How to add user with dockerfile?

Question

How can I add a user with Dockerfile - the following does not work.

USER vault
WORKDIR /usr/local/bin/vault

My full Dockerfile:

FROM alpine:3.4
RUN apk update && apk add curl unzip
RUN useradd -ms /bin/bash vault

USER vault
WORKDIR /usr/local/bin/vault
ADD /vault.hcl /etc/vault/vault.hcl

RUN curl -SL https://releases.hashicorp.com/vault/0.5.0/vault_0.5.0_linux_amd64.zip > vault.zip
RUN unzip vault.zip -d /usr/local/bin && rm vault.zip

Answer 1

Use useradd instead of its interactive adduser to add user.

RUN useradd -ms /bin/bash  vault

Below command will not create user .

USER vault
WORKDIR /usr/local/bin/vault

it will use vault user

please Refer Dockerfile User Documentation

The USER instruction sets the user name or UID to use when running the image and for any RUN, CMD and ENTRYPOINT instructions that follow it in the Dockerfile.

NOTE : Ensures that bash is the default shell.

If default shell is /bin/sh you can do like:

RUN ln -sf /bin/bash /bin/sh
RUN useradd -ms /bin/bash  vault

Answer 2

To add group and to associate a new user, use code below.

FROM <base image>
RUN groupadd -g 2000 go \
&& useradd -m -u 2001 -g go go
USER go

OR

RUN addgroup -g 1001 -S appuser && adduser -u 1001 -S appuser -G appuser