Skip to content

Latest commit

 

History

History
166 lines (126 loc) · 12.6 KB

README.md

File metadata and controls

166 lines (126 loc) · 12.6 KB
Raw

CNCF Landscape Latest Release GitHub License Documentation Stack Overflow

Welcome to the CloudNativePG project!

CloudNativePG is a comprehensive open source platform designed to seamlessly manage PostgreSQL databases within Kubernetes environments, covering the entire operational lifecycle from initial deployment to ongoing maintenance. The main component is the CloudNativePG operator.

CloudNativePG was originally built and sponsored by EDB.

Table of content

Getting Started

The best way to get started is with the "Quickstart" section in the documentation.

Scope

The goal of CloudNativePG is to increase the adoption of PostgreSQL, one of the most loved DBMS in traditional VM and bare metal environments, inside Kubernetes, thus making the database an integral part of the development process and GitOps CI/CD automated pipelines.

In scope

CloudNativePG has been designed by Postgres experts with Kubernetes administrators in mind. Put simply, it leverages Kubernetes by extending its controller and by defining, in a programmatic way, all the actions that a good DBA would normally do when managing a highly available PostgreSQL database cluster.

Since the inception, our philosophy has been to adopt a Kubernetes native approach to PostgreSQL cluster management, making incremental decisions that would answer the fundamental question: "What would a Kubernetes user expect from a Postgres operator?".

The most important decision we made is to have the status of a PostgreSQL cluster directly available in the Cluster resource, so to inspect it through the Kubernetes API. We've fully embraced the operator pattern and eventual consistency, two of the core principles upon which Kubernetes is built for managing complex applications.

As a result, the operator is responsible for managing the status of the Cluster resource, keeping it up to date with the information that each PostgreSQL instance manager regularly reports back through the API server. Changes to the cluster status might trigger, for example, actions like:

  • a PostgreSQL failover where, after an unexpected failure of a cluster's primary instance, the operator itself elects the new primary, updates the status, and directly coordinates the operation through the reconciliation loop, by relying on the instance managers

  • scaling up or down the number of read-only replicas, based on a positive or negative variation in the number of desired instances in the cluster, so that the operator creates or removes the required resources to run PostgreSQL, such as persistent volumes, persistent volume claims, pods, secrets, config maps, and then coordinates cloning and streaming replication tasks

  • updates of the endpoints of the PostgreSQL services that applications rely on to interact with the database, as Kubernetes represents the single source of truth and authority

  • updates of container images in a rolling fashion, following a change in the image name, by first updating the pods where replicas are running, and then the primary, issuing a switchover first

The latter example is based on another pillar of CloudNativePG: immutable application containers - as explained in the blog article "Why EDB Chose Immutable Application Containers".

The above list can be extended. However, the gist is that CloudNativePG exclusively relies on the Kubernetes API server and the instance manager to coordinate the complex operations that need to take place in a business continuity PostgreSQL cluster, without requiring any assistance from an intermediate management tool responsible for high availability and failover management like similar open source operators.

CloudNativePG also manages additional resources to help the Cluster resource manage PostgreSQL - currently Backup, ClusterImageCatalog, ImageCatalog, Pooler, and ScheduledBackup.

Fully embracing Kubernetes means adopting a hands-off approach during temporary failures of the Kubernetes API server. In such instances, the operator refrains from taking action, deferring decisions until the API server is operational again. Meanwhile, Postgres instances persist, maintaining operations based on the latest known state of the cluster.

Out of scope

CloudNativePG is exclusively focused on the PostgreSQL database management system maintained by the PostgreSQL Global Development Group (PGDG). We are not currently considering adding to CloudNativePG extensions or capabilities that are included in forks of the PostgreSQL database management system, unless in the form of extensible or pluggable frameworks. The operator itself can be extended via a plugin interface called CNPG-I.

CloudNativePG doesn't intend to pursue database independence (e.g. control a MariaDB cluster).

Communications

Resources

Adopters

A list of publicly known users of the CloudNativePG operator is in ADOPTERS.md. Help us grow our community and CloudNativePG by adding yourself and your organization to this list!

CloudNativePG at KubeCon

Useful links

Star History

Star History Chart

Trademarks

Postgres, PostgreSQL and the Slonik Logo are trademarks or registered trademarks of the PostgreSQL Community Association of Canada, and used with their permission.