This topic describes how to use CloudMonitor to monitor NAT gateways. You can use CloudMonitor to monitor NAT gateways and collect monitoring data of NAT gateways in real time. In the NAT Gateway console, you can troubleshoot issues that occur on your NAT gateways based on the monitoring metrics and time sequence curves that are generated by CloudMonitor.

Enhanced NAT gateway

Query monitoring data

  1. Log on to the NAT Gateway console.
  2. In the top navigation bar, select the region where the NAT gateway is deployed.
  3. On the NAT Gateway page, find the NAT gateway that you want to manage and click in the Monitoring column.

    The monitoring metrics vary based on the types of NAT gateways.

    Table 1. Enhanced NAT gateway
    Metric category Metric Description
    Snat Session Monitor SessionActiveConnection The maximum number of concurrent TCP and UDP connections that are supported by the NAT gateway.
    SessionLimitDropConnection The rate of concurrent connections that are dropped due to the limit of concurrent connections to the NAT gateway.
    SessionNewConnection/SessionNewLimitDropConnection SessionNewConnection: the number of TCP and UDP connections that are established to the NAT gateway per second.

    SessionNewLimitDropConnection: the number of new connections that are dropped per second due to the limit of new connections that can be established to the NAT gateway per second.

    SessionNewConnectionWater/SessionNewLimitDropConnectionWater SessionNewConnectionWater: the ratio of established connections to the upper limit of connections.

    SessionNewLimitDropConnectionWater: the ratio of established new connections to the upper limit of new connections.

    Out Internet Monitor BWRateToInside The amount of inbound traffic per second, including the following two metrics:
    • Traffic Rate from the Internet.
    • Traffic Rate to VPC.
    BytesToInside The total amount of inbound traffic, including the following two metrics:
    • Traffic from the Internet.
    • Traffic to VPC.
    PacketsPerSecond The number of inbound packets per second, including the following two metrics:
    • Packet Rate from the Internet.
    • Packet Rate to VPC.
    Packets The total number of inbound packets, including the following two metrics:
    • Packets from the Internet.
    • Packets to VPC.
    Out Vpc Monitor BWRateToOutside The amount of outbound traffic per second, including the following two metrics:
    • Traffic Rate to the Internet.
    • Traffic Rate from VPC.
    BytesToOutside The total amount of outbound traffic, including the following two metrics:
    • Traffic from VPC.
    • Traffic to the Internet.
    PacketsPerSecond The number of outbound packets per second, including the following two metrics:
    • Packet Rate to the Internet.
    • Packet Rate from VPC.
    Packets The number of outbound packets, including the following two metrics:
    • Packets to the Internet.
    • Packets from VPC.
    Table 2. Standard NAT gateway
    Metric Description
    SnatConnection The number of SNAT connections to the NAT gateway per minute.
    SnatConnectionDrop_ConcurrentConnectionLimit The size of a NAT gateway determines the maximum number of SNAT connections supported by the NAT gateway. This metric displays the number of SNAT connections that are dropped when the upper limit of SNAT connections is reached.
    Note This metric is cumulative and the collected statistics cannot be cleared.
    • If the value of this metric continues to increase within a period of time, we recommend that you upgrade your NAT gateway.
    • If the value of this metric remains unchanged within a period of time, the upper limit of SNAT connections is not reached. Therefore, no SNAT connection is dropped.
    SnatConnectionDrop_ConnectionRateLimit The size of a NAT gateway determines the maximum number of new SNAT connections that can be established to the NAT gateway per second. This metric displays the number of new SNAT connections that are dropped when the maximum number of new SNAT connections per second is exceeded.
    Note This metric is cumulative and the collected statistics cannot be cleared.
    • If the value of this metric continues to increase within a period of time, we recommend that you upgrade your NAT gateway.
    • If the value of this metric remains unchanged within a period of time, the upper limit of new SNAT connections per second is not reached. Therefore, no new SNAT connection is dropped.

