Connecting MongoDB Exporter

Application Scenario

When using MongoDB, you need to monitor MongoDB running and locate their faults in a timely manner. The Prometheus monitoring function monitors MongoDB running using Exporter in the CCE container scenario. This section describes how to deploy MongoDB Exporter and implement alarm access.

You are advised to use CCE for unified Exporter management.

Prerequisites

A CCE cluster has been created and MongoDB has been installed.
Your service has been connected for Prometheus monitoring and a CCE cluster has also been connected. For details, see Prometheus Instance for CCE.
You have uploaded the mongodb_exporter image to SoftWare Repository for Container (SWR). For details, see Uploading an Image Through a Container Engine Client.

Deploying MongoDB Exporter

Log in to the CCE console.
Click the connected cluster. The cluster management page is displayed.

Perform the following operations to deploy Exporter:

Configure a secret.
In the navigation pane, choose ConfigMaps and Secrets. Then click Create from YAML in the upper right corner of the page. YAML configuration example:
```
apiVersion: v1
kind: Secret
metadata:
    name: mongodb-secret-test
    namespace: default
type: Opaque
stringData:
    datasource: "mongodb://{user}:{passwd}@{host1}:{port1},{host2}:{port2},{host3}:{port3}/admin"  # Corresponding URI.
```
- The password has been encrypted based on Opaque requirements.
- For details about how to configure a secret, see Creating a Secret.

Deploy MongoDB Exporter.

In the navigation pane, choose Workloads. In the upper right corner, click Create Workload. Then select the Deployment workload and select a desired namespace to deploy MongoDB Exporter. YAML configuration example for deploying Exporter:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    k8s-app: mongodb-exporter # Change the value based on service requirements. You are advised to add the MongoDB instance information.
  name: mongodb-exporter # Change the value based on service requirements. You are advised to add the MongoDB instance information.
  namespace: default #Must be the same as the namespace of MongoDB.
spec:
  replicas: 1
  selector:
    matchLabels:
      k8s-app: mongodb-exporter # Change the value based on service requirements. You are advised to add the MongoDB instance information.
  template:
    metadata:
      labels:
        k8s-app: mongodb-exporter # Change the value based on service requirements. You are advised to add the MongoDB instance information.
    spec:
      containers:
        - args:
            - --collect.database       # Enable collection of database metrics.
            - --collect.collection     # Enable collection of metric sets.
            - --collect.topmetrics     # Enable collection of database header metrics.
            - --collect.indexusage     # Enable collection of index usage statistics.
            - --collect.connpoolstats  # Enable collection of MongoDB connection pool statistics.
          env:
            - name: MONGODB_URI
              valueFrom:
                secretKeyRef:
                  name: mongodb-secret-test
                  key: datasource
          image: swr.cn-north-4.myhuaweicloud.com/mall-swarm-demo/mongodb-exporter:0.10.0
          imagePullPolicy: IfNotPresent
          name: mongodb-exporter
          ports:
            - containerPort: 9216
              name: metric-port  # Required when you configure a capture task.
          securityContext:
            privileged: false
          terminationMessagePath: /dev/termination-log
          terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      imagePullSecrets:
        - name: default-secret
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: { }
      terminationGracePeriodSeconds: 30
---
apiVersion: v1
kind: Service
metadata:
  name: mongodb-exporter
spec:
  type: NodePort
  selector:
    k8s-app: mongodb-exporter
  ports:
    - protocol: TCP
      nodePort: 30003
      port: 9216
      targetPort: 9216

For more details about Exporter parameters, see mongodb_exporter.

Check whether MongoDB Exporter is successfully deployed.
1. On the Deployments tab page, click the Deployment created in 3.b. In the pod list, choose More > View Logs in the Operation column. The Exporter is successfully started and its access address is exposed.
1. Perform verification using one of the following methods:
  - Log in to a cluster node and run either of the following commands:
```
curl http://{Cluster IP address}:9216/metrics
```
```
curl http://{Private IP address of any node in the cluster}:30003/metrics
```
  - Access http://{Public IP address of any node in the cluster}:30003/metrics.
    Figure 1 Accessing a cluster node
  - In the instance list, choose More > Remote Login in the Operation column and run the following command:
```
curl http://localhost:9216/metric
```

Collecting Service Data of the CCE Cluster

Add PodMonitor to configure a collection rule for monitoring the service data of applications deployed in the CCE cluster.

In the following example, metrics are collected every 30s. Therefore, you can check the reported metrics on the AOM page about 30s later.

apiVersion: monitoring.coreos.com/v1
kind: PodMonitor
metadata:
  name: mongodb-exporter
  namespace: default
spec:
  namespaceSelector:
    matchNames:
      - default # Namespace where Exporter is located.
  podMetricsEndpoints:
  - interval: 30s
    path: /metrics
    port: metric-port
  selector:
    matchLabels:
      k8s-app: mongodb-exporter

Verifying that Metrics Can Be Reported to AOM

Log in to the AOM 2.0 console.
In the navigation pane on the left, choose Prometheus Monitoring > Instances.
Click the Prometheus instance connected to the CCE cluster. The instance details page is displayed.
On the Metrics tab page of the Service Discovery page, select your target cluster.
Select job {namespace}/MongoDB-exporter to query custom metrics starting with mongodb.

Setting a Dashboard and Alarm Rule on AOM

By setting a dashboard, you can monitor CCE cluster data on the same screen. By setting an alarm rule, you can detect cluster faults and implement warning in a timely manner.

Setting a dashboard
1. Log in to the AOM 2.0 console.
2. In the navigation pane, choose Dashboard. On the displayed page, click Add Dashboard to add a dashboard. For details, see Creating a Dashboard.
3. On the Dashboard page, select a Prometheus instance for CCE and click Add Graph. For details, see Adding a Graph to a Dashboard.
Setting an alarm rule
1. Log in to the AOM 2.0 console.
2. In the navigation pane, choose Alarm Management > Alarm Rules.
3. Click Create Alarm Rule to set an alarm rule. For details, see Creating a Metric Alarm Rule.