docker问题集

[lqshow]

如何在docker run中运行多条指令

docker run -d  \
 --restart always \
 -p 13200:13200 \
 --volume /root/.m2:/root/.m2  \
 --env NODE_ENV=test  \
 enigma:0.0.1 \
 /bin/sh -c 'cd /data/project/service; npm run build-xfs; ./bin/start.sh'

Docker环境变量如何设置

1. 通过Dockerfile设置

FROM debian:wheezy
ENV NODE_ENV test

查看容器中的环境变量

➜  /Users/linqiong/workspace/docker/example docker run -it --rm example env

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=45804cf45f6f
TERM=xterm
NODE_ENV=test
HOME=/root

2. 通过docker run命令中的-e或--env值来设置环境变量

这里传递的环境变量值会覆盖掉Dockerfile中设置的环境变量值

docker run \
	-it \
	--rm \
	-e NODE_ENV=bb \
	-e HADOOP_HOME=/opt/hadoop/current \
	example env

查看执行结果

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=2f2a77b3dfea
TERM=xterm
NODE_ENV=bb
HADOOP_HOME=/opt/hadoop/current
HOME=/root

3.配置环境变量文件， 再通过docker run命令中的--env-file参数传入

该方法的好处是可以不将环境变量的值暴露出去

1. 创建.env配置文件

echo "NODE_ENV=production\nKAFKA_HOME=/opt/kafka/current" > .env

2. 执行docker run命令

docker run -it --rm --env-file ./.env example env

3. 查看执行结果

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=17ec8d22fad8
TERM=xterm
NODE_ENV=production
KAFKA_HOME=/opt/kafka/current
HOME=/root

同主机下容器间通信

默认情况下主机和容器是可以相互通信的
docker提供了--link 容器名:别名，运行容器启动的时候通过--link来指定要和哪个容器通信。

容器	IP
workspace	172.17.0.8
dashboard-app-runner	172.17.0.15

如果xdp-workspace-api容器需要访问dashboard-app-runner，创建workspace的容器方式如下

docker run -d \
 --name workspace \
 --link dashboard-app-runner:dashboard \
 --restart always \
 -p 3201:3201  enigma:0.0.1

workspcae hosts如下

workspace访问dashboard调用方式：http://dashboard:14200/api/v2

容器内运行spark应用

以下需要指定配置

Property Name	desc
spark.driver.bindAddress	容器host名称或者ip地址
spark.driver.host	主机名或者IP地址
spark.driver. port	驱动器监听端口号
spark.ui.port	应用程序dashboard的端口
spark.blockManager.port	块管理器监听的端口

References

• Running Spark driver program in Docker container - no connection back from executor to the driver?
• Docker image to run Spark applications
• Running Apache Spark Applications in Docker Containers
• Docker image to submit Spark applications

如何设置容器默认时区

在Dockerfile中配置

CentOS

ENV TZ=Asia/Shanghai
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

Ubuntu

RUN echo "Asia/Shanghai" > /etc/timezone && \
    dpkg-reconfigure -f noninteractive tzdata

如何在构建镜像时使用SSH

相关问题：GitLab CI/CD中使用SSH私钥

resource与Dockerfile为同级目录，id_rsa为本机的私钥

CentOs

# Add credentials on build
RUN mkdir -p /root/.ssh
Add resource/id_rsa /root/.ssh/id_rsa
RUN chmod 600 /root/.ssh/id_rsa && \
      echo 'StrictHostKeyChecking no' >> /etc/ssh/ssh_config


# Remove SSH keys
RUN rm -rf /root/.ssh/

Ubuntu

# Add credentials on build
RUN mkdir -p /root/.ssh
Add resource/id_rsa /root/.ssh/id_rsa
RUN chmod 600 /root/.ssh/id_rsa && \
      echo "StrictHostKeyChecking no\nUserKnownHostsFile /dev/null" >> /root/.ssh/config


# Remove SSH keys
RUN rm -rf /root/.ssh/

Reference

在docker容器中使用SSH密钥

docker-compose使用过程中的网络通信问题

如果docker-compose.yml没有配置networks，在运行docker-compose up时它会默认创建一个default的network，这里需要注意的是，如果默认创建的network的subnet正好是项目中用到的subnet，这里就会有问题。比如说项目中连的redis为172.18.0.105:6379，而default network如下所示

➜  /Users/linqiong/workspace/basebit/gitlab/dockerfile/centos_enigma git:(master) ✗ docker network inspect enigma_backend
[
    {
        "Name": "enigma_backend",
        "Id": "1a10dd8b06a6e639e1ba3dc1ddfba899b3868b226f840765382f4e86a7db7192",
        "Created": "2018-05-06T14:12:11.576372418Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                   "Subnet": "172.18.0.0/16",
                    "Gateway": "172.18.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {},
        "Options": {},
        "Labels": {}
    }
]

解决方案：可以手动设置一个network

docker network create --subnet=172.19.0.0/16 enigma_backend

验证码乱码

容器环境缺少字体引起

RUN yum install -y curl cabextract xorg-x11-font-utils fontconfig
RUN mkdir -p /root/fonts
COPY resource/msttcore-fonts-installer-2.6-1.noarch.rpm /root/fonts/msttcore-fonts-installer-2.6-1.noarch.rpm
RUN rpm -i /root/fonts/msttcore-fonts-installer-2.6-1.noarch.rpm

Reference

Get Microsoft's Core Fonts for the Web and Cleartype Fonts