Quickstart
This section describes how to test a PostgreSQL cluster on your laptop/computer using CloudNativePG on a local Kubernetes cluster in Kind or Minikube.
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 how to install kubectl
.
Part 1 - Setup the local Kubernetes playground
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.
Minikube
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 in your local personal environment. When you installed it, run the following command to create a minikube cluster:
minikube start
This will create the Kubernetes cluster, and you will be ready to use it. Verify that it works with the following command:
kubectl get nodes
You will see one node called minikube
.
Kind
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 Quickstart,
then create a Kubernetes cluster with:
kind create cluster --name pg
Part 2 - Install CloudNativePG
Now that you have a Kubernetes installation up and running on your laptop, you can proceed with CloudNativePG installation.
Please refer to the "Installation" section and then proceed with the deployment of a PostgreSQL cluster.
Part 3 - Deploy 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 cluster-example.yaml
sample file
defines a simple Cluster
using the default storage class to allocate
disk space:
# Example of PostgreSQL cluster
apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
name: cluster-example
spec:
instances: 3
# Example of rolling update strategy:
# - unsupervised: automated update of the primary once all
# replicas have been upgraded (default)
# - supervised: requires manual supervision to perform
# the switchover of the primary
primaryUpdateStrategy: unsupervised
# Require 1Gi of space
storage:
size: 1Gi
There's more
For more detailed information about the available options, please refer to the "API Reference" section.
In order to create the 3-node PostgreSQL cluster, you need to run the following command:
kubectl apply -f cluster-example.yaml
You can check that the pods are being created with the get pods
command:
kubectl get pods
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:
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.
There's more
There are some examples cluster configurations bundled with the operator. Please refer to the "Examples" section.