CODEWITHSUNDEEP
docker
Alexander Solonik
Alexander Solonik

Reputation: 10250

Understanding a simple dockerfile of postgresql

I was just reading a docker file HERE.

and basically the Dockerfile looks like follows:

FROM postgres:9.1
MAINTAINER Mike Dillon <[email protected]>

ENV POSTGIS_MAJOR 2.1
ENV POSTGIS_VERSION 2.1.7+dfsg-3~94.git954a8d0.pgdg80+1

RUN apt-get update \
      && apt-get install -y --no-install-recommends \
           postgresql-$PG_MAJOR-postgis-$POSTGIS_MAJOR=$POSTGIS_VERSION \
           postgis=$POSTGIS_VERSION \
      && rm -rf /var/lib/apt/lists/*

RUN mkdir -p /docker-entrypoint-initdb.d
COPY ./initdb-postgis.sh /docker-entrypoint-initdb.d/postgis.sh

I want to make sure i have interpreted the below two commands correctly:

RUN mkdir -p /docker-entrypoint-initdb.d
COPY ./initdb-postgis.sh /docker-entrypoint-initdb.d/postgis.sh

The RUN command is running a mkdir command , which means the current directory will have a subdirectory called:

/docker-entrypoint-initdb.d

andin the next command I.E. the COPY command the contents of the directory ./initdb-postgis.sh are being copied into /docker-entrypoint-initdb.d/postgis.sh , am i right ?

Upvotes: 1

Views: 137

Answers (1)

Javier Cortejoso
Javier Cortejoso

Reputation: 9176

RUN cmd is used to execute cmd command and will create and commit a new layer for the image your are building. So those commands are run in the context of the image that is being building. mkdir -p /docker-entrypoint-initdb.d will create a new folder docker-entrypoint-initdb.d in the root of the image. COPY ./initdb-postgis.sh /docker-entrypoint-initdb.d/postgis.sh will copy the file initdb-postgis.sh (that has to be located at the same level you have run the docker build command to the file /docker-entrypoint-initdb.d/postgis.sh inside the container.

Upvotes: 2

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