Docker，一个或多个未使用的build-args

Question

我正在尝试使用自定义环境变量构建Oracle WebLogic Docker镜像

$ docker build -t 12213-domain --build-arg ADMIN_PORT=8888 --build-arg ADMIN_PASSWORD=wls .

但是我在构建日志中得到了以下警告

[Warning] One or more build-args [ADMIN_PASSWORD ADMIN_PORT] were not consumed

下面是我正在尝试构建的镜像的Dockerfile

#Copyright (c) 2014-2017 Oracle and/or its affiliates. All rights reserved.
#
#Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
#
# ORACLE DOCKERFILES PROJECT
# --------------------------
# This Dockerfile extends the Oracle WebLogic image by creating a sample domain.
#
# Util scripts are copied into the image enabling users to plug NodeManager 
# automatically into the AdminServer running on another container.
#
# HOW TO BUILD THIS IMAGE
# -----------------------
# Put all downloaded files in the same directory as this Dockerfile
# Run: 
#      $ sudo docker build -t 12213-domain
#
# Pull base image
# ---------------
FROM oracle/weblogic:12.2.1.3-developer

# Maintainer
# ----------
MAINTAINER Monica Riccelli <monica.riccelli@oracle.com>

# WLS Configuration 
# ---------------------------
ENV ADMIN_HOST="wlsadmin" \
    NM_PORT="5556" \
    MS_PORT="8001" \
    DEBUG_PORT="8453" \
    ORACLE_HOME=/u01/oracle \
    SCRIPT_FILE=/u01/oracle/createAndStartWLSDomain.sh \
    CONFIG_JVM_ARGS="-Dweblogic.security.SSL.ignoreHostnameVerification=true"  \
    PATH=$PATH:/u01/oracle/oracle_common/common/bin:/u01/oracle/wlserver/common/bin:/u01/oracle/user_projects/domains/${DOMAIN_NAME:-base_domain}/bin:/u01/oracle

# Domain and Server environment variables
# ------------------------------------------------------------
ENV DOMAIN_NAME="${DOMAIN_NAME:-base_domain}" \
    PRE_DOMAIN_HOME=/u01/oracle/user_projects \
    ADMIN_PORT="${ADMIN_PORT:-7001}"  \
    ADMIN_USERNAME="${ADMIN_USERNAME:-weblogic}" \
    ADMIN_NAME="${ADMIN_NAME:-AdminServer}" \
    MS_NAME="${MS_NAME:-""}" \
    NM_NAME="${NM_NAME:-""}" \
    ADMIN_PASSWORD="${ADMIN_PASSWORD:-""}" \
    CLUSTER_NAME="${CLUSTER_NAME:-DockerCluster}" \
    DEBUG_FLAG=true \
    PRODUCTION_MODE=dev 

# Add files required to build this image
COPY container-scripts/* /u01/oracle/

#Create directory where domain will be written to
USER root
RUN chmod +xw /u01/oracle/*.sh && \ 
    chmod +xw /u01/oracle/*.py && \ 
    mkdir -p $PRE_DOMAIN_HOME && \ 
    chmod a+xr $PRE_DOMAIN_HOME && \
    chown -R oracle:oracle $PRE_DOMAIN_HOME

VOLUME $PRE_DOMAIN_HOME
# Expose Node Manager default port, and also default for admin and managed server 
EXPOSE $NM_PORT $ADMIN_PORT $MS_PORT $DEBUG_PORT

USER oracle
WORKDIR $ORACLE_HOME

# Define default command to start bash. 
CMD ["/u01/oracle/createAndStartWLSDomain.sh"]

我在windows上运行docker-toolbox，docker版本是

$ docker --version
Docker version 18.03.0-ce, build 0520e24302

Answer 1

参数

ARG <name>[=<default value>]

构建ARG指令定义了一个变量，用户可以在构建时通过docker build命令使用--

-arg=标志将该变量传递给构建器。如果用户指定了Dockerfile中未定义的构建参数，则构建将输出警告。

[Warning] One or more build-args [foo] were not consumed.

https://docs.docker.com/engine/reference/builder/#arg

使用ARG变量的

您可以使用ARG或ENV指令来指定RUN指令可用的变量。使用ENV指令定义的环境变量始终覆盖同名的ARG指令。考虑这个带有ENV和ARG指令的Dockerfile。

与ARG指令不同，ENV值始终保存在构建的映像中。考虑一个没有-- build -arg标志的docker构建：

Docker ARG仅在镜像构建期间可用(运行等)，而不是在镜像创建并从中启动容器之后(入口点，CMD)。你可以使用ARG值来设置ENV值来解决这个问题。

所以你需要这样做

# Assign any default value to avoid any error. do not worry your build flag will override this.

    ARG ADMIN_PORT=some_default_value 

    ENV ADMIN_PORT=${ADMIN_PORT}

https://vsupalov.com/docker-arg-env-variable-guide/

更新：

简而言之，如果您将像--build-arg SOME_ARG=some_value这样的参数传递给Docker build，并且没有在Dockerfile中声明这些参数，则将打印此警告。

我要使用ARG的Dockerfile

FROM alpine
ARG SOME_ARG="Default_Value"
RUN echo "ARGS is ${SOME_ARG}"

Build命令

docker build --no-cache --build-arg SOME_ARG=some_value -t alpine .

因此，它不会输出任何警告，因为在我的Dockerfile文件中声明了ARGS。

现在，如果尝试从Dockerfile中删除参数并构建映像

FROM alpine
RUN echo "without ARGS dockerfile"

Build命令

docker build --no-cache --build-arg SOME_ARG=some_value -t alpine .

因此，现在我们将得到一个警告，一个或多个构建参数SOME_ARG未使用，因为我们没有在Dockerfile中使用或声明SOME_ARG。

​

​

Answer 2

如果你想在Docker上运行--用Dockerfile编写；

Docker-compose.yml；

version: '3.3'
services:
  somecontb:
    container_name: somecontainer
    hostname : somecontainer
    build:
      args:
        SOME_ARG: Default_Value
    context: .
      dockerfile: DockerFile
        image : someimage
    volumes:
      - somecontainer_volume:/somefile
volumes:
    somecontainer_volume:
.
.
.

DockerFile；

FROM alpine
ARG SOME_ARG
ENV SOME_ENV=$SOME_ARG

docker命令；

docker-compose down    
docker volume rm somecontainer_volume
docker-compose build --no-cache
docker-compose up -d