    Example
    RegionId

    string

    Yes

    The region ID of the scaling group.

    cn-hangzhou
    Name

    string

    No

    The name of the event-triggered task.

    TestAlarmTask
    Description

    string

    No

    The description of the event-triggered task.

    Test alarm task.
    ScalingGroupId

    string

    Yes

    The ID of the scaling group associated with the event-triggered task.

    asg-bp18p2yfxow2dloq****
    MetricName

    string

    No

    The name of the monitoring metric. Valid values vary based on the monitoring type of the event-triggered task:

    • If the event-triggered task is of the custom monitoring type (MetricType=custom), valid values are your custom monitoring metrics.

    • If the event-triggered task is of the system monitoring type (MetricType=system), valid values:

      • CpuUtilization: (ECS) CPU utilization (%).

      • ConcurrentConnections: (ECS) number of concurrent connections to an ECS instance.

      • IntranetTx: (ECS) outbound traffic over the internal network (Kbit/min).

      • IntranetRx: (ECS) inbound traffic over the internal network (Kbit/min).

      • VpcInternetTx: (ECS) outbound traffic over the Internet (Kbit/min).

      • VpcInternetRx: (ECS) inbound traffic over the Internet (Kbit/min).

      • SystemDiskReadBps: (ECS) system cloud disk read BPS (byte/s).

      • SystemDiskWriteBps: (ECS) system cloud disk write BPS (byte/s).

      • SystemDiskReadOps: (ECS) system cloud disk read IOPS (count/s).

      • SystemDiskWriteOps: (ECS) system cloud disk write IOPS (count/s).

      • CpuUtilizationAgent: (Agent) CPU utilization (%).

      • GpuUtilizationAgent: (Agent) GPU utilization (%).

      • GpuMemoryFreeUtilizationAgent: (Agent) GPU memory idle rate (%).

      • GpuMemoryUtilizationAgent: (Agent) GPU memory utilization (%).

      • MemoryUtilization: (Agent) memory utilization (%).

      • LoadAverage: (Agent) average system load.

      • TcpConnection: (Agent) total number of TCP connections.

      • TcpConnection: (Agent) number of established TCP connections.

      • PackagesNetOut: (Agent) number of packets sent by the internal NIC (count/s).

      • PackagesNetIn: (Agent) number of packets received by the internal NIC (count/s).

      • PackagesNetOut: (Agent) number of packets sent by the public NIC (count/s).

      • PackagesNetIn: (Agent) number of packets received by the public NIC (count/s).

      • EciPodCpuUtilization: CPU utilization (%).

      • EciPodMemoryUtilization: memory utilization (%).

      • LoadBalancerRealServerAverageQps: (ALB) average QPS per server in a server group (count/s).

    For more information, see Event-triggered tasks of the system monitoring type.

    CpuUtilization
    MetricType

    string

    No

    The type of the monitoring metric. Valid values:

    • system: uses CloudMonitor system metrics.

    • custom: uses custom metrics reported to CloudMonitor.

    system
    Period

    integer

    No

    The statistical period for the monitoring metric data. Unit: seconds. Valid values:

    • 15

    • 60

    • 120

    • 300

    • 900

    Note

    Only scaling groups of the ECS type support a statistical period of 15 seconds.

    Default value: 300.

    300
    Statistics

    string

    No

    The method used to aggregate the monitoring metric data. Valid values:

    • Average: average value.

    • Minimum: minimum value.

    • Maximum: maximum value.

    Default value: Average.

    Average
    Threshold

    number

    No

    The threshold of the monitoring metrics. An alert is triggered and the scaling rule is executed when the threshold expression is met for the specified number of times.

    80.0
    ComparisonOperator

    string

    No

    The comparison operator between the aggregated value of the monitoring metric and the threshold. This parameter specifies the relationship under which the condition is met. Valid values:

    • The aggregated value is greater than or equal to the threshold. Value: >=.

    • The aggregated value is less than or equal to the threshold. Value: <=.

    • The aggregated value is greater than the threshold. Value: >.

    • The aggregated value is less than the threshold. Value: <.

    Default value: >=.

