To monitor a Go application by using Prometheus Service, you must instrument the Go application to expose data, use Prometheus Service to capture the data, configure a Grafana dashboard to display the data, and then create an alert. This topic describes how to use Prometheus Service to monitor a Go application. In this example, Container Service for Kubernetes (ACK) and Container Registry are also used.

Prerequisites

Before you begin, make sure that the following requirements are met:

Demo

You can also use a demo project to learn how to monitor a Go application by using Prometheus Service. For more information about the demo project, visit GitHub.

Procedure

The following figure shows the process of using Prometheus Service to monitor a Go application.

flow

Step 1: Instrument a Go application

To instrument the Go application to expose data, perform the following steps:

  1. Import the monitoring package to the Go application.
    import (
        "fmt"
        "github.com/prometheus/client_golang/prometheus/promhttp"
        "net/http"
        "strconv"
    )
  2. Associate the HTTP endpoint of Prometheus Service with promhttp.Handler().
    http.Handle(path, promhttp.Handler()) // Initialize an HTTP handler. 

Step 2: Upload the Go application

To build an image for the instrumented Go application and upload the image to an image repository of Container Registry, perform the following steps:

  1. Run the following command to recompile a module:
    mvn clean install -DskipTests
  2. Run the following command to build an image:
    docker build -t <Name of the on-premises temporary Docker image>:<Version number of the on-premises temporary Docker image> . --no-cache
    Example:
    docker build -t prometheus-go-demo:v0 . --no-cache
  3. Run the following command to tag the image:
    sudo docker tag <Name of the on-premises temporary Docker image>:<Version number of the on-premises temporary Docker image> <Domain name of the image repository>/<Namespace>/<Image name>:<Image version number>
    Example:
    sudo docker tag prometheus-go-demo:v0 registry.cn-hangzhou.aliyuncs.com/testnamespace/prometheus-go-demo:v0
  4. Run the following command to upload the image to the image repository:
    sudo docker push <Domain name of the image repository>/<Namespace>/<Image name>:<Image version number>
    Example:
    sudo docker push registry.cn-hangzhou.aliyuncs.com/testnamespace/prometheus-go-demo:v0
    You can view the information about the uploaded application image on the Tags page of the Container Registry console. Image

Step 3: Deploy the Go application

To deploy the Go application to an ACK cluster, perform the following steps:

  1. Log on to the Alibaba Cloud Container Service for Kubernetes console.
  2. In the left-side navigation pane, click Clusters.
  3. On the Clusters page, find the cluster to which you want to deploy the Go application and click Applications in the Actions column.
  4. Create a container group.
    1. In the left-side navigation pane, choose Workloads > Deployments.
    2. On the Deployments page, click Create from YAML in the upper-right corner.
    3. On the Create page, enter the following code in the Template code editor and click Create:
      apiVersion: apps/v1 # for versions before 1.8.0 use apps/v1beta1
      kind: Deployment
      metadata:
        name: prometheus-go-demo
        labels:
          app: go-exporter
      spec:
        replicas: 2
        selector:
          matchLabels:
            app: go-exporter
        template:
          metadata:
            labels:
              app: go-exporter
          spec:
            containers:
            - name: prometheus-go-demo
              imagePullPolicy: Always
              image: <Domain name of the image repository>/<Namespace>/<Image name >:<Image version number>
              ports:
              - containerPort: 8077
                name: arms-go-demo
      Example:
      apiVersion: apps/v1 # for versions before 1.8.0 use apps/v1beta1
      kind: Deployment
      metadata:
        name: prometheus-go-demo
        labels:
          app: go-exporter
      spec:
        replicas: 2
        selector:
          matchLabels:
            app: go-exporter
        template:
          metadata:
            labels:
              app: go-exporter
          spec:
            containers:
            - name: prometheus-go-demo
              imagePullPolicy: Always
              image: registry.cn-hangzhou.aliyuncs.com/fuling/prometheus-go-demo:v0
              ports:
              - containerPort: 8077
                name: arms-go-demo
    The Deployments page displays the created container group. go-exporter
  5. Create a service.
    1. In the left-side navigation pane, choose Services and Ingresses > Services.
    2. On the Services page, click Create Resources in YAML.
    3. On the Create page, enter the following code in the Template code editor and click Create:
      apiVersion: v1
      kind: Service
      metadata:
        labels:
          app: prometheus-go-demo
        name: prometheus-go-demo
      spec:
        ports:
        - name: arms-go-demo
          port: 8077
          protocol: TCP
          targetPort: 8077
        type: NodePort
        selector:
          app: prometheus-go-demo
    The Services page displays the created service. Go service

