Cluster Monitoring with the CockroachDB Operator

Despite CockroachDB’s various , 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.

The CockroachDB operator is in .

Configure Prometheus

Every node of a CockroachDB cluster exports granular timeseries metrics formatted for easy integration with Prometheus, a 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.

If you’re on Hosted GKE, before starting, make sure the email address associated with your Google Cloud account is part of the cluster-admin RBAC group, as shown in .

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

Be sure to specify the latest CoreOS Prometheus Operator version in the following command, in place of this example’s use of version v0.82.0.

kubectl apply \
-f https://raw.githubusercontent.com/prometheus-operator/prometheus-operator/v0.82.0/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

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

Download our Prometheus manifest:

curl -O https://www.cockroachlabs.com/docs/files/cockroach/cloud/kubernetes/prometheus/prometheus.yaml

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

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:

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 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 to do this.

Download our alertmanager-config.yaml configuration file:

curl -O https://www.cockroachlabs.com/docs/files/cockroach/cloud/kubernetes/prometheus/alertmanager-config.yaml

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

Add this configuration to the Kubernetes cluster as a secret, renaming it to alertmanager.yaml and labeling 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

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.

Use our 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://www.cockroachlabs.com/docs/files/cockroach/cloud/kubernetes/prometheus/alertmanager.yaml

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

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

Add CockroachDB’s starter :

kubectl apply \
-f https://www.cockroachlabs.com/docs/files/cockroach/cloud/kubernetes/prometheus/alert-rules.yaml

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

Ensure that the rules are visible to Prometheus by opening http://localhost:9090/rules. The screen should look like this:
Verify that the TestAlertManager example alert is firing by opening http://localhost:9090/alerts. The screen should look like this:

To remove the example alert:

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

kubectl edit prometheusrules prometheus-cockroachdb-rules

Remove the dummy.rules block and save the file:

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

Monitor the operator

The automatically exposes Prometheus-style metrics that you can monitor to observe its operations. Metrics can be collected from the operator via HTTP requests (port 8080 by default) against the /metrics endpoint. The response will describe the current node metrics, for example:

...
# HELP node_decommissioning Whether a CockroachDB node is decommissioning.
# TYPE node_decommissioning gauge
node_decommissioning{node="cockroachdb-nvq2l"} 0
node_decommissioning{node="cockroachdb-pmp45"} 0
node_decommissioning{node="cockroachdb-q6784"} 0
node_decommissioning{node="cockroachdb-r4wz8"} 0
...

Configure logging

You can use the operator to configure the CockroachDB logging system. This allows you to output logs to such as file or network logging destinations. The logging configuration is defined in a ConfigMap object, using a key named logs.yaml. For example:

apiVersion: v1
data:
  logs.yaml: |
    sinks:
      file-groups:
        dev:
          channels: DEV
          filter: WARNING
kind: ConfigMap
metadata:
  name: logconfig
  namespace: cockroach-ns

The above configuration overrides the and saves debug-level logs (the DEV ) to disk for troubleshooting. The ConfigMap name must match the cockroachdb.crdbCluster.loggingConfigMapName object in the values file used to :

cockroachdb:
  crdbCluster:
    loggingConfigMapName: logconfig

By default, the operator also modifies the with the following:

sinks:
  stderr:
    channels: {INFO: "HEALTH, OPS", WARNING: "STORAGE, DEV"}
      redact: true

This outputs logging events in the channel to a cockroach-stderr.log file.

Example: Configuring a troubleshooting log file on pods

In this example, CockroachDB has already been deployed on a Kubernetes cluster. Override the to output logs to a cockroach-dev.log file.

Create a ConfigMap named logconfig. Note that namespace is set to the cockroach-ns namespace:

apiVersion: v1
data:
  logs.yaml: |
    sinks:
      file-groups:
        dev:
          channels: DEV
          filter: WARNING
kind: ConfigMap
metadata:
  name: logconfig
  namespace: cockroach-ns

For simplicity, also name the YAML file logconfig.yaml.

The ConfigMap key is not related to the ConfigMap name or YAML filename, and must be named logging.yaml.

This configuration outputs DEV logs that have severity to a cockroach-dev.log file on each pod.

Apply the ConfigMap to the cluster:

kubectl apply -f logconfig.yaml

configmap/logconfig created

Add the name of the ConfigMap in loggingConfigMapName to the values file:

cockroachdb:
  crdbCluster:
    loggingConfigMapName: logconfig

Apply the new settings to the cluster:

helm upgrade --reuse-values $CRDBCLUSTER ./cockroachdb-parent/charts/cockroachdb --values ./cockroachdb-parent/charts/cockroachdb/values.yaml -n $NAMESPACE

The changes will be rolled out to each pod.

See the log files available on a pod:

kubectl exec cockroachdb-2 -- ls cockroach-data/logs

cockroach-dev.cockroachdb-2.unknownuser.2022-05-02T19_03_03Z.000001.log
cockroach-dev.log
cockroach-health.cockroachdb-2.unknownuser.2022-05-02T18_53_01Z.000001.log
cockroach-health.log
cockroach-pebble.cockroachdb-2.unknownuser.2022-05-02T18_52_48Z.000001.log
cockroach-pebble.log
cockroach-stderr.cockroachdb-2.unknownuser.2022-05-02T18_52_48Z.000001.log
cockroach-stderr.cockroachdb-2.unknownuser.2022-05-02T19_03_03Z.000001.log
cockroach-stderr.cockroachdb-2.unknownuser.2022-05-02T20_04_03Z.000001.log
cockroach-stderr.log
cockroach.cockroachdb-2.unknownuser.2022-05-02T18_52_48Z.000001.log
cockroach.log
...

View a specific log file:

kubectl exec cockroachdb-2 -- cat cockroach-data/logs/cockroach-dev.log

​Configure Prometheus

​Configure Alertmanager

​Monitor the operator

​Configure logging

​Example: Configuring a troubleshooting log file on pods

Configure Prometheus

Configure Alertmanager

Monitor the operator

Configure logging

Example: Configuring a troubleshooting log file on pods