Monitor CockroachDB with Prometheus

CockroachDB generates detailed time series metrics for each node in a cluster. This page shows you how to pull these metrics into Prometheus, an open source tool for storing, aggregating, and querying time series data. It also shows you how to connect Grafana and Alertmanager to Prometheus for flexible data visualizations and notifications.

Before you begin

• Make sure you have already started a CockroachDB cluster, either locally or in a production environment.

• Note that all files used in this tutorial can be found in the monitoring directory of the CockroachDB repository.

Step 1. Install Prometheus

1. Download the 2.x Prometheus tarball for your OS.

2. Extract the binary and add it to your system PATH. This makes it easy to start Prometheus from any shell.

3. Make sure Prometheus installed successfully:

   $ prometheus --version
   

   prometheus, version 2.34.0 (branch: HEAD, revision: 881111fec4332c33094a6fb2680c71fffc427275)
     build user:       root@d80b449ae319
     build date:       20220315-15:04:36
     go version:       go1.17.8
   

Step 2. Configure Prometheus

1. Download the starter Prometheus configuration file for CockroachDB:

   $ wget https://raw.githubusercontent.com/cockroachdb/cockroach/master/monitoring/prometheus.yml \
   -O prometheus.yml
   

   When you examine the configuration file, you'll see that it is set up to scrape the time series metrics of a single, insecure local node every 10 seconds:

   • scrape_interval: 10s defines the scrape interval.
   • metrics_path: '/_status/vars' defines the Prometheus-specific CockroachDB endpoint for scraping time series metrics.
   • scheme: 'http' specifies that the cluster being scraped is insecure.
   • targets: ['localhost:8080'] specifies the hostname and http-port of the Cockroach node to collect time series metrics on.

2. Edit the configuration file to match your deployment scenario:

   Scenario	Config Change
   Multi-node local cluster	Expand the targets field to include 'localhost:<http-port>' for each additional node.
   Production cluster	Change the targets field to include '<hostname>:<http-port>' for each node in the cluster. Also, be sure your network configuration allows TCP communication on the specified ports.
   Secure cluster	Uncomment scheme: 'https' and comment out scheme: 'http'.

3. Create a rules directory and download the aggregation rules and alerting rules for CockroachDB into it:

   $ mkdir rules
   

   $ cd rules
   

   $ wget -P rules https://raw.githubusercontent.com/cockroachdb/cockroach/master/monitoring/rules/aggregation.rules.yml
   

   $ wget -P rules https://raw.githubusercontent.com/cockroachdb/cockroach/master/monitoring/rules/alerts.rules.yml
   

Step 3. Start Prometheus

1. Start the Prometheus server, with the --config.file flag pointing to the configuration file:

   $ prometheus --config.file=prometheus.yml
   

   ts=2022-04-20T18:57:45.857Z caller=main.go:516 level=info msg="Starting Prometheus" version="(version=2.34.0, branch=HEAD, revision=881111fec4332c33094a6fb2680c71fffc427275)"
   ts=2022-04-20T18:57:45.857Z caller=main.go:521 level=info build_context="(go=go1.17.8, user=root@d80b449ae319, date=20220315-15:04:36)"
   ...
   ts=2022-04-20T18:57:45.859Z caller=web.go:540 level=info component=web msg="Start listening for connections" address=localhost:9090
   ...
   ts=2022-04-20T18:57:46.811Z caller=main.go:1142 level=info msg="Loading configuration file" filename=prometheus.yml
   ts=2022-04-20T18:57:46.973Z caller=main.go:1179 level=info msg="Completed loading of configuration file" filename=prometheus.yml totalDuration=162.470967ms db_storage=1.057µs remote_storage=5.151µs web_handler=457ns query_engine=889ns scrape=150.34215ms scrape_sd=74.253µs notify=94.531µs notify_sd=26.921µs rules=11.488407ms tracing=19.58µs
   ts=2022-04-20T18:57:46.973Z caller=main.go:910 level=info msg="Server is ready to receive web requests."
   

2. Point your browser to http://<hostname of machine running prometheus>:9090, where you can use the Prometheus UI to query, aggregate, and graph CockroachDB time series metrics.

   • Prometheus auto-completes CockroachDB time series metrics for you, but if you want to see a full listing, with descriptions, point your browser to http://<hostname of a CockroachDB node>:8080/_status/vars.
   • For more details on using the Prometheus UI, see their official documentation.

Step 4. Send notifications with 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. In step 2, you already downloaded CockroachDB's starter alerting rules. Now, download, configure, and start Alertmanager.

1. Download the latest Alertmanager tarball for your OS.

2. Extract the binary and add it to your system PATH. This makes it easy to start Alertmanager from any shell.

3. Make sure Alertmanager installed successfully:

   $ alertmanager --version
   

   alertmanager, version 0.24.0 (branch: HEAD, revision: f484b17fa3c583ed1b2c8bbcec20ba1db2aa5f11)
     build user:       root@8fd670bfea94
     build date:       20220325-09:24:35
     go version:       go1.17.8
   

4. Edit the Alertmanager configuration file that came with the binary, alertmanager.yml, to specify the desired receivers for notifications. For example, your configuration may resemble:

   route:
     group_by: ['alertname']
     group_wait: 30s
     group_interval: 5m
     repeat_interval: 1h
     receiver: 'web.hook'
   receivers:
     - name: 'web.hook'
       webhook_configs:
         - url: 'http://127.0.0.1:5001/'
   

5. Start the Alertmanager server, with the --config.file flag pointing to the configuration file:

   $ alertmanager --config.file=alertmanager.yml
   

6. Point your browser to http://<hostname of machine running alertmanager>:9093, where you can use the Alertmanager UI to define rules for silencing alerts.

7. Now that Alertmanager is configured and running, you can optionally import pre-existing rules or create your own if you prefer.

Step 5. Visualize metrics in Grafana

Although Prometheus lets you graph metrics, Grafana is a much more powerful visualization tool that integrates with Prometheus easily.

1. Install and start Grafana for your OS.

2. Point your browser to http://<hostname of machine running grafana>:3000 and log into the Grafana UI with the default username/password, admin/admin, or create your own account.

3. Add Prometheus as a datasource, and configure the datasource as follows:

   Field	Definition
   Name	Prometheus
   Default	True
   Type	Prometheus
   Url	http://<hostname of machine running prometheus>:9090
   Access	Direct

4. Download the starter Grafana dashboards for CockroachDB:

   $ wget https://raw.githubusercontent.com/cockroachdb/cockroach/master/monitoring/grafana-dashboards/runtime.json
   # runtime dashboard: node status, including uptime, memory, and cpu.
   

   $ wget https://raw.githubusercontent.com/cockroachdb/cockroach/master/monitoring/grafana-dashboards/storage.json
   # storage dashboard: storage availability.
   

   $ wget https://raw.githubusercontent.com/cockroachdb/cockroach/master/monitoring/grafana-dashboards/sql.json
   # sql dashboard: sql queries/transactions.
   

   $ wget https://raw.githubusercontent.com/cockroachdb/cockroach/master/monitoring/grafana-dashboards/replication.json
   # replicas dashboard: replica information and operations.
   

5. Add the dashboards to Grafana.

See also

• Monitoring and Alerting
• Metrics