PostgreSQL を Docker 化する
読む時間の目安: 4 分
Docker での PostgreSQL インストール
条件に合う Docker イメージが Docker Hub にはなかったと仮定して、自分で作ることにします。
新たにDockerfileを作るところから始めます。
メモ
この PostgreSQL 環境の構築は、単に開発目的で行うものです。 PostgreSQL に対する設定が、適切に安全なものに Refer to the PostgreSQL documentation to fine-tune these settings so that it is suitably secure.
# syntax=docker/dockerfile:1
FROM ubuntu:16.04
# Add the PostgreSQL PGP key to verify their Debian packages.
# It should be the same key as https://www.postgresql.org/media/keys/ACCC4CF8.asc
RUN apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys B97B0AFCAA1A47F044F244A07FCC7D46ACCC4CF8
# Add PostgreSQL's repository. It contains the most recent stable release
# of PostgreSQL.
RUN echo "deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main" > /etc/apt/sources.list.d/pgdg.list
# Install ``python-software-properties``, ``software-properties-common`` and PostgreSQL 9.3
# There are some warnings (in red) that show up during the build. You can hide
# them by prefixing each apt-get statement with DEBIAN_FRONTEND=noninteractive
RUN apt-get update && apt-get install -y python-software-properties software-properties-common postgresql-9.3 postgresql-client-9.3 postgresql-contrib-9.3
# Note: The official Debian and Ubuntu images automatically ``apt-get clean``
# after each ``apt-get``
# Run the rest of the commands as the ``postgres`` user created by the ``postgres-9.3`` package when it was ``apt-get installed``
USER postgres
# Create a PostgreSQL role named ``docker`` with ``docker`` as the password and
# then create a database `docker` owned by the ``docker`` role.
# Note: here we use ``&&\`` to run commands one after the other - the ``\``
# allows the RUN command to span multiple lines.
RUN /etc/init.d/postgresql start &&\
psql --command "CREATE USER docker WITH SUPERUSER PASSWORD 'docker';" &&\
createdb -O docker docker
# Adjust PostgreSQL configuration so that remote connections to the
# database are possible.
RUN echo "host all all 0.0.0.0/0 md5" >> /etc/postgresql/9.3/main/pg_hba.conf
# And add ``listen_addresses`` to ``/etc/postgresql/9.3/main/postgresql.conf``
RUN echo "listen_addresses='*'" >> /etc/postgresql/9.3/main/postgresql.conf
# Expose the PostgreSQL port
EXPOSE 5432
# Add VOLUMEs to allow backup of config, logs and databases
VOLUME ["/etc/postgresql", "/var/log/postgresql", "/var/lib/postgresql"]
# Set the default command to run when starting the container
CMD ["/usr/lib/postgresql/9.3/bin/postgres", "-D", "/var/lib/postgresql/9.3/main", "-c", "config_file=/etc/postgresql/9.3/main/postgresql.conf"]
Dockerfile からイメージをビルドして名前を与えます。
$ docker build -t eg_postgresql .
PostgreSQL サーバーコンテナーを（フォアグラウンドで）実行します。
$ docker run --rm -P --name pg_test eg_postgresql
PostgreSQL サーバーへの接続方法は２通りあります。 リンクコンテナー を使うか、ホスト（あるいはネットワーク）からアクセスします。
メモ
--rmは、コンテナーが正常終了したときに、コンテナーとそのイメージを削除するものです。
コンテナーリンクの利用
Containers can be linked to another container’s ports directly using
--link remote_name:local_alias in the client’s
docker run. This sets a number of environment
variables that can then be used to connect:
$ docker run --rm -t -i --link pg_test:pg eg_postgresql bash
postgres@7ef98b1b7243:/$ psql -h $PG_PORT_5432_TCP_ADDR -p $PG_PORT_5432_TCP_PORT -d docker -U docker --password
ホストシステムからの接続
Assuming you have the postgresql-client installed, you can use the
host-mapped port to test as well. You need to use docker ps
to find out what local host port the container is mapped to
first:
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5e24362f27f6 eg_postgresql:latest /usr/lib/postgresql/ About an hour ago Up About an hour 0.0.0.0:49153->5432/tcp pg_test
$ psql -h localhost -p 49153 -d docker -U docker --password
データベースの動作確認
Once you have authenticated and have a docker =#
prompt, you can create a table and populate it.
psql (9.3.1)
Type "help" for help.
$ docker=# CREATE TABLE cities (
docker(# name varchar(80),
docker(# location point
docker(# );
CREATE TABLE
$ docker=# INSERT INTO cities VALUES ('San Francisco', '(-194.0, 53.0)');
INSERT 0 1
$ docker=# select * from cities;
name | location
---------------+-----------
San Francisco | (-194,53)
(1 row)
コンテナーボリュームの利用
You can use the defined volumes to inspect the PostgreSQL log files and to backup your configuration and data:
$ docker run --rm --volumes-from pg_test -t -i busybox sh
/ # ls
bin etc lib linuxrc mnt proc run sys usr
dev home lib64 media opt root sbin tmp var
/ # ls /etc/postgresql/9.3/main/
environment pg_hba.conf postgresql.conf
pg_ctl.conf pg_ident.conf start.conf
/tmp # ls /var/log
ldconfig postgresql