Cluster monitoring

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Despite CockroachDB's various built-in safeguards against failure, it is critical to actively monitor the overall health and performance of a cluster running in production and to create alerting rules that promptly send notifications when there are events that require investigation or intervention.

Configure Prometheus

Every node of a CockroachDB cluster exports granular timeseries metrics formatted for easy integration with Prometheus, an open source tool for storing, aggregating, and querying timeseries data. This section shows you how to orchestrate Prometheus as part of your Kubernetes cluster and pull these metrics into Prometheus for external monitoring.

This guidance is based on CoreOS's Prometheus Operator, which allows a Prometheus instance to be managed using built-in Kubernetes concepts.

1. From your local workstation, edit the cockroachdb service to add the prometheus: cockroachdb label:

   $ kubectl label svc cockroachdb prometheus=cockroachdb
   

   service/cockroachdb labeled
   

   This ensures that only the cockroachdb (not the cockroach-public service) is being monitored by a Prometheus job.

   $ kubectl label svc cockroachdb prometheus=cockroachdb
   

   service/cockroachdb labeled
   

   This ensures that only the cockroachdb (not the cockroach-public service) is being monitored by a Prometheus job.

   $ kubectl label svc my-release-cockroachdb prometheus=cockroachdb
   

   service/my-release-cockroachdb labeled
   

   This ensures that there is a Prometheus job and monitoring data only for the my-release-cockroachdb service, not for the my-release-cockroach-public service.

2. Determine the latest version of CoreOS's Prometheus Operator and run the following to download and apply the latest bundle.yaml definition file:

   Note:

   Be sure to specify the latest CoreOS Prometheus Operator version in the following command, in place of this example's use of version v0.58.0.

   $ kubectl apply \
   -f https://raw.githubusercontent.com/prometheus-operator/prometheus-operator/v0.58.0/bundle.yaml \
   --server-side
   

   customresourcedefinition.apiextensions.k8s.io/alertmanagers.monitoring.coreos.com serverside-applied
   customresourcedefinition.apiextensions.k8s.io/podmonitors.monitoring.coreos.com serverside-applied
   customresourcedefinition.apiextensions.k8s.io/probes.monitoring.coreos.com serverside-applied
   customresourcedefinition.apiextensions.k8s.io/prometheuses.monitoring.coreos.com serverside-applied
   customresourcedefinition.apiextensions.k8s.io/prometheusrules.monitoring.coreos.com serverside-applied
   customresourcedefinition.apiextensions.k8s.io/servicemonitors.monitoring.coreos.com serverside-applied
   customresourcedefinition.apiextensions.k8s.io/thanosrulers.monitoring.coreos.com serverside-applied
   clusterrolebinding.rbac.authorization.k8s.io/prometheus-operator serverside-applied
   clusterrole.rbac.authorization.k8s.io/prometheus-operator serverside-applied
   deployment.apps/prometheus-operator serverside-applied
   serviceaccount/prometheus-operator serverside-applied
   service/prometheus-operator serverside-applied
   

3. Confirm that the prometheus-operator has started:

   $ kubectl get deploy prometheus-operator
   

   NAME                  READY   UP-TO-DATE   AVAILABLE   AGE
   prometheus-operator   1/1     1            1           27s
   

4. Download our Prometheus manifest:

   $ curl -O https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/prometheus.yaml
   

   Note:

   By default, this manifest uses the secret name generated by the CockroachDB Kubernetes Operator. If you generated your own certificates and keys when starting CockroachDB, be sure that ca.secret.name matches the name of the node secret you created.

