Project: EDB (App Definition and Development / Database)
File: quickstart.md

This section describes how to test a PostgreSQL cluster on your laptop/computer using CloudNativePG on a local Kubernetes cluster in or . !!! Warning The instructions contained in this section are for demonstration, testing, and practice purposes only and must not be used in production. Like any other Kubernetes application, CloudNativePG is deployed using regular manifests written in YAML. By following the instructions on this page you should be able to start a PostgreSQL cluster on your local Kubernetes installation and experiment with it. !!! Important Make sure that you have `kubectl` installed on your machine in order to connect to the Kubernetes cluster. Please follow the Kubernetes documentation on . The first part is about installing Minikube or Kind. Please spend some time reading about the systems and decide which one to proceed with. After setting up one of them, please proceed with part 2. We also provide instructions for setting up monitoring with Prometheus and Grafana for local testing/evaluation, in Minikube is a tool that makes it easy to run Kubernetes locally. Minikube runs a single-node Kubernetes cluster inside a Virtual Machine (VM) on your laptop for users looking to try out Kubernetes or develop with it day-to-day. Normally, it is used in conjunction with VirtualBox. You can find more information in the official [Kubernetes documentation on how to install Minikube](https://kubernetes.io/docs/tasks/tools/install-minikube) in your local personal environment. When you installed it, run the following command to create a minikube cluster: ```sh minikube start ``` This will create the Kubernetes cluster, and you will be ready to use it. Verify that it works with the following command: ```sh kubectl get nodes ``` You will see one node called `minikube`. If you do not want to use a virtual machine hypervisor, then Kind is a tool for running local Kubernetes clusters using Docker container "nodes" (Kind stands for "Kubernetes IN Docker" indeed). Install `kind` on your environment following the instructions in the , then create a Kubernetes cluster with: ```sh kind create cluster --name pg ``` Now that you have a Kubernetes installation up and running on your laptop, you can proceed with CloudNativePG installation. Please refer to the section and then proceed with the deployment of a PostgreSQL cluster. As with any other deployment in Kubernetes, to deploy a PostgreSQL cluster you need to apply a configuration file that defines your desired `Cluster`. The sample file defines a simple `Cluster` using the default storage class to allocate disk space: ```yaml apiVersion:

kind: Cluster metadata: name: cluster-example spec: instances: 3 storage: size: 1Gi ``` !!! Note "There's more" For more detailed information about the available options, please refer to the . In order to create the 3-node PostgreSQL cluster, you need to run the following command: ```sh kubectl apply -f cluster-example.yaml ``` You can check that the pods are being created with the `get pods` command: ```sh kubectl get pods ``` That will look for pods in the default namespace. To separate your cluster from other workloads on your Kubernetes installation, you could always create a new namespace to deploy clusters on. Alternatively, you can use labels. The operator will apply the `cnpg.io/cluster` label on all objects relevant to a particular cluster. For example: ``` sh kubectl get pods -l cnpg.io/cluster=<CLUSTER> ``` !!! Important Note that we are using `cnpg.io/cluster` as the label. In the past you may have seen or used `postgresql`. This label is being deprecated, and will be dropped in the future. Please use `cngp.io/cluster`. By default, the operator will install the latest available minor version of the latest major version of PostgreSQL when the operator was released. You can override this by setting the `imageName` key in the `spec` section of the `Cluster` definition. For example, to install PostgreSQL 13.6: ```yaml apiVersion: postgresql.cnpg.io/v1 kind: Cluster metadata: spec: imageName: ghcr.io/cloudnative-pg/postgresql:13.6 ``` !!! Important The immutable infrastructure paradigm requires that you always point to a specific version of the container image. Never use tags like `latest` or `13` in a production environment as it might lead to unpredictable scenarios in terms of update policies and version consistency in the cluster. For strict deterministic and repeatable deployments, you can add the digests to the image name, through the `<image>:<tag>@sha256:<digestValue>` format. !!! Note "There's more" There are some examples cluster configurations bundled with the operator. Please refer to the . !!! Important Installing Prometheus and Grafana is beyond the scope of this project. The instructions in this section are provided for experimentation and illustration only. In this section we show how to deploy Prometheus and Grafana for observability, and how to create a Grafana Dashboard to monitor CloudNativePG clusters, and a set of Prometheus Rules defining alert conditions. We leverage the , Helm chart, which is maintained by the . Please refer to the project website for additional documentation and background. The Kube-Prometheus-stack Helm chart installs the , including the , and a deployment. We include a configuration file for the deployment of this Helm chart that will provide useful initial settings for observability of CloudNativePG clusters. If you don't have installed yet, please follow the to install it in your

