sonic容器构建
sonic中大量的组件运行在docker容器中，用于隔离彼此的运行环境，从而解决相互之间的互斥问题。下面我们分析一下sonic中各个容器的构建过程。
Dockerfile文件的生成过程
sonic中的容器Dockerfile文件是通过jinjia2模板文件生成的，使用j2命令。
sonic在编译过程中首先会构建一个叫sonic-slave的容易，该容器用来做编译容器，后续所有的编译过程都是在该容器中进行的。
编译容器生成Dockerfile
编译容器使用slave.mk作为makefile，其中有这样一段代码将Dockerfile.j2转换成Dockerfile
# Targets for building docker images$(addprefix $(TARGET_PATH)/, $(SONIC_DOCKER_IMAGES)) : $(TARGET_PATH)/%.gz : .platform docker-start $$(addprefix $(DEBS_PATH)/,$$($$*.gz_DEPENDS)) $$(addprefix $(FILES_PATH)/,$$($$*.gz_FILES)) $$(addprefix $(PYTHON_WHEELS_PATH)/,$$($$*.gz_PYTHON_WHEELS)) $$(addsuffix -load,$$(addprefix $(TARGET_PATH)/,$$($$*.gz_LOAD_DOCKERS))) $$($$*.gz_PATH)/Dockerfile.j2 $(HEADER) # Apply series of patches if exist if [ -f $($*.gz_PATH).patch/series ]; then pushd $($*.gz_PATH) && QUILT_PATCHES=../$(notdir $($*.gz_PATH)).patch quilt push -a; popd; fi mkdir -p $($*.gz_PATH)/debs $(LOG) mkdir -p $($*.gz_PATH)/files $(LOG) mkdir -p $($*.gz_PATH)/python-wheels $(LOG) sudo mount --bind $(DEBS_PATH) $($*.gz_PATH)/debs $(LOG) sudo mount --bind $(FILES_PATH) $($*.gz_PATH)/files $(LOG) sudo mount --bind $(PYTHON_WHEELS_PATH) $($*.gz_PATH)/python-wheels $(LOG) # Export variables for j2. Use path for unique variable names, e.g. docker_orchagent_debs $(eval export $(subst -,_,$(notdir $($*.gz_PATH)))_debs=$(shell printf "$(subst $(SPACE),\n,$(call expand,$($*.gz_DEPENDS),RDEPENDS))\n" | awk '!a[$$0]++')) $(eval export $(subst -,_,$(notdir $($*.gz_PATH)))_whls=$(shell printf "$(subst $(SPACE),\n,$(call expand,$($*.gz_PYTHON_WHEELS)))\n" | awk '!a[$$0]++')) $(eval export $(subst -,_,$(notdir $($*.gz_PATH)))_dbgs=$(shell printf "$(subst $(SPACE),\n,$(call expand,$($*.gz_DBG_PACKAGES)))\n" | awk '!a[$$0]++')) j2 $($*.gz_PATH)/Dockerfile.j2 > $($*.gz_PATH)/Dockerfile #使用环境变量编译Dockfile.j2 docker build --squash --no-cache \ --build-arg http_proxy=$(HTTP_PROXY) \ --build-arg https_proxy=$(HTTPS_PROXY) \ --build-arg user=$(USER) \ --build-arg uid=$(UID) \ --build-arg guid=$(GUID) \ --build-arg docker_container_name=$($*.gz_CONTAINER_NAME) \ -t $* $($*.gz_PATH) $(LOG) docker save $* | gzip -c > $@ # Clean up if [ -f $($*.gz_PATH).patch/series ]; then pushd $($*.gz_PATH) && quilt pop -a -f; popd; fi $(FOOTER)根容器：docker-base
编译的过程首先构建一个docker-base容器。
docker-base.j2
# 根容器是debian:jessieFROM debian:jessie #set up proxy 构建apt代理，会进行deb包缓存，加速编译速度RUN echo 'Acquire::http { Proxy "http://172.17.0.2:3142"; };' >>/etc/apt/apt.conf.d/01proxyRUN echo 'Acquire::HTTP::Proxy::download.docker.com "Direct";' >>/etc/apt/apt.conf.d/01proxyRUN echo 'Acquire::HTTP::Proxy::get.docker.io "Direct";' >>/etc/apt/apt.conf.d/01proxy# Clean documentation in FROM imageRUN find /usr/share/doc -depth \( -type f -o -type l \) ! -name copyright | xargs rm || true# Clean doc directories that are empty or only contain empty directoriesRUN while [ -n "$(find /usr/share/doc -depth -type d -empty -print -exec rmdir {} +)" ]; do :; doneRUN rm -rf \ /usr/share/man/* \ /usr/share/groff/* \ /usr/share/info/* \ /usr/share/lintian/* \ /usr/share/linda/* \ /var/cache/man/* \ /usr/share/locale/*# Make apt-get non-interactiveENV DEBIAN_FRONTEND=noninteractive# Configure data sources for apt/dpkgCOPY ["dpkg_01_drop", "/etc/dpkg/dpkg.cfg.d/01_drop"]COPY ["sources.list", "/etc/apt/sources.list"]COPY ["no_install_recommend_suggest", "/etc/apt/apt.conf.d"]RUN apt-get update# Pre-install fundamental packagesRUN apt-get -y install \ rsyslog \ vim-tiny \ perl \ python \ less \ gdb \ lsof \ strace \ tcpdump \ pstack \ net-tools \ sysstat \ dstat \ iotop \ htop \ lrzsz \ linux-base \ linux.perf \ linux-tools-3.16# Pre-install troubleshooting packagesRUN apt-get -y install socatCOPY ["etc/rsyslog.conf", "/etc/rsyslog.conf"]COPY ["etc/rsyslog.d/*", "/etc/rsyslog.d/"]COPY ["root/.vimrc", "/root/.vimrc"]# Install dependencies of supervisorRUN apt-get -y install python-pkg-resources python-meld3RUN mkdir -p /etc/supervisorRUN mkdir -p /var/log/supervisorCOPY ["etc/supervisor/supervisord.conf", "/etc/supervisor/"]RUN apt-get -y purge \ exim4 \ exim4-base \ exim4-config \ exim4-daemon-light#根据环境变量进行渲染，决定拷贝哪些deb到容器中{% if docker_base_debs.strip() -%}# Copy built Debian packages{%- for deb in docker_base_debs.split(' ') %}COPY debs/{{ deb }} debs/{%- endfor %}# Install built Debian packages and implicitly install their dependencies{%- for deb in docker_base_debs.split(' ') %}RUN dpkg_apt() { [ -f $1 ] && { dpkg -i $1 || apt-get -y install -f; } || return 1; }; dpkg_apt debs/{{ deb }}{%- endfor %}{%- endif %}{% if docker_base_dbgs.strip() -%}# Install common debug-packages{%- for dbg_pkg in docker_base_dbgs.split(' ') %}RUN apt-get -y install {{ dbg_pkg }}{%- endfor %}{% else %}RUN ln /usr/bin/vim.tiny /usr/bin/vim{%- endif %}# Clean up apt# Remove /var/lib/apt/lists/*, could be obsoleted for derived images# 删除所有下载的安装包，删除所有以前下载的安装包，卸载所有没有使用的包RUN apt-get clean -y; apt-get autoclean -y; apt-get autoremove -yRUN rm -rf /var/lib/apt/lists/*RUN rm -rf /tmp/*渲染后会生成docker-base/Dockerfile文件，所以要修改容器构建Dockerfile时，不能直接修改，而是修改Dockerfile
docker-config-engine
在docker-base容器的基础上安装一些python工具以及安装一些编译生成的python库，该容器没有实际的内容，只是基础容器的功能增强。
docker-config-engine/Dockerfile.j2
# 在docker-base容器上构建FROM docker-base## Make apt-get non-interactiveENV DEBIAN_FRONTEND=noninteractiveRUN apt-get update# Dependencies for sonic-cfggenRUN apt-get install -y python-lxml python-yaml python-bitarray python-pip python-dev python-natsortRUN pip install --upgrade pipRUN pip install netaddr ipaddr jinja2 pyangbind==0.5.10COPY \python-wheels/swsssdk-2.0.1-py2-none-any.whl python-wheels/sonic_config_engine-1.0-py2-none-any.whl python-wheels/RUN pip install \python-wheels/swsssdk-2.0.1-py2-none-any.whl python-wheels/sonic_config_engine-1.0-py2-none-any.whl ## Clean upRUN apt-get remove -y python-pip python-dev; apt-get clean -y; apt-get autoclean -y; apt-get autoremove -yRUN rm -rf /debs /python-wheels功能镜像
构建好了基础镜像后，后面的镜像都在docker-config-engine或者docker-base的基础上构建，这样的例如docker-orchagent-bfn，docker-fpm-frr，docker-teamd，docker-database等。
我们以docker-orchagent-bfn为例看一下功能镜像的Dockerfile文件:docker-orchagent-bfn/Dockerfile.j2
FROM docker-config-engineARG docker_container_nameRUN [ -f /etc/rsyslog.conf ] && sed -ri "s/%syslogtag%/$docker_container_name\/%syslogtag%/;" /etc/rsyslog.conf## Make apt-get non-interactiveENV DEBIAN_FRONTEND=noninteractiveRUN apt-get updateRUN apt-get install -f -y ifupdown arping libdbus-1-3 libdaemon0 libjansson4## Install redis-tools dependencies## TODO: implicitly install dependenciesRUN apt-get -y install libjemalloc1COPY \{% for deb in docker_orchagent_debs.split(' ') -%}debs/{{ deb }}{{' '}}{%- endfor -%}debs/RUN dpkg -i \{% for deb in docker_orchagent_debs.split(' ') -%}debs/{{ deb }}{{' '}}{%- endfor %}## Clean upRUN apt-get clean -y; apt-get autoclean -y; apt-get autoremove -y## 镜像构建完毕后，删除/debs目录RUN rm -rf /debsCOPY ["files/arp_update", "/usr/bin"]COPY ["enable_counters.py", "/usr/bin"]COPY ["start.sh", "orchagent.sh", "swssconfig.sh", "/usr/bin/"]COPY ["supervisord.conf", "/etc/supervisor/conf.d/"]## Copy all Jinja2 template files into the templates folderCOPY ["*.j2", "/usr/share/sonic/templates/"]ENTRYPOINT ["/usr/bin/supervisord"]