5. Apply the Prometheus manifest. This creates the various objects necessary to run a Prometheus instance:

   $ kubectl apply -f prometheus.yaml
   

   serviceaccount/prometheus created
   clusterrole.rbac.authorization.k8s.io/prometheus created
   clusterrolebinding.rbac.authorization.k8s.io/prometheus created
   servicemonitor.monitoring.coreos.com/cockroachdb created
   prometheus.monitoring.coreos.com/cockroachdb created
   

6. Access the Prometheus UI locally and verify that CockroachDB is feeding data into Prometheus:

   1. Port-forward from your local machine to the pod running Prometheus:

      $ kubectl port-forward prometheus-cockroachdb-0 9090
      

   2. Go to http://localhost:9090 in your browser.

   3. To verify that each CockroachDB node is connected to Prometheus, go to Status > Targets. The screen should look like this:

      

   4. To verify that data is being collected, go to Graph, enter the sys_uptime variable in the field, click Execute, and then click the Graph tab. The screen should like this:

      

   Tip:

   Prometheus auto-completes CockroachDB time series metrics for you, but if you want to see a full listing, with descriptions, port-forward as described in Access the DB Console and then point your browser to http://localhost:8080/_status/vars.

   For more details on using the Prometheus UI, see their official documentation.

Configure Alertmanager

Active monitoring helps you spot problems early, but it is also essential to send notifications when there are events that require investigation or intervention. This section shows you how to use Alertmanager and CockroachDB's starter alerting rules to do this.

1. Download our alertmanager-config.yaml configuration file:

   $ curl -O \
   https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/alertmanager-config.yaml
   

2. Edit the alertmanager-config.yaml file to specify the desired receivers for notifications. Initially, the file contains a placeholder web hook.

3. Add this configuration to the Kubernetes cluster as a secret, renaming it to alertmanager.yaml and labelling it to make it easier to find:

   $ kubectl create secret generic alertmanager-cockroachdb \
   --from-file=alertmanager.yaml=alertmanager-config.yaml
   

   secret/alertmanager-cockroachdb created
   

   $ kubectl label secret alertmanager-cockroachdb app=cockroachdb
   

   secret/alertmanager-cockroachdb labeled
   

   Warning:

   The name of the secret, alertmanager-cockroachdb, must match the name used in the alertmanager.yaml file. If they differ, the Alertmanager instance will start without configuration, and nothing will happen.

4. Use our alertmanager.yaml file to create the various objects necessary to run an Alertmanager instance, including a ClusterIP service so that Prometheus can forward alerts:

   $ kubectl apply \
   -f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/alertmanager.yaml
   

   alertmanager.monitoring.coreos.com/cockroachdb created
   service/alertmanager-cockroachdb created
   

5. Verify that Alertmanager is running:

   1. Port-forward from your local machine to the pod running Alertmanager:

      $ kubectl port-forward alertmanager-cockroachdb-0 9093
      

   2. Go to http://localhost:9093 in your browser. The screen should look like this:

      

6. Ensure that the Alertmanagers are visible to Prometheus by opening http://localhost:9090/status. The screen should look like this:

   

7. Add CockroachDB's starter alerting rules:

   $ kubectl apply \
   -f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/alert-rules.yaml
   

   prometheusrule.monitoring.coreos.com/prometheus-cockroachdb-rules created
   

8. Ensure that the rules are visible to Prometheus by opening http://localhost:9090/rules. The screen should look like this:

   

9. Verify that the TestAlertManager example alert is firing by opening http://localhost:9090/alerts. The screen should look like this:

   

10. To remove the example alert:

    1. Use the kubectl edit command to open the rules for editing:

       $ kubectl edit prometheusrules prometheus-cockroachdb-rules
       

    2. Remove the dummy.rules block and save the file:

       - name: rules/dummy.rules
         rules:
         - alert: TestAlertManager
           expr: vector(1)
       

apiVersion: v1
data:
  logging.yaml: |
    sinks:
      file-groups:
        dev:
          channels: DEV
          filter: WARNING
      fluent-servers:
        ops:
          channels: [OPS, HEALTH, SQL_SCHEMA]
          address: 127.0.0.1:5170
          net: tcp
          redact: true
        security:
          channels: [SESSIONS, USER_ADMIN, PRIVILEGES, SENSITIVE_ACCESS]
          address: 127.0.0.1:5170
          net: tcp
          auditable: true
kind: ConfigMap
metadata:
  name: logconfig
  namespace: cockroach-operator-system

spec:
  logConfigMap: logconfig

sinks:
  stderr:
    channels: OPS
      redact: true