Query the monitoring data of EIPs that are associated with NAT gateways

  1. Log on to the NAT Gateway console.
  2. In the top navigation bar, select the region where the NAT gateway is deployed.
  3. On the NAT Gateway page, find the NAT gateway that you want to manage, and then click Manage in the Actions column.
  4. Click the Monitor tab.
  5. Click the EIP Monitoring Associated with NAT Service tab to view the monitoring metrics.
    Metric Description
    Inbound Bandwidth The bandwidth for traffic from the Internet to an Elastic Compute Service (ECS) instance. Unit: bit/s.
    Outbound Bandwidth The bandwidth for traffic from ECS instances to the Internet. Unit: bit/s.
    Inbound Packet Rate The number of packets sent from the Internet to ECS instances per second.
    Outbound Packet Rate The number of packets sent from ECS instances to the Internet per second.
    Out Ratelimit Drop Speed The rate of packets that are dropped due to the upper limit of packets that can be transmitted per second.
    InternetInRatePercentage The bandwidth usage of inbound traffic from the Internet to ECS instances.
    InternetOutRatePercentage The bandwidth usage of outbound traffic from ECS instances to the Internet.

Create an alert rule

You can create alert rules to monitor the usage and status of NAT gateways in real time. This ensures the stability of your workloads.

  1. Log on to the CloudMonitor console.
  2. In the left-side navigation pane, choose Alerts > Alert Rules.
  3. On the Threshold Value Alert tab, click Create Alert Rule.
  4. On the Create Alert Rule page, set the parameters for an alert rule.
    Parameter Description
    Product The name of the service that can be monitored by CloudMonitor. Example: enhanced_nat_gateway.
    Resource Range The resources to which the alert rule is applied. Valid values:
    • All Resources: The alert rule is applied to all the instances of the specified service. For example, if you set the Resource Range parameter to All Resources and the alert threshold for CPU utilization to 80% for ApsaraDB for MongoDB, CloudMonitor sends an alert when the CPU utilization of an ApsaraDB for MongoDB instance exceeds 80%. If you set the Resource Range parameter to All Resources, the alert rule is applied to up to 1,000 instances. If the specified service has more than 1,000 instances, you may not receive alerts when the value of the specified metric reaches the threshold. We recommend that you add resources to application groups before you create alert rules.
    • Instances: The alert rule is applied to a specific instance. For example, if you set the Resource Range parameter to Instances and the alert threshold of CPU utilization to 80% for an ECS instance, CloudMonitor sends an alert when the CPU utilization of the ECS instance exceeds 80%.
    Alert Rule Specify the name of the alert rule.
    Rule Description The content of the alert rule. This parameter defines the conditions that trigger an alert. For example, if the condition specifies that the average CPU utilization in 5 minutes is greater than or equal to 90% for three consecutive cycles, CloudMonitor checks whether the condition is met for only three times every 5 minutes.
    Mute for The period during which an alert is muted. This parameter specifies the interval at which an alert notification is sent to the specified contacts if the alert is not cleared.
    Effective Period The period when the alert rule takes effect. The system monitors the metrics and generates alerts only if the alert rule is effective.
    Notification Contact The contact group to which alert notifications are sent.
    Notification Methods

    Email + DingTalk (Info) is selected by default.

    Auto Scaling If you select Auto Scaling, the specified scaling rule is triggered when an alert is generated. You must set the Region, ESS Group, and ESS Rule parameters.
    Log Service If you select Log Service, the alert message is written to Log Service when an alert is generated. You must set the Region, Project, and Logstore parameters.

    For more information about how to create a project and a Logstore, see Quick Start.

    Email Remark The custom remarks that you want to include in the alert notification email.
    HTTP WebHook The URL that can be accessed over the Internet. CloudMonitor sends a POST request to push an alert message to the specified URL. Only HTTP requests are supported.
  5. Click Confirm.