Can I change the username of the node user inside the Dockerfile to "dev"? Will that break things?

[Nefcanto]

Node.js Version

v24.12.0

NPM Version

11.7.0

Operating System

Linux api 6.14.0-37-generic #37~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Nov 20 10:25:38 UTC 2 x86_64 GNU/Linux

Subsystem

Other

Description

I want to have a user inside the Docker container with UID 1000 and GID 1000.

I'm already using this Dockerfile:

https://github.com/nodejs/docker-node/blob/main/24/trixie-slim/Dockerfile

I see that the node user is created with that UID and GID.

What if I rename that use to dev? Does that break anything?

Minimal Reproduction

No response

Output

No response

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[avivkeller]

@nodejs/docker

[nschonni]

https://github.com/nodejs/docker-node/blob/main/docs/BestPractices.md#non-root-user talks about changing the UID

[Nefcanto]

@nschonni I read that part. I just want to change the name of the user. This is my core image:

FROM node:lts-trixie-slim

RUN usermod -d /home/dev -l dev node

RUN sed -i 's/^Components: main$/& contrib non-free-firmware/' /etc/apt/sources.list.d/debian.sources \
    && apt-get update -qq -y \
    && apt-get upgrade -qq -y \
    && apt-get install -y --no-install-recommends \
        git procps curl inotify-tools jq python3 make g++ unzip bc jo \
    && npm install --location=global npm npm-check \
    && cd /usr/local/bin && curl -fsSL https://getmic.ro | bash \
    && apt-get clean && rm -rf /var/lib/apt/lists/*

USER dev

WORKDIR /home/dev

It builds. No problem. But then I have this panel image that uses my core image:

FROM nefcanto/core:latest

ENV PATH="${PATH}:/core/commands/panel:/core/commands"

RUN npm install --location=global serve -y

RUN echo DefaultLimitNOFILE=65536 > /etc/systemd/system.conf
RUN echo DefaultLimitNOFILE=65536 > /etc/systemd/user.conf

RUN ulimit -n 65536

It fails when I add RUN usermod -d /home/dev -l dev node line. This is the permission error:

#6 [2/5] RUN npm install --location=global serve -y
#6 3.422 npm error code EACCES
#6 3.423 npm error syscall mkdir
#6 3.423 npm error path /usr/local/lib/node_modules/serve
#6 3.423 npm error errno -13
#6 3.425 npm error Error: EACCES: permission denied, mkdir '/usr/local/lib/node_modules/serve'
#6 3.425 npm error     at async mkdir (node:internal/fs/promises:861:10)
#6 3.425 npm error     at async /usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/reify.js:572:20
#6 3.425 npm error     at async Promise.allSettled (index 0)
#6 3.425 npm error     at async #reifyPackages (/usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/reify.js:309:11)
#6 3.425 npm error     at async Arborist.reify (/usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/reify.js:121:5)
#6 3.425 npm error     at async Install.exec (/usr/local/lib/node_modules/npm/lib/commands/install.js:150:5)
#6 3.425 npm error     at async Npm.exec (/usr/local/lib/node_modules/npm/lib/npm.js:208:9)
#6 3.425 npm error     at async module.exports (/usr/local/lib/node_modules/npm/lib/cli/entry.js:67:5) {
#6 3.425 npm error   errno: -13,
#6 3.425 npm error   code: 'EACCES',
#6 3.425 npm error   syscall: 'mkdir',
#6 3.425 npm error   path: '/usr/local/lib/node_modules/serve'
#6 3.425 npm error }
#6 3.426 npm error
#6 3.426 npm error The operation was rejected by your operating system.
#6 3.426 npm error It is likely you do not have the permissions to access this f

When I run it as node user, both images are built. But when I change the username to dev it seems that the permissions are broken. Do you have any idea why?