PostgreSQL
Contents
Postgres
https://en.wikipedia.org/wiki/PostgreSQL
PostgreSQL, often simply Postgres, is an object-relational database management system (ORDBMS) with an emphasis on extensibility and standards compliance.
Install Docker CE on Ubuntu
Docker is a technology that allows us to run containers. A container is a self-contained environment. A container can contain aspecific operating system, software packages, and configuration.
We are going to install the Docker community edition (AKA Docker CE).
https://store.docker.com/search?type=edition&offering=community
https://docs.docker.com/install/linux/docker-ce/ubuntu/
Please note that you will be required to create an account. After installing Docker, you might have to restart your computer.
Postgres docker installation
After installing Docker, you are going to need to download the Docker image for Postgres 9.5. You can do this using the following command:
sudo docker pull postgres:9.5
You can then use the following command to see the list of all the Docker images installed on your computer:
sudo docker images
Setting environment variables: In Linux and MacIn Mac and Linux we can use the following commands in Bash to create environment variables:
export DATABASE_USER=postgres
export DATABASE_PASSWORD=secret
export DATABASE_HOST=localhost
export DATABASE_PORT=5432
export DATABASE_DB=demo
The Postgres 9.5 image should be displayed in the list. At this point, we need to run a Docker container. Each container is arunning instance of an image. We can have multiple containers running of a given image, but this time we will only run onecontainer because we don't need two instances of Postgres. We can create a Docker container with the Postgres image using thefollowing command:
sudo docker run --name POSTGRES_USER -p "$DATABASE_PORT":"$DATABASE_PORT" -e POSTGRES_PASSWORD="$DATABASE_PASSWORD" -e POSTGRES_USER="$DATABASE_USER" -e POSTGRES_DB="$DATABASE_DB" -d postgres:9.5
Docker basics
We have already learned how to download Docker images using the «docker pull» command and how to create a container using the «docker run» command. We will now learn about other basic Docker commands. We can use the «docker ps» command to see all the containers in our machine:
sudo docker ps -a
We should be able to see the Postgres container running.
Each container and image has an associated ID that looks like the following:
c6f7dfc1a4c8
We can use the following command to stop a running Docker container:
sudo docker stop INSERT_CONTAINER_ID_HERE sudo docker stop c6f7dfc1a4c8
Similarly, we can run a Docker container using the start command:
sudo docker start c6f7dfc1a4c8
Please note that the run command is used to create a new Docker container while the start command is used to run an existingDocker container given its ID.
We can use the following command to remove a Docker container:
sudo docker rm c6f7dfc1a4c8
Please note that before you can remove a Docker container, you must stop it. The following command can be used to remove aDocker image:
sudo docker rmi INSERT_IMAGE_ID_HERE
Please note that before you can remove a Docker image, you must stop and remove all its associated containers.
