The goal of this instruction is to enable users to create Docker images that contain a predefined postgres instance with existing schema and data. We will use the official docker postgres image and mostly docker's own commands.
The first step is to setup a docker container running postgres containing t# Create snapshot of dockerized postgres
The goal of this instruction is to enable users to create Docker images that contain a predefined postgres instance with existing schema and data. We will use the official docker postgres image and mostly docker's own commands.
The first step is to setup a docker container running postgres containing the schema and data that we want to include in the created snapshot:
docker run --name postgres-container -d postgresPer default the postgres container stores any schema information and data in the mounted volume directory /var/lib/postgresql/data (ref). Thus docker commit does not take along this volume data we copy them to a separate file location:
docker exec -it postgres-container cp -r /var/lib/postgresql/data postgres-dataNow that we have copied the data to a different directory than the mounted one, we can commit the container instance and back up our data:
docker commit postgres-container postgres-with-dataThe created image contains our backed up schema and data in the postgres-data image.
To start a container instance from this image we only have to tell postgres where it may find the data stored instead to use the default location. We use the PGDATA environment variable for this purpose here:
docker run —env PGDATA=postgres-data -d postgres-with-dataDocker commit does not include any data contained in volumes mounted inside the container (docker commit).