    >=
    EvaluationCount

    integer

    No

    The number of consecutive times that the threshold expression must be met before the scaling rule is executed. For example, the average CPU utilization must be greater than or equal to 80% for three consecutive statistical periods.

    Default value: 3.

    3
    GroupId

    integer

    No

    The ID of the CloudMonitor application group to which the custom monitoring metric belongs. This parameter is required only when MetricType is set to custom.

    4055401
    Effective

    string

    No

    The effective period of the event-triggered task. By default, the event-triggered task is effective at all times.

    This parameter follows cron expressions. The default format is X X X X X ?, where:

    • X: a placeholder for a field, which represents seconds, minutes, hours, day of month, and month in sequence. X can be a specific value or a special character with logical meaning. For more information about the valid values of X, see Cron expression.

    • ?: specifies no value.

    Note

    The value of this parameter is in the UTC+8 time zone by default. You can add the time zone information TZ=+yy before the cron expression to specify a time zone, where y represents the numeric value of the time zone. For example, TZ=+00 * * 1-2 * * ? specifies that the event-triggered task is effective between 01:00 and 02:59 in the UTC+0 time zone every day.

    Examples:

    • * * * * * ? : effective at all times.

    • * * 17-18 * * ? : effective between 17:00 and 18:59 in the UTC+8 time zone every day.

    • TZ=+00 * * 1-2 * * ?: effective between 01:00 and 02:59 in the UTC+0 time zone every day.

    TZ=+00 * * 1-2 * * ?
    AlarmAction

    array

    No

    The unique identifier of the scaling rule associated with the event-triggered task.

    ari:acs:ess:cn-hangzhou:1406926****:scalingrule/asr-bp163l21e07uhn****

    string

    No

    The unique identifier of the scaling rule associated with the event-triggered task.

    ari:acs:ess:cn-hangzhou:1406926****:scalingrule/asr-bp163l21e07uhn****
    Dimension

    array<object>

    No

    The list of dimensions associated with the monitoring metric.

    object

    No

    The list of dimensions associated with the monitoring metric.

    DimensionKey

    string

    No

    The key of the dimension associated with the monitoring metric. Valid values vary based on the monitoring type of the event-triggered task:

    • If the event-triggered task is of the custom monitoring type (MetricType=custom), you can specify any value.

    • If the event-triggered task is of the system monitoring type (MetricType=system), valid values:

      • user_id: your account ID.

      • scaling_group: the scaling group to be monitored.

      • device: the type of the network interface controller (NIC) device.

      • state: the state of the TCP connection.

      • rulePool: the server group specified for the ALB QPS monitoring metrics node.

    device
    DimensionValue

    string

    No

    The value of the dimension associated with the monitoring metric. Valid values are determined by Dimension.N.DimensionKey:

    • If Dimension.N.DimensionKey is a custom value, meaning the event-triggered task is of the custom monitoring type (MetricType=custom), you can specify any value.

    • If Dimension.N.DimensionKey is a system-specified value, meaning the event-triggered task is of the system monitoring type (MetricType=system), valid values:

      • user_id: automatically populated by the system.

      • scaling_group: automatically populated by the system.

      • device:

        • eth0: for classic network instances, eth0 represents the internal NIC. For VPC-connected instances, only the eth0 NIC exists.

        • eth1: for classic network instances, eth1 represents the public NIC.

      • state:

        • TCP_TOTAL: the total number of TCP connections.

        • ESTABLISHED: the number of established TCP connections.

      • rulePool: the ID of the ALB server group. Example: sgp-xxxxx.

    eth0
    Expression

    array<object>

    No

    The information about multi-metric alert rules.

    object

    No

    The information about multi-metric alert rules.

    MetricName

    string

    No

    The name of the monitoring metric in the multi-metric alert rule. Valid values vary based on the monitoring type of the event-triggered task:

    • If the event-triggered task is of the custom monitoring type (MetricType=custom), valid values are your custom monitoring metrics.

    • If the event-triggered task is of the system monitoring type (MetricType=system), valid values:

      • CpuUtilization: (ECS) CPU utilization (%).

      • ConcurrentConnections: (ECS) number of concurrent connections to an ECS instance.

      • IntranetTx: (ECS) outbound traffic over the internal network (Kbit/min).

