确保从示例中复制了所有文件。在这种情况下，需要确保已经使用以下命令添加或自定义了next.config.js：

module.exports = {
  output: 'standalone'
}

您会注意到在示例中也定义了该文件：https://github.com/vercel/next.js/blob/canary/examples/with-docker/next.config.js

答案取决于您运行的Next的版本。首先，您需要取消注解Dockerfile中将server.js（以及.next/standalone文件夹的其余部分）复制到/app的那一行。

COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./

然后，您需要在next.config.js文件中包含以下内容之一，具体取决于您正在运行的Next的版本。
如果您运行的是Next 12.1.x或 * 更早版本 *，则需要：

module.exports = {
  experimental: {
    outputStandalone: true,
  },
}

如果您运行的是12.2.x或更高版本，请使用以下命令：

module.exports = {
  output: 'standalone',
}

这将导致创建.next/standalone，并且该文件夹包含server.js，这样当COPY命令运行时，它和子文件夹将被放置到/app中。

FROM node:14-alpine AS deps

# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed.

RUN apk add --no-cache libc6-compat
WORKDIR /app
COPY package.json ./
RUN npm install --frozen-lockfile
RUN npm i next@12.0.8-canary.7

# Rebuild the source code only when needed

FROM node:14-alpine AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
RUN yarn build

# Production image, copy all the files and run next

FROM node:14-alpine AS runner
WORKDIR /app

ENV NODE_ENV production

RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001

# You only need to copy next.config.js if you are NOT using the default configuration

COPY --from=builder /app/next.config.js ./
COPY --from=builder /app/public ./public
COPY --from=builder /app/package.json ./package.json
COPY --from=builder /app/.env ./

# Automatically leverage output traces to reduce image size

# https://nextjs.org/docs/advanced-features/output-file-tracing

COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

USER nextjs

EXPOSE 3000

ENV PORT 3000

# Next.js collects completely anonymous telemetry data about general usage.

# Learn more here: https://nextjs.org/telemetry

# Uncomment the following line in case you want to disable telemetry.

# ENV NEXT_TELEMETRY_DISABLED 1

CMD ["node", "server.js"]

解决了我的问题，这是新的Dockerfile，它为我工作。

只需将package.json文件中的nextjs版本更改为latest并运行yarn install。现在docker构建工作正常。

我遇到了同样的问题，冲突是我使用的是Next 11而不是12，您可以使用this dockerfile，它可以完美地运行Next 11，或者尝试以下代码。

# Install dependencies only when needed

FROM node:14-alpine AS deps

# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed.

RUN apk add --no-cache libc6-compat
WORKDIR /app
COPY package.json yarn.lock ./
RUN yarn install --frozen-lockfile

# Rebuild the source code only when needed

FROM node:14-alpine AS builder
WORKDIR /app
COPY . .
COPY --from=deps /app/node_modules ./node_modules
RUN yarn build

# Production image, copy all the files and run next

FROM node:14-alpine AS runner
WORKDIR /app

ENV NODE_ENV production

RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001

# You only need to copy next.config.js if you are NOT using the default configuration

# COPY --from=builder /app/next.config.js ./

COPY --from=builder /app/public ./public
COPY --from=builder --chown=nextjs:nodejs /app/.next ./.next
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/package.json ./package.json

USER nextjs

EXPOSE 3000

ENV PORT 3000

# Next.js collects completely anonymous telemetry data about general usage.

# Learn more here: https://nextjs.org/telemetry

# Uncomment the following line in case you want to disable telemetry.

# ENV NEXT_TELEMETRY_DISABLED 1

CMD ["node_modules/.bin/next", "start"]

TL;DR

我的下一个例子是版本11，with-docker的例子是版本12。
我在官方的Next.js with-dockerexample中查看了Dockerfile的历史。在那里我注意到添加了这些lines to the Dockerfile，以及添加了实验性标志outputStandalone。
当我的项目是next@11时，这个标志在next@12中可用，所以在我的Dockerfile中撤消这些行解决了这个问题。
查看该文件历史记录可以给予不同的问题。