Docker中有时需要修改别人制作好的镜像，一般的方法就是通过创建镜像的容器，将容器进行修改，之后通过容器创建新的镜像。本文主要介绍Docker 将容器生成镜像的三种方法。
1、使用docker commit创建镜像（推荐）
查看容器ID docker ps -a通过容器ID创建镜像2、使用docker export和docker import创建镜像
查看容器ID docker ps -a导出容器到文件 docker export > img.tar加载保存的容器创建镜像 docker import img.tar :[TAG]**注意：**使用此方法也可以将容器进行压缩，另外这样创建的容器可能不能正常启动，我们还需要指定一下启动需要参数，例如，entrypoint、cmd和环境变量等。
3、使用tar导出容器创建镜像
进入容器 sudo docker exec -it /bin/bash生成镜像文件 tar -cvf img.tar --exclude=/proc --exclude=/sys --exclude=img.tar /将容器中生成的文件拷贝到宿主机 sudo docker cp :/img.tar .创建生成镜像 cat img.tar | sudo docker import - :[TAG]**注意：**使用此方法也可以将容器进行压缩，另外这样创建的容器可能不能正常启动，我们还需要指定一下启动需要参数，例如，entrypoint、cmd和环境变量等。
4、查看镜像的Dockerfile的方法
使用docker history查看信息通过docker history查看镜像信息来分析生成Dockerfile。但少了FROM指令信息，多出来自BASIC_IMAGE的一些指令信息。使用DockerImage2Df容器工具docker commit -m "oracle 11g" d038360bc3b8 cjavapy/oracle11g:latestdocker commit用法：docker commit 参数 容器名或容器id 镜像名。参数说明：-a：提交的镜像作者；-c：使用Dockerfile指令来创建镜像；-m：提交时的说明文字；-p：在commit时，将容器暂停。（默认选项）#!/bin/bashset -uUSAGE_TIPS="Usage: ./dfimage.sh <IMAGE>"if [ !$1 ]; echo ${USAGE_TIPS} exit 1ficase "$OSTYPE" in linux*) docker history --no-trunc --format "{{.CreatedBy}}" $1 | # extract information from layers tac | # reverse the file sed 's,^\(|3.*\)\?/bin/\(ba\)\?sh -c,RUN,' | # change /bin/(ba)?sh calls to RUN sed 's,^RUN #(nop) *,,' | # remove RUN #(nop) calls for ENV,LABEL... sed 's, *&& *, \\\n \&\& ,g' # pretty print multi command lines following Docker best practices ;; darwin*) docker history --no-trunc --format "{{.CreatedBy}}" $1 | # extract information from layers tail -r | # reverse the file sed -E 's,^(\|3.*)?/bin/(ba)?sh -c,RUN,' | # change /bin/(ba)?sh calls to RUN sed 's,^RUN #(nop) *,,' | # remove RUN #(nop) calls for ENV,LABEL... sed $'s, *&& *, \\\ \\\n \&\& ,g' # pretty print multi command lines following Docker best practices ;; *) echo "unknown OSTYPE: $OSTYPE" ;;esac将上面内容存为dfimage.sh，使用方法如下，
dfimage hanxiao/mynginx:4.1# 命令aliasecho "alias image2df='docker run -v /var/run/docker.sock:/var/run/docker.sock --rm cucker/image2df'" >> ~/.bashrc. ~/.bashrc# 使用方法image2df <IMAGE项目地址**：**https://github.com/cucker0/dockerimage2df
$ echo "alias image2df='docker run -v /var/run/docker.sock:/var/run/docker.sock --rm cucker/image2df'" >> ~/.bashrc$ . ~/.bashrc$ docker pull mysql$ image2df mysql========== Dockerfile ==========FROM mysql:latestRUN groupadd -r mysql && useradd -r -g mysql mysqlRUN apt-get update && apt-get install -y --no-install-recommends gnupg dirmngr && rm -rf /var/lib/apt/lists/*ENV GOSU_VERSION=1.12RUN set -eux; \ savedAptMark="$(apt-mark showmanual)"; \ apt-get update; \ apt-get install -y --no-install-recommends ca-certificates wget; \ rm -rf /var/lib/apt/lists/*; \ dpkgArch="$(dpkg --print-architecture | awk -F- '{ print $NF }')"; \ wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch"; \ wget -O /usr/local/bin/gosu.asc "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch.asc"; \ export GNUPGHOME="$(mktemp -d)"; \ gpg --batch --keyserver hkps://keys.openpgp.org --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4; \ gpg --batch --verify /usr/local/bin/gosu.asc /usr/local/bin/gosu; \ gpgconf --kill all; \ rm -rf "$GNUPGHOME" /usr/local/bin/gosu.asc; \ apt-mark auto '.*' > /dev/null; \ [ -z "$savedAptMark" ] || apt-mark manual $savedAptMark > /dev/null; \ apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \ chmod +x /usr/local/bin/gosu; \ gosu --version; \ gosu nobody trueRUN mkdir /docker-entrypoint-initdb.dRUN apt-get update && apt-get install -y --no-install-recommends \ pwgen \ openssl \ perl \ xz-utils \ && rm -rf /var/lib/apt/lists/*RUN set -ex; \ key='A4A9406876FCBD3C456770C88C718D3B5072E1F5'; \ export GNUPGHOME="$(mktemp -d)"; \ gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \ gpg --batch --export "$key" > /etc/apt/trusted.gpg.d/mysql.gpg; \ gpgconf --kill all; \ rm -rf "$GNUPGHOME"; \ apt-key list > /dev/nullENV MYSQL_MAJOR=8.0ENV MYSQL_VERSION=8.0.24-1debian10RUN echo 'deb http://repo.mysql.com/apt/debian/ buster mysql-8.0' > /etc/apt/sources.list.d/mysql.listRUN { \ echo mysql-community-server mysql-community-server/data-dir select ''; \ echo mysql-community-server mysql-community-server/root-pass password ''; \ echo mysql-community-server mysql-community-server/re-root-pass password ''; \ echo mysql-community-server mysql-community-server/remove-test-db select false; \ } | debconf-set-selections \ && apt-get update \ && apt-get install -y \ mysql-community-client="${MYSQL_VERSION}" \ mysql-community-server-core="${MYSQL_VERSION}" \ && rm -rf /var/lib/apt/lists/* \ && rm -rf /var/lib/mysql && mkdir -p /var/lib/mysql /var/run/mysqld \ && chown -R mysql:mysql /var/lib/mysql /var/run/mysqld \ && chmod 1777 /var/run/mysqld /var/lib/mysqlVOLUME [/var/lib/mysql]COPY dir:2e040acc386ebd23b8571951a51e6cb93647df091bc26159b8c757ef82b3fcda in /etc/mysql/COPY file:345a22fe55d3e6783a17075612415413487e7dba27fbf1000a67c7870364b739 in /usr/local/bin/RUN ln -s usr/local/bin/docker-entrypoint.sh /entrypoint.sh # backwards compatENTRYPOINT ["docker-entrypoint.sh"]EXPOSE 3306 33060CMD ["mysqld"]