# Clear Linux* OS `postgres` container image

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## What is this image?

`clearlinux/postgres` is a Docker image with `postgres` running on top of the
[official clearlinux base image](https://hub.docker.com/_/clearlinux). 

<!-- application introduction -->
> [PostgreSQL](https://www.postgresql.org/) is a powerful, open source object-relational 
> database system with over 30 years of active development that has earned it a strong 
> reputation for reliability, feature robustness, and performance. 

For other Clear Linux* OS
based container images, see: https://hub.docker.com/u/clearlinux

## Why use a clearlinux based image?

<!-- CL introduction -->
> [Clear Linux* OS](https://clearlinux.org/) is an open source, rolling release
> Linux distribution optimized for performance and security, from the Cloud to
> the Edge, designed for customization, and manageability.

Clear Linux* OS based container images use:
* Optimized libraries that are compiled with latest compiler versions and
  flags.
* Software packages that follow upstream source closely and update frequently.
* An aggressive security model and best practices for CVE patching.
* A multi-staged build approach to keep a reduced container image size.
* The same container syntax as the official images to make getting started
  easy. 

To learn more about Clear Linux* OS, visit: https://clearlinux.org.

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## Deployment:

### Deploy with Docker
The easiest way to get started with this image is by simply pulling it from
Docker Hub. 

*Note: This container uses the same syntax as the [official postgres image](https://hub.docker.com/_/postgres).


1. Pull the image from Docker Hub: 
    ```
    docker pull clearlinux/postgres
    ```

2. Start a container using the examples below:

    ```
    docker run -p 5432:5432 -e POSTGRES_PASSWORD=secret -d clearlinux/postgres
    ```

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### Deploy with Kubernetes

This image can also be deployed on a Kubernetes cluster, such as [minikube](https://kubernetes.io/docs/setup/learning-environment/minikube/).The following example YAML files are provided in the repository as reference for Kubernetes deployment:

- [`postgres-deployment.yaml`](https://github.com/clearlinux/dockerfiles/blob/master/postgres/postgres-deployment.yaml): example using default configuration with secret to create a basic postgres service.
- [`postgres-deployment-conf.yaml`](https://github.com/clearlinux/dockerfiles/blob/master/postgres/postgres-deployment-conf.yaml): example using your own custom configuration with secret to create  postgres service.



Steps to deploy Postgres on a Kubernetes cluster:

1. Create secret for postgres service.

   ```
   kubectl create secret generic postgres-config \
   --from-literal=POSTGRES_DB=<your-postgres-db> \
   --from-literal=POSTGRES_PASSWORD=<your-postgres-pwd> \
   --from-literal=POSTGRES_USER=<your-postgres-user>
   ```

2. If you want to deploy `postgres-deployment.yaml` 

   ```
   kubectl create -f postgres-deployment.yaml
   ```

   Or if you want to deploy `postgres-deployment-conf.yaml` 

   ```
   kubectl create -f postgres-deployment-conf.yaml
   ```

3. Install PostgreSQL bundle and connect to the service, where 30001 is the port number defined in your service.

   ```
   swupd bundle-add postgresql
   psql -h<nodeIP> -U<your-postgres-user> --password -p30001 <your-postgres-db>
   ```

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## Build and modify:

The Dockerfiles for all Clear Linux* OS based container images are available at
https://github.com/clearlinux/dockerfiles. These can be used to build and
modify the container images.

1. Clone the clearlinux/dockerfiles repository.
    ```
    git clone https://github.com/clearlinux/dockerfiles.git
    ```

2. Change to the directory of the application:
    ```
    cd postgres/
    ```

3. Build the container image:
    ```
    docker build -t clearlinux/postgres .
    ```

   Refer to the Docker documentation for [default build arguments](https://docs.docker.com/engine/reference/builder/#arg).
   Additionally:
   
   - `swupd_args` - specifies arguments to pass to the Clear Linux* OS software
     manager. See the [swupd man pages](https://github.com/clearlinux/swupd-client/blob/master/docs/swupd.1.rst#options)
     for more information.

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## Licenses

All licenses for the Clear Linux* Project and distributed software can be found
at https://clearlinux.org/terms-and-policies