Use Prometheus Service to monitor a Redis database

Procedure

The following figure shows the process of using Prometheus Service to monitor a Redis database.

Step 1: Deploy an application

To deploy the redis-exporter image to an ACK cluster to capture Redis data, 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 image 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:
      Note Replace <Address> and <Password> with the corresponding values of the Redis database. You can also use the following sample values that are provided by Application Real-Time Monitoring Service (ARMS):

      • Redis address: redis://r-bp167pgqkqh7h25coypd.redis.rds.aliyuncs.com:6379
      • Redis password: Arms1234

      apiVersion: apps/v1 # for versions before 1.8.0 use apps/v1beta1
      kind: Deployment
      metadata:
        name: redis-exporter
        labels:
          app: redis-exporter
      spec:
        replicas: 1
        selector:
          matchLabels:
            app: redis-exporter
        template:
          metadata:
            labels:
              app: redis-exporter
          spec:
            containers:
            - name: redis-exporter
              imagePullPolicy: Always
              env:
              - name: REDIS_ADDR
                value: "<Address>"
              - name: REDIS_PASSWORD
                value: "<Password>"
              - name: REDIS_EXPORTER_DEBUG
                value: "1"
              image: oliver006/redis_exporter
              ports:
              - containerPort: 9121
                name: redis-exporter

   The Deployments page displays the created container group.
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: redis-exporter
        name: redis-exporter
      spec:
        ports:
        - name: redis-exporter
          port: 9121
          protocol: TCP
          targetPort: 9121
        type: NodePort
        selector:
          app: redis-exporter

   The Services page displays the created service.

Step 2: Configure service discovery

To configure service discovery of Prometheus Service to receive data from the Redis database, 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: redis-exporter
     # Enter a namespace.
     namespace: default
   spec:
     endpoints:
     - interval: 30s
       # The Redis Grafana template ID is 763.
       # Enter the value of the Name field for Port of Prometheus Exporter in the service.yaml file.
       port: redis-exporter
       # Enter the value of the Path field for Prometheus Exporter.
       path: /metrics
     namespaceSelector:
       any: true
       # The namespace of demo.
       matchLabels:
         # Enter the value of the Label field in the service.yaml file to find the service.yaml file.
         app: redis-exporter

   The ServiceMonitor tab displays the configured service discovery task.

Step 3: 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 763, which is the ID of the Redis Grafana template provided by Prometheus, in the Import via grafna.com field and click Load next to the field.
   
4. On the Import page, perform the following operations and click Import:
   
   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 prom drop-down list.
   The following figure shows the configured Grafana dashboard.

Step 4: 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.