Step 4: Configure service discovery

To configure service discovery of Prometheus Service to receive data from the Go application, perform the following steps:

  1. Log on to the ARMS console.
  2. In the left-side navigation pane, click Prometheus Monitoring.
  3. In the top navigation bar of the Prometheus Monitoring page, select the region where the ACK cluster resides. Find the cluster and click Settings in the Actions column.
  4. On the Settings page, click the Service Discovery tab. On the Service Discovery tab, click the ServiceMonitor tab.
  5. On the ServiceMonitor tab, click Add ServiceMonitor.
  6. In the Add ServiceMonitor dialog box, enter the following code and click OK:
    apiVersion: monitoring.coreos.com/v1
    kind: ServiceMonitor
    metadata:
      # Enter a unique name.
      name: prometheus-go-demo
      # Enter a namespace.
      namespace: default
    spec:
      endpoints:
      - interval: 30s
        # Enter the value of the Name field for Port of Prometheus Exporter.
        port: arms-go-demo
        # Enter the value of the Path field for Prometheus Exporter.
        path: /metrics
      namespaceSelector:
        any: true
        # The namespace of demo.
      selector:
        matchLabels:
          app: prometheus-go-demo
    The ServiceMonitor tab displays the configured service discovery task. Go service discovery

Step 5: Configure a Grafana dashboard

To configure a Grafana dashboard to display data, perform the following steps:

  1. Go to the homepage of Grafana dashboards.
  2. In the left-side navigation pane, choose + > Import.
  3. On the Import page, enter 6671, which is the ID of the Go Grafana template provided by Prometheus, in the Import via grafna.com field and click Load next to the field.
    Import Grafana Dashboard
  4. On the Import page, perform the following operations and click Import:
    Import Grafana Dashboard with Options
    1. Enter a dashboard name in the Name field.
    2. Select your ACK cluster from the Folder drop-down list.
    3. Select your ACK cluster from the prometheus-apl drop-down list.
    The following figure shows the configured Grafana dashboard. ARMS Prometheus Grafana Go

Step 6: Create an alert

  1. Log on to the ARMS console.
  2. In the left-side navigation pane, click Prometheus Monitoring.
  3. In the top navigation bar, select a region. Then, click the name of the required Kubernetes cluster.
  4. In the left-side navigation pane, choose Alarm configuration beta. Then, click Create Alert in the upper-right corner.
  5. In the Create Alert dialog box, configure the following parameters, and then click OK.
    Note The Time parameter is not supported.
    1. Enter a name in the Rule Name field. Example: alerts for inbound traffic.
    2. Enter an expression that uses a PromQL statement. Example: (sum(rate(kube_state_metrics_list_total{job="kube-state-metrics",result="error"}[5m])) / sum(rate(kube_state_metrics_list_total{job="kube-state-metrics"}[5m]))) > 0.01.
      Notice An error may be reported if a PromQL statement contains a dollar sign ($). You must remove the equal sign (=) and the parameters on both sides of the equal sign (=) from the statement that contains the dollar sign ($). For example, change sum (rate (container_network_receive_bytes_total{instance=~"^$HostIp.*"}[1m])) to sum (rate (container_network_receive_bytes_total[1m])).
    3. In the Labels section, click Create Tag to specify alert tags. The specified tags can be used as options for a dispatch rule.
    4. In the Annotations section, specify a template for alert messages. Click Create Annotation. Set Key to message and Value to {{variable name}} alert message. The specified annotation is in the format of message:{{variable name}} alert notification. Example: message:{{$labels.pod_name}} restart.

      You can customize a variable name or select an existing tag as the variable name. Existing tags:

      • The tags that are carried in the metrics of an alert rule expression.
      • The tags that are created when you create an alert rule. For more information, see Create an alert.
      • The default tags provided by ARMS. The following table describes the default tags.
        Tag Description
        alertname The name of the alert. The format is <Alert name>_<Cluster name>.
        _aliyun_arms_alert_level The level of the alert.
        _aliyun_arms_alert_type The type of the alert.
        _aliyun_arms_alert_rule_id The ID of the alert rule.
        _aliyun_arms_region_id The ID of the region.
        _aliyun_arms_userid The ID of the user.
        _aliyun_arms_involvedObject_type The subtype of the associated object, for example, ManagedKubernetes or ServerlessKubernetes.
        _aliyun_arms_involvedObject_kind The type of the associated object, for example, app or cluster.
        _aliyun_arms_involvedObject_id The ID of the associated object.
        _aliyun_arms_involvedObject_name The name of the associated object.
    Prometheus-Create alarm