这看起来与 ERROR: CMake is required to build Rugged 类似，但我刚刚尝试了一次引导（bootstrap），结果发现如果不执行以下操作就会失败：
before_code:
- exec:
cd: $home
cmd:
- apt update
- apt -y install cmake
错误信息如下：
I, [2020-06-22T17:13:16.381492 #1] INFO -- : > cd /var/www/discourse && su discourse -c 'bundle exec rake db:migrate'
ERROR: Error installing rugged:
ERROR: Failed to build gem native extension.
current directory: /var/www/discourse/plugins/discourse-code-review/gems/2.6.5/gems/rugged-0.28.4.1/ext/rugged
/usr/local/bin/ruby -I /usr/local/lib/ruby/site_ruby/2.6.0 -r ./siteconf20200622-21455-f9skgp.rb extconf.rb
checking for gmake... no
checking for make... yes
checking for cmake... no
ERROR: CMake is required to build Rugged.
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/usr/local/bin/$(RUBY_BASE_NAME)
--with-sha1dc
--without-sha1dc
--use-system-libraries
To see why this extension failed to compile, please check the mkmf.log which can be found here:
/var/www/discourse/plugins/discourse-code-review/gems/2.6.5/extensions/x86_64-linux/2.6.0-static/rugged-0.28.4.1/mkmf.lo
g
extconf failed, exit code 1
但在另一台系统上，我无需此步骤就能成功添加该插件。两台系统都使用了相当标准的 web_only.yml 配置（出问题的系统部署在 Kubernetes 上，正常工作的系统使用 Traefik 作为反向代理，但我不明白这如何会影响引导过程是否运行）。
我留下这段信息，以防我的变通方法能帮助其他人，或者让了解情况的人意识到需要修改某些地方。