// This assembly is included in the following assemblies:
//
// metrics/assembly_metrics-prometheus-deploy.adoc/

[id='proc-metrics-deploying-prometheus-{context}']

= Deploying Prometheus

[role="_abstract"]
Use Prometheus to obtain monitoring data in your Kafka cluster.

You can use your own Prometheus deployment or deploy Prometheus using the xref:assembly-metrics-config-files-{context}[example metrics configuration files] provided by Strimzi.
The example files include a configuration file for a Prometheus deployment and files for Prometheus-related resources:

* `examples/metrics/prometheus-install/prometheus.yaml`
* `examples/metrics/prometheus-install/prometheus-rules.yaml`
* `examples/metrics/prometheus-install/strimzi-pod-monitor.yaml`
* `examples/metrics/prometheus-additional-properties/prometheus-additional.yaml`


The deployment process creates a `ClusterRoleBinding` and discovers an Alertmanager instance in the namespace specified for the deployment.

NOTE: By default, the Prometheus Operator only supports jobs that include an `endpoints` role for service discovery. Targets are discovered and scraped for each endpoint port address. For endpoint discovery, the port address may be derived from service (`role: service`) or pod (`role: pod`) discovery.

.Prerequisites

* Check the xref:ref-metrics-alertmanager-examples-{context}[example alerting rules provided]

.Procedure

. Modify the Prometheus installation file (`prometheus.yaml`) according to the namespace Prometheus is going to be installed into:
+
On Linux, use:
+
[source,shell,subs="+quotes,attributes"]
sed -i 's/namespace: .*/namespace: _my-namespace_/' prometheus.yaml
+
On MacOS, use:
+
[source,shell,subs="+quotes,attributes"]
sed -i '' 's/namespace: .*/namespace: _my-namespace_/' prometheus.yaml

. Edit the `PodMonitor` resource in `strimzi-pod-monitor.yaml` to define Prometheus jobs that will scrape the metrics data from pods.
+
Update the `namespaceSelector.matchNames` property with the namespace where the pods to scrape the metrics from are running.
+
`PodMonitor` is used to scrape data directly from pods for Apache Kafka, ZooKeeper, Operators, the Kafka Bridge and Cruise Control.

. Edit the `prometheus.yaml` installation file to include additional configuration for scraping metrics directly from nodes.
+
The Grafana dashboards provided show metrics for CPU, memory and disk volume usage, which come directly from the Kubernetes cAdvisor agent and kubelet on the nodes.
+
The Prometheus Operator does not have a monitoring resource like `PodMonitor` for scraping the nodes, so the `prometheus-additional.yaml` file contains the additional configuration needed.

.. Create a `Secret` resource from the configuration file (`prometheus-additional.yaml` in the `examples/metrics/prometheus-additional-properties` directory):
+
[source,shell,subs="+quotes,attributes"]
kubectl apply -f prometheus-additional.yaml

.. Edit the `additionalScrapeConfigs` property in the `prometheus.yaml` file to include the name of the `Secret` in the `prometheus-additional.yaml` file.

. Deploy the Prometheus resources:
+
[source,shell,subs="+quotes,attributes"]
kubectl apply -f strimzi-pod-monitor.yaml
kubectl apply -f prometheus-rules.yaml
kubectl apply -f prometheus.yaml