      • IntranetRx: (ECS) inbound traffic over the internal network (Kbit/min).

      • VpcInternetTx: (ECS) outbound traffic over the Internet (Kbit/min).

      • VpcInternetRx: (ECS) inbound traffic over the Internet (Kbit/min).

      • SystemDiskReadBps: (ECS) system cloud disk read BPS (byte/s).

      • SystemDiskWriteBps: (ECS) system cloud disk write BPS (byte/s).

      • SystemDiskReadOps: (ECS) system cloud disk read IOPS (count/s).

      • SystemDiskWriteOps: (ECS) system cloud disk write IOPS (count/s).

      • CpuUtilizationAgent: (Agent) CPU utilization (%).

      • GpuUtilizationAgent: (Agent) GPU utilization (%).

      • GpuMemoryFreeUtilizationAgent: (Agent) GPU memory idle rate (%).

      • GpuMemoryUtilizationAgent: (Agent) GPU memory utilization (%).

      • MemoryUtilization: (Agent) memory utilization (%).

      • LoadAverage: (Agent) average system load.

      • TcpConnection: (Agent) total number of TCP connections.

      • TcpConnection: (Agent) number of established TCP connections.

      • PackagesNetOut: (Agent) number of packets sent by the internal NIC (count/s).

      • PackagesNetIn: (Agent) number of packets received by the internal NIC (count/s).

      • PackagesNetOut: (Agent) number of packets sent by the public NIC (count/s).

      • PackagesNetIn: (Agent) number of packets received by the public NIC (count/s).

      • EciPodCpuUtilization: CPU utilization (%).

      • EciPodMemoryUtilization: memory utilization (%).

      • LoadBalancerRealServerAverageQps: (ALB) average QPS per server in a server group (count/s).

    For more information, see Event-triggered tasks of the system monitoring type.

    CpuUtilization
    ComparisonOperator

    string

    No

    The comparison operator between the aggregated value of the monitoring metric and the threshold in the multi-metric alert rule. This parameter specifies the relationship under which the condition is met. Valid values:

    • The aggregated value is greater than or equal to the threshold. Value: >=.

    • The aggregated value is less than or equal to the threshold. Value: <=.

    • The aggregated value is greater than the threshold. Value: >.

    • The aggregated value is less than the threshold. Value: <.

    Default value: >=.

    >=
    Period

    integer

    No

    The statistical period for the monitoring metric data in the multi-metric alert rule. Unit: seconds. Valid values:

    • 15

    • 60

    • 120

    • 300

    • 900

    Note

    Only scaling groups of the ECS type support a statistical period of 15 seconds. Default value: 300.

    900
    Statistics

    string

    No

    The method used to aggregate the monitoring metric data in the multi-metric alert rule. Valid values:

    • Average: average value.

    • Minimum: minimum value.

    • Maximum: maximum value.

    Default value: Average.

    Average
    Threshold

    number

    No

    The threshold of the monitoring metrics in the multi-metric alert rule. An alert is triggered and the scaling rule is executed when the threshold expression is met for the specified number of times.

    40.0
    ExpressionsLogicOperator

    string

    No

    The relationship between multiple metric alert conditions. Valid values:

    • &&: an alert is triggered only when all monitoring metrics meet the alert conditions. An alert is triggered only when all expressions in the multi-metric alert rule evaluate to true.

    • ||: an alert is triggered when any monitoring metric meets the alert condition.

    Default value: &&.

    &&

    Response elements

    Element

    Type

    Description

    Example

    object

    AlarmTaskId

    string

    The ID of the event-triggered task.

    asg-bp1hvbnmkl10vll5****_f95ce797-dc2e-4bad-9618-14fee7d1****
    RequestId

    string

    The request ID.

    473469C7-AA6F-4DC5-B3DB-A3DC0DE3****

    Examples

    Success response

    JSON format

    {
  "AlarmTaskId": "asg-bp1hvbnmkl10vll5****_f95ce797-dc2e-4bad-9618-14fee7d1****",
  "RequestId": "473469C7-AA6F-4DC5-B3DB-A3DC0DE3****"
}

    Error codes

    See Error Codes for a complete list.

    Release notes

    See Release Notes for a complete list.