容器化開發環境 - 應用和數據庫隔離

上一篇容器化開發環境 - 數據庫鏈接和遷移分享了關於如何給容器中的應用建立數據庫鏈接，接下來將分享一下如何將數據庫從應用容器中分離出來。

爲何要進行分離？當應用和數據庫在同一個容器中運行時，也就意味着，應用和數據庫的生命週期捆綁在了一塊兒，應用和數據庫的運行就會出現相互干擾現象，應用的異常將有可能致使容器的中止，同時也將致使數據庫的關閉。更主要的緣由是，不少時候須要多個容器中的應用鏈接一個數據庫，爲了保證容器之間的運行相互獨立，相互不影響，就有必要將數據庫隔離在獨立的容器中運行，讓數據庫和容器獨處二人世界，同時保證數據庫的生命週期不在受其它應用影響。

Setup Codebase

• clone hello-dockerie repo

  $ git clone https://github.com/aikin/hello-dockerize.git

Separate MySQL Dockerfile

• 在dockerize目錄下建立mysql/Dockerfle

• 修改mysql/Dockerfile，配置安裝MySQL腳本：

  FROM ubuntu:14.04
  
  RUN apt-get update
  
  # === Install Mysql ===
  
  RUN groupadd -r mysql && useradd -r -g mysql mysql
  
  RUN mkdir /docker-entrypoint-initdb.d
  
  ENV MYSQL_MAJOR 5.7
  ENV MYSQL_VERSION 5.7.11-1ubuntu14.04
  
  # gpg: key 5072E1F5: public key "MySQL Release Engineering <mysql-build@oss.oracle.com>" imported
  RUN apt-key adv --keyserver ha.pool.sks-keyservers.net --recv-keys A4A9406876FCBD3C456770C88C718D3B5072E1F5
  
  RUN echo "deb http://repo.mysql.com/apt/ubuntu/ trusty mysql-${MYSQL_MAJOR}" > /etc/apt/sources.list.d/mysql.list
  
  # the "/var/lib/mysql" stuff here is because the mysql-server postinst doesn't have an explicit way to disable the mysql_install_db codepath besides having a database already "configured" (ie, stuff in /var/lib/mysql/mysql)
  # also, we set debconf keys to make APT a little quieter
  RUN { \
  echo mysql-community-server mysql-community-server/data-dir select ''; \
  echo mysql-community-server mysql-community-server/root-pass password ''; \
  echo mysql-community-server mysql-community-server/re-root-pass password ''; \
  echo mysql-community-server mysql-community-server/remove-test-db select false; \
      } | debconf-set-selections
  
  RUN apt-get update && apt-get install -y mysql-server="${MYSQL_VERSION}"
  RUN rm -rf /var/lib/apt/lists/*
  RUN rm -rf /var/lib/mysql && mkdir -p /var/lib/mysql
  
  # comment out a few problematic configuration values
  # don't reverse lookup hostnames, they are usually another container
  RUN sed -Ei 's/^(bind-address|log)/#&/' /etc/mysql/my.cnf \
      && echo 'skip-host-cache\nskip-name-resolve' | awk '{ print } $1 == "[mysqld]" && c == 0 { c = 1; system("cat") }' /etc/mysql/my.cnf > /tmp/my.cnf \
      && mv /tmp/my.cnf /etc/mysql/my.cnf
  
  VOLUME /var/lib/mysql
  
  COPY docker-entrypoint.sh /usr/local/bin/
  RUN chmod +x /usr/local/bin/docker-entrypoint.sh
  RUN ln -s usr/local/bin/docker-entrypoint.sh /entrypoint.sh # backwards compat
  ENTRYPOINT ["docker-entrypoint.sh"]
  
  EXPOSE 3306
  CMD ["mysqld"]

• 修改dockerize/Dockerfile，移除安裝MySQL的配置：

  FROM ubuntu:14.04
  
  RUN apt-get update
  
  
  ENV VERSION 8
  ENV UPDATE 66
  ENV BUILD 17
  
  ENV JAVA_HOME /usr/lib/jvm/java-${VERSION}-oracle
  ENV JRE_HOME ${JAVA_HOME}/jre
  
  
  RUN apt-get install ca-certificates curl \
  gcc libc6-dev libssl-dev make \
  -y --no-install-recommends
  
  RUN    curl --silent --location --retry 3 --cacert /etc/ssl/certs/GeoTrust_Global_CA.pem \
      --header "Cookie: oraclelicense=accept-securebackup-cookie;" \
      http://download.oracle.com/otn-pub/java/jdk/"${VERSION}"u"${UPDATE}"-b"${BUILD}"/server-jre-"${VERSION}"u"${UPDATE}"-linux-x64.tar.gz \
      | tar xz -C /tmp
  
  RUN    mkdir -p /usr/lib/jvm && mv /tmp/jdk1.${VERSION}.0_${UPDATE} "${JAVA_HOME}"
  
  RUN apt-get install -y openssl
  
  RUN apt-get remove --purge --auto-remove -y \
  gcc \
  libc6-dev \
  libssl-dev \
  make
  
  RUN    apt-get autoclean && apt-get --purge -y autoremove
  
  RUN    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
  
  RUN update-alternatives --install "/usr/bin/java" "java" "${JRE_HOME}/bin/java" 1 && \
      update-alternatives --install "/usr/bin/javac" "javac" "${JAVA_HOME}/bin/javac" 1 && \
      update-alternatives --set java "${JRE_HOME}/bin/java" && \
      update-alternatives --set javac "${JAVA_HOME}/bin/javac"
  
  WORKDIR /hello-dockerize
  
  EXPOSE 8080
  EXPOSE 5005
  CMD ["bash"]

• 將dockerize/docker-entrypoint.sh移動到dockerize/mysql目錄下

Startup

• 修改docker-compose.yml:

  web:
    build: ./dockerize
    environment:
  - LANG=C.UTF-8
  - TERM=xterm
  - DEBUG=true
    links:
    - mysql:mysql
    ports:
  - "8080:8080"
  - "5005:5005"
    volumes:
  - .:/hello-dockerize
  
  mysql:
    build: ./dockerize/mysql
    env_file: ./dockerize/dev.env
    ports:
  - "3306:3306"
    volumes:
  - /var/lib/mysql:/var/lib/mysql

• 啓動容器：

  $ docker-compose up

• 查看容器

  $ docker-compse ps
  
  ######
  Name                       Command             State                       Ports
  ---------------------------------------------------------------------------------------------------------------
  hellodockerize_mysql_1     docker-entrypoint.sh mysqld   Up      0.0.0.0:3306->3306/tcp
  hellodockerize_web_run_1   bash                          Up      0.0.0.0:5005->5005/tcp, 0.0.0.0:8080->8080/tcp
  ######

• 執行 migrate 命令:

  root@6485a7a48988:/hello-dockerize# ./gradlew flywayClean flywayInit flywayMigrate

Check Migrate Result On Intellij IDEA

• 查看 User 表

原文連接