用Dockerfile構(gòu)建鏡像后，npm總是無法安裝

Dockerfile文件：

#制定node鏡像的版本
FROM node:8.9-alpine

#聲明作者
MAINTAINER test

#移動當(dāng)前目錄下面的文件到app目錄下
ADD . /app/

#進(jìn)入到app目錄下面，類似cd
WORKDIR /app

#安裝依賴
RUN npm install

#對外暴露的端口
EXPOSE 3000

#程序啟動腳本
CMD ["npm", "start"]

執(zhí)行鏡像構(gòu)建 docker build -t docker_demo . 命令后：

[root@cd56723212387 testnodejs]# docker build -t docker_demo .
Sending build context to Docker daemon 17.92 kB
Step 1/7 : FROM node:8.9-alpine
Trying to pull repository docker.io/library/node ... 
8.9-alpine: Pulling from docker.io/library/node
605ce1bd3f31: Pull complete 
79b85b1676b5: Pull complete 
20865485d0c2: Pull complete 
Digest: sha256:6bb963d58da845cf66a22bc5a48bb8c686f91d30240f0798feb0d61a2832fc46
Status: Downloaded newer image for docker.io/node:8.9-alpine
 ---> 406f227b21f5
Step 2/7 : MAINTAINER test
 ---> Running in 641a6df02500
 ---> c957a05f33c1
Removing intermediate container 641a6df02500
Step 3/7 : ADD . /app/
 ---> ba5d7c9c701d
Removing intermediate container 52c5456d5f6d
Step 4/7 : WORKDIR /app
 ---> 7fc86e6854d1
Removing intermediate container c2a6af1b18fd
Step 5/7 : RUN npm install
 ---> Running in c715c3318df3

**npm ERR! code EAI_AGAIN
npm ERR! errno EAI_AGAIN
npm ERR! request to https://registry.npmjs.org/express failed, reason: getaddrinfo EAI_AGAIN registry.npmjs.org:443
npm ERR! A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2018-08-07T01_25_32_257Z-debug.log
The command '/bin/sh -c npm install' returned a non-zero code: 1**
[root@cd56723212387 testnodejs]# 

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