Simple Builds break on Docker Hub with Gem::FilePermissionError

[captn3m0]

Using the ruby:alpine image, and a very minimal Dockerfile. Builds work locally:

[+] Building 4.7s (9/9) FINISHED                                                                                                                                                                                                                                                    
 => [internal] load build definition from Dockerfile
 => => transferring dockerfile: 37B
 => [internal] load .dockerignore
 => => transferring context: 58B
 => [internal] load metadata for docker.io/library/ruby:alpine
 => CACHED [1/4] FROM docker.io/library/ruby:alpine
 => [internal] load build context
 => => transferring context: 4.35kB
 => [2/4] WORKDIR /usr/src/app
 => [3/4] COPY . /usr/src/app
 => [4/4] RUN bundle install
 => exporting to image
 => => exporting layers
 => => writing image sha256:1b519f143b4c8f1e21ecc3a11bb911be36d27a2f44c997e6511f821467796b10

However, builds break on DockerHub:

Components: [{u'Version': u'19.03.8', u'Name': u'Engine', u'Details': {u'KernelVersion': u'4.4.0-1060-aws', u'Os': u'linux', u'BuildTime': u'2020-03-11T01:24:30.000000000+00:00', u'ApiVersion': u'1.40', u'MinAPIVersion': u'1.12', u'GitCommit': u'afacb8b7f0', u'Arch': u'amd64', u'Experimental': u'false', u'GoVersion': u'go1.12.17'}}, {u'Version': u'1.2.13', u'Name': u'containerd', u'Details': {u'GitCommit': u'7ad184331fa3e55e52b890ea95e65ba581ae3429'}}, {u'Version': u'1.0.0-rc10', u'Name': u'runc', u'Details': {u'GitCommit': u'dc9208a3303feef5b3839f4323d9beb36df0a9dd'}}, {u'Version': u'0.18.0', u'Name': u'docker-init', u'Details': {u'GitCommit': u'fec3683'}}]
Arch: amd64
BuildTime: 2020-03-11T01:24:30.000000000+00:00
ApiVersion: 1.40
Platform: {u'Name': u'Docker Engine - Community'}
Version: 19.03.8
MinAPIVersion: 1.12
GitCommit: afacb8b7f0
GoVersion: go1.12.17
#8 [4/4] RUN bundle install
#8 1.149 `/root` is not writable.
#8 1.149 Bundler will use `/tmp/bundler20210713-1-aeohbg1' as your home directory temporarily.
#8 2.029 ## Backtrace
#8 2.029
#8 2.029 ```
#8 2.029 Gem::FilePermissionError: You don't have write permissions for the /usr/local/bundle directory.
#8 2.029 /usr/local/lib/ruby/3.0.0/rubygems/installer.rb:715:in `verify_gem_home'
#8 2.029 /usr/local/lib/ruby/3.0.0/rubygems/installer.rb:887:in `pre_install_checks'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/rubygems_gem_installer.rb:59:in `pre_install_checks'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/rubygems_gem_installer.rb:12:in `install'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/source/rubygems.rb:182:in `install'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/installer/gem_installer.rb:67:in `install'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/installer/gem_installer.rb:18:in `install_from_spec'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/installer/parallel_installer.rb:186:in `do_install'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/installer/parallel_installer.rb:177:in `block in worker_pool'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/worker.rb:62:in `apply_func'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/worker.rb:57:in `block in process_queue'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/worker.rb:54:in `loop'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/worker.rb:54:in `process_queue'
#8 2.029 /usr/local/lib/ruby/3.0.0/bundler/worker.rb:88:in `block (2 levels) in create_threads'
#8 2.029 ```
#8 2.029
#8 2.029 ## Environment
#8 2.029
#8 2.029 ```
#8 2.029 Bundler 2.2.22
#8 2.029 Platforms ruby, x86_64-linux-musl
#8 2.029 Ruby 3.0.2p107 (2021-07-07 revision 0db68f023372b634603c74fca94588b457be084c) [x86_64-linux-musl]
#8 2.029 Full Path /usr/local/bin/ruby
#8 2.029 Config Dir /usr/local/etc
#8 2.029 RubyGems 3.2.22
#8 2.029 Gem Home /usr/local/bundle
#8 2.029 Gem Path /root/.local/share/gem/ruby/3.0.0:/usr/local/lib/ruby/gems/3.0.0:/usr/local/bundle
#8 2.029 User Home /root
#8 2.029 User Path /root/.local/share/gem/ruby/3.0.0
#8 2.029 Bin Dir /usr/local/bundle/bin
#8 2.029 OpenSSL
#8 2.029 Compiled OpenSSL 1.1.1k 25 Mar 2021
#8 2.029 Loaded OpenSSL 1.1.1k 25 Mar 2021
#8 2.029 Cert File /etc/ssl/cert.pem
#8 2.029 Cert Dir /etc/ssl/certs
#8 2.029 Tools
#8 2.029 Git not installed
#8 2.029 RVM not installed
#8 2.029 rbenv not installed
#8 2.029 chruby not installed
#8 2.029 ```
#8 2.029
#8 2.029 ## Bundler Build Metadata
#8 2.029
#8 2.029 ```
#8 2.029 Built At 2021-07-13
#8 2.029 Git SHA unknown
#8 2.029 Released Version false
#8 2.029 ```
#8 2.029
#8 2.029 ## Bundler settings
#8 2.029
#8 2.029 ```
#8 2.029 app_config
#8 2.029 Set via BUNDLE_APP_CONFIG: "/usr/local/bundle"
#8 2.029 silence_root_warning
#8 2.029 Set via BUNDLE_SILENCE_ROOT_WARNING: true
#8 2.029 ```
#8 2.029
#8 2.029 ## Gemfile
#8 2.029
#8 2.029 ### Gemfile
#8 2.029
#8 2.029 ```ruby
#8 2.029 # frozen_string_literal: true
#8 2.029
#8 2.029 source "https://rubygems.org"
#8 2.029
#8 2.029 gem "redis"
#8 2.029 ```
#8 2.029
#8 2.029 ### Gemfile.lock
#8 2.029
#8 2.029 ```
#8 2.029 GEM
#8 2.029 remote: https://rubygems.org/
#8 2.029 specs:
#8 2.029 redis (4.3.1)
#8 2.029
#8 2.029 PLATFORMS
#8 2.029 ruby
#8 2.029
#8 2.029 DEPENDENCIES
#8 2.029 redis
#8 2.029
#8 2.029 BUNDLED WITH
#8 2.029 2.2.23
#8 2.029

The user is root, and it has the right permissions, but it still breaks.

Not sure if this is the right place to report it, but creating here since others might be impacted as well.

[captn3m0]

Reported on the Docker Forum: https://forums.docker.com/t/builds-on-docker-hub-fail-with-ruby-alpine-image-but-succeed-elsewhere/112469

[captn3m0]

This fixes itself on running against ruby:alpine3.13 instead: https://hub.docker.com/repository/registry-1.docker.io/captn3m0/dockerhub-ruby-build-issue/builds/5cb2b525-09d6-40c6-9d4b-a2520c6bd5bd

[captn3m0]

Nevermind, this is same as #351