基于Docker多阶段构建优化带共享库的C应用镜像大小

问题背景 #

我有一个依赖多个共享库的C应用，其中部分库是从GitHub下载源码后在容器中编译安装的。由于构建过程需要安装大量构建工具和依赖，最终镜像体积达到了约564MB，希望能减小镜像体积。我考虑了两种优化方案：

• 使用静态库：看似简单，但需要将部分现有共享库转换为静态库，操作复杂度较高；
• Docker多阶段构建：在builder容器中构建共享库和应用，再将产物复制到final容器中。

应用依赖的共享库列表 #

通过ldd命令查看，应用依赖的共享库如下：

ldd anomapp 
        linux-vdso.so.1 (0x00007ffcfa7fe000)
        librdkafka.so.1 => /usr/local/lib/librdkafka.so.1 (0x00007f9ad3c91000)
        libbgpstream.so.3 => /usr/local/lib/libbgpstream.so.3 (0x00007f9ad3c52000)
        libhiredis.so.1.1.0 => /usr/local/lib/libhiredis.so.1.1.0 (0x00007f9ad3c3c000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9ad3a4a000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f9ad38fb000)
        libcurl.so.4 => /lib/x86_64-linux-gnu/libcurl.so.4 (0x00007f9ad3868000)
        libzstd.so.1 => /lib/x86_64-linux-gnu/libzstd.so.1 (0x00007f9ad37bd000)
        libssl.so.1.1 => /lib/x86_64-linux-gnu/libssl.so.1.1 (0x00007f9ad372a000)
        libcrypto.so.1.1 => /lib/x86_64-linux-gnu/libcrypto.so.1.1 (0x00007f9ad3454000)
        libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f9ad3438000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9ad3432000)
        libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f9ad340f000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f9ad3ef2000)
        libparsebgp.so.2 => /usr/local/lib/libparsebgp.so.2 (0x00007f9ad33f4000)
        libwandio.so.6 => /usr/local/lib/libwandio.so.6 (0x00007f9ad33e5000)
        libnghttp2.so.14 => /lib/x86_64-linux-gnu/libnghttp2.so.14 (0x00007f9ad33bc000)
        libidn2.so.0 => /lib/x86_64-linux-gnu/libidn2.so.0 (0x00007f9ad339b000)
        librtmp.so.1 => /lib/x86_64-linux-gnu/librtmp.so.1 (0x00007f9ad337b000)
        libssh.so.4 => /lib/x86_64-linux-gnu/libssh.so.4 (0x00007f9ad330d000)
        libpsl.so.5 => /lib/x86_64-linux-gnu/libpsl.so.5 (0x00007f9ad32f8000)
        libgssapi_krb5.so.2 => /lib/x86_64-linux-gnu/libgssapi_krb5.so.2 (0x00007f9ad32ab000)
        libldap_r-2.4.so.2 => /lib/x86_64-linux-gnu/libldap_r-2.4.so.2 (0x00007f9ad3255000)
        liblber-2.4.so.2 => /lib/x86_64-linux-gnu/liblber-2.4.so.2 (0x00007f9ad3244000)
        libbrotlidec.so.1 => /lib/x86_64-linux-gnu/libbrotlidec.so.1 (0x00007f9ad3236000)
        libbz2.so.1.0 => /lib/x86_64-linux-gnu/libbz2.so.1.0 (0x00007f9ad3221000)
        libunistring.so.2 => /lib/x86_64-linux-gnu/libunistring.so.2 (0x00007f9ad309f000)
        libgnutls.so.30 => /lib/x86_64-linux-gnu/libgnutls.so.30 (0x00007f9ad2ec9000)
        libhogweed.so.5 => /lib/x86_64-linux-gnu/libhogweed.so.5 (0x00007f9ad2e92000)
        libnettle.so.7 => /lib/x86_64-linux-gnu/libnettle.so.7 (0x00007f9ad2e58000)
        libgmp.so.10 => /lib/x86_64-linux-gnu/libgmp.so.10 (0x00007f9ad2dd4000)
        libkrb5.so.3 => /lib/x86_64-linux-gnu/libkrb5.so.3 (0x00007f9ad2cf5000)
        libk5crypto.so.3 => /lib/x86_64-linux-gnu/libk5crypto.so.3 (0x00007f9ad2cc4000)
        libcom_err.so.2 => /lib/x86_64-linux-gnu/libcom_err.so.2 (0x00007f9ad2cbd000)
        libkrb5support.so.0 => /lib/x86_64-linux-gnu/libkrb5support.so.0 (0x00007f9ad2cae000)
        libresolv.so.2 => /lib/x86_64-linux-gnu/libresolv.so.2 (0x00007f9ad2c92000)
        libsasl2.so.2 => /lib/x86_64-linux-gnu/libsasl2.so.2 (0x00007f9ad2c75000)
        libgssapi.so.3 => /lib/x86_64-linux-gnu/libgssapi.so.3 (0x00007f9ad2c2e000)
        libbrotlicommon.so.1 => /lib/x86_64-linux-gnu/libbrotlicommon.so.1 (0x00007f9ad2c0b000)
        libp11-kit.so.0 => /lib/x86_64-linux-gnu/libp11-kit.so.0 (0x00007f9ad2ad5000)
        libtasn1.so.6 => /lib/x86_64-linux-gnu/libtasn1.so.6 (0x00007f9ad2abf000)
        libkeyutils.so.1 => /lib/x86_64-linux-gnu/libkeyutils.so.1 (0x00007f9ad2ab8000)
        libheimntlm.so.0 => /lib/x86_64-linux-gnu/libheimntlm.so.0 (0x00007f9ad2aaa000)
        libkrb5.so.26 => /lib/x86_64-linux-gnu/libkrb5.so.26 (0x00007f9ad2a17000)
        libasn1.so.8 => /lib/x86_64-linux-gnu/libasn1.so.8 (0x00007f9ad2971000)
        libhcrypto.so.4 => /lib/x86_64-linux-gnu/libhcrypto.so.4 (0x00007f9ad2939000)
        libroken.so.18 => /lib/x86_64-linux-gnu/libroken.so.18 (0x00007f9ad2920000)
        libffi.so.7 => /lib/x86_64-linux-gnu/libffi.so.7 (0x00007f9ad2914000)
        libwind.so.0 => /lib/x86_64-linux-gnu/libwind.so.0 (0x00007f9ad28e8000)
        libheimbase.so.1 => /lib/x86_64-linux-gnu/libheimbase.so.1 (0x00007f9ad28d6000)
        libhx509.so.5 => /lib/x86_64-linux-gnu/libhx509.so.5 (0x00007f9ad2888000)
        libsqlite3.so.0 => /lib/x86_64-linux-gnu/libsqlite3.so.0 (0x00007f9ad275f000)
        libcrypt.so.1 => /lib/x86_64-linux-gnu/libcrypt.so.1 (0x00007f9ad2724000)

多阶段构建操作及问题解决 #

我采用多阶段构建方案，将builder容器中编译好的库复制到生产容器中，复制命令如下：

# 复制前一阶段构建的库文件
COPY --from=builder /usr/local/lib/* /usr/local/lib/

最初执行后遇到了共享库找不到的问题，后来发现需要执行ldconfig命令更新系统的库缓存，添加以下代码后问题解决：

RUN ldconfig /usr/local/lib
RUN export LD_LIBRARY_PATH="/lib:/usr/lib:/usr/local/lib"
RUN ldconfig -v

内容的提问来源于stack exchange，提问作者codingfreak