We need to add the `prometheus-community` helm chart repository, and then install the Kube Prometheus stack using the sample configuration we provide: We can accomplish this with the following commands: ``` sh helm repo add prometheus-community \ https://prometheus-community.github.io/helm-charts helm upgrade --install \ -f https://raw.githubusercontent.com/cloudnative-pg/cloudnative-pg/main/docs/src/samples/monitoring/kube-stack-config.yaml \ prometheus-community \ prometheus-community/kube-prometheus-stack ``` After completion, you will have Prometheus, Grafana and Alert Manager installed with values from the `kube-stack-config.yaml` file: From the Prometheus installation, you will have the Prometheus Operator watching for any `PodMonitor` (see ). The Grafana installation will be watching for a Grafana dashboard `ConfigMap`. !!! Seealso For further information about the above command see the documentation. You can see several Custom Resources have been created: ``` sh % kubectl get crds NAME CREATED AT alertmanagers.monitoring.coreos.com <timestamp> prometheuses.monitoring.coreos.com <timestamp> prometheusrules.monitoring.coreos.com <timestamp> ``` as well as a series of Services: ``` sh % kubectl get svc NAME TYPE PORT(S) prometheus-community-grafana ClusterIP 80/TCP prometheus-community-kube-alertmanager ClusterIP 9093/TCP prometheus-community-kube-operator ClusterIP 443/TCP prometheus-community-kube-prometheus ClusterIP 9090/TCP ``` At this point, a CloudNativePG cluster deployed with Monitoring activated would be observable via Prometheus. For example, you could deploy a simple cluster with `PodMonitor` enabled: ``` sh kubectl apply -f - <<EOF apiVersion: postgresql.cnpg.io/v1 kind: Cluster metadata: name: cluster-with-metrics spec: instances: 3 storage: size: 1Gi monitoring: enablePodMonitor: true EOF ``` To access Prometheus, port-forward the Prometheus service: ``` sh kubectl port-forward svc/prometheus-community-kube-prometheus 9090 ``` Then access the Prometheus console locally at: Assuming that the monitoring stack was successfully deployed, and you have a Cluster with `enablePodMonitor: true` you should find a series of metrics relating to CloudNativePG clusters. Again, please refer to the for more information. You can now define some alerts by creating a `prometheusRule`: ``` sh kubectl apply -f \ https://raw.githubusercontent.com/cloudnative-pg/cloudnative-pg/main/docs/src/samples/monitoring/prometheusrule.yaml ``` You should see the default alerts now: ``` sh % kubectl get prometheusrules NAME AGE cnpg-default-alerts 3m27s ``` In the Prometheus console, you can click on the Alerts menu to see the alerts we just installed. In our "plain" installation, Grafana is deployed with no predefined dashboards. You can port-forward: ``` sh kubectl port-forward svc/prometheus-community-grafana 3000:80 ``` And access Grafana locally at providing the credentials `admin` as username, `prom-operator` as password (defined in `kube-stack-config.yaml`). CloudNativePG provides a default dashboard for Grafana as part of the official . You can also download the file and manually importing it via the GUI. !!! Warning Some graphs in the previous dashboard make use of metrics that are in alpha stage by the time this was created, like `kubeletvolumestatsavailablebytes` and `kubeletvolumestatscapacitybytes` producing some graphs to show `No data`. Note that in our example setup, both Prometheus and Grafana will pick up any other CloudNativePG clusters deployed with Monitoring activated.