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Monitoring MongoDB with KubeDB
KubeDB has native support for monitoring via Prometheus. You can use builtin Prometheus scraper or Prometheus operator to monitor KubeDB managed databases. This tutorial will show you how database monitoring works with KubeDB and how to configure Database crd to enable monitoring.
Overview
KubeDB uses Prometheus exporter images to export Prometheus metrics for respective databases. Following diagram shows the logical flow of database monitoring with KubeDB.
When a user creates a database crd with spec.monitor section configured, KubeDB operator provisions the respective database and injects an exporter image as sidecar to the database pod. It also creates a dedicated stats service with name {database-crd-name}-stats for monitoring. Prometheus server can scrape metrics using this stats service.
Configure Monitoring
In order to enable monitoring for a database, you have to configure spec.monitor section. KubeDB provides following options to configure spec.monitor section:
| Field | Type | Uses |
|---|---|---|
spec.monitor.agent | Required | Type of the monitoring agent that will be used to monitor this database. It can be prometheus.io/builtin or prometheus.io/operator. |
spec.monitor.prometheus.exporter.port | Optional | Port number where the exporter side car will serve metrics. |
spec.monitor.prometheus.exporter.args | Optional | Arguments to pass to the exporter sidecar. |
spec.monitor.prometheus.exporter.env | Optional | List of environment variables to set in the exporter sidecar container. |
spec.monitor.prometheus.exporter.resources | Optional | Resources required by exporter sidecar container. |
spec.monitor.prometheus.exporter.securityContext | Optional | Security options the exporter should run with. |
spec.monitor.prometheus.serviceMonitor.labels | Optional | Labels for ServiceMonitor crd. |
spec.monitor.prometheus.serviceMonitor.interval | Optional | Interval at which metrics should be scraped. |
Sample Configuration
A sample YAML for MongoDB crd with spec.monitor section configured to enable monitoring with Prometheus operator is shown below.
apiVersion: kubedb.com/v1alpha2
kind: MongoDB
metadata:
name: sample-mongo
namespace: databases
spec:
version: "4.2.3"
terminationPolicy: WipeOut
configSecret:
name: config
storageType: Durable
storage:
storageClassName: default
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 5Gi
monitor:
agent: prometheus.io/operator
prometheus:
serviceMonitor:
labels:
release: prometheus
exporter:
args:
- --collect.database
env:
- name: ENV_VARIABLE
valueFrom:
secretKeyRef:
name: env_name
key: env_value
resources:
requests:
memory: 512Mi
cpu: 200m
limits:
memory: 512Mi
cpu: 250m
securityContext:
runAsUser: 2000
allowPrivilegeEscalation: false
Here, we have specified that we are going to monitor this server using Prometheus operator through spec.monitor.agent: prometheus.io/operator. KubeDB will create a ServiceMonitor crd in databases namespace and this ServiceMonitor will have release: prometheus label.
One thing to note that, we internally use --collect-all args, if the mongodb exporter version >= v0.31.0 . You can check the exporter version by getting the mgversion object, like this,
kubectl get mgversion -o=jsonpath='{.spec.exporter.image}' 4.2.3
In that case, specifying args to collect something (as we used --collect.database above) will not have any effect.
Next Steps
- Learn how to monitor MongoDB database with KubeDB using builtin-Prometheus
- Learn how to monitor MongoDB database with KubeDB using Prometheus operator.