cc_chef fails when using 'gems' installer because Ubuntu 16.04 no longer includes Ruby 1.8

Ubuntu 16.04

# dpkg -l | grep cloud-init
ii cloud-init 0.7.7~bzr1212-0ubuntu1 all Init scripts for cloud instances
ii cloud-initramfs-copymods 0.27ubuntu1 all copy initramfs modules into root filesystem for later use
ii cloud-initramfs-dyn-netconf 0.27ubuntu1 all write a network interface file in /run for BOOTIF

Minimum Ruby version supported in Ubuntu 16.04 is Ruby 2.3.

Syslog output:

May 19 23:41:38 ubuntu [CLOUDINIT] util.py[DEBUG]: apt-update [eatmydata apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet update] took 20.50
1 seconds
May 19 23:41:38 ubuntu [CLOUDINIT] util.py[DEBUG]: Running command ['eatmydata', 'apt-get', '--option=Dpkg::Options::=--force-confold', '--option=Dpkg::options::=--force-unsafe-io', '--assume-yes', '--qui
et', 'install', 'ruby1.8', 'ruby1.8-dev', 'libopenssl-ruby1.8', 'rubygems1.8'] with allowed return codes [0] (shell=False, capture=False)
May 19 23:41:39 ubuntu [CLOUDINIT] util.py[DEBUG]: apt-install [eatmydata apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install ruby1.8 r
uby1.8-dev libopenssl-ruby1.8 rubygems1.8] took 0.295 seconds
May 19 23:41:39 ubuntu [CLOUDINIT] handlers.py[DEBUG]: finish: modules-config/config-chef: FAIL: running config-chef with frequency once-per-instance
May 19 23:41:39 ubuntu [CLOUDINIT] util.py[WARNING]: Running module chef (<module 'cloudinit.config.cc_chef' from '/usr/lib/python3/dist-packages/cloudinit/config/cc_chef.py'>) failed
May 19 23:41:39 ubuntu [CLOUDINIT] util.py[DEBUG]: Running module chef (<module 'cloudinit.config.cc_chef' from '/usr/lib/python3/dist-packages/cloudinit/config/cc_chef.py'>) failed#012Traceback (most rec
ent call last):#012 File "/usr/lib/python3/dist-packages/cloudinit/stages.py", line 739, in _run_modules#012 freq=freq)#012 File "/usr/lib/python3/dist-packages/cloudinit/cloud.py", line 70, in run#0
12 return self._runners.run(name, functor, args, freq, clear_on_fail)#012 File "/usr/lib/python3/dist-packages/cloudinit/helpers.py", line 199, in run#012 results = functor(*args)#012 File "/usr/l
ib/python3/dist-packages/cloudinit/config/cc_chef.py", line 257, in handle#012 run = install_chef(cloud, chef_cfg, log)#012 File "/usr/lib/python3/dist-packages/cloudinit/config/cc_chef.py", line 296,
 in install_chef#012 install_chef_from_gems(ruby_version, chef_version, cloud.distro)#012 File "/usr/lib/python3/dist-packages/cloudinit/config/cc_chef.py", line 330, in install_chef_from_gems#012
distro.install_packages(get_ruby_packages(ruby_version))#012 File "/usr/lib/python3/dist-packages/cloudinit/distros/debian.py", line 75, in install_packages#012 self.package_command('install', pkgs=pk
glist)#012 File "/usr/lib/python3/dist-packages/cloudinit/distros/debian.py", line 176, in package_command#012 args=(cmd,), kwargs={'env': e, 'capture': False})#012 File "/usr/lib/python3/dist-packag
es/cloudinit/util.py", line 2040, in log_time#012 ret = func(*args, **kwargs)#012 File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 1704, in subp#012 cmd=args)#012cloudinit.util.Process
ExecutionError: Unexpected error while running command.#012Command: ['eatmydata', 'apt-get', '--option=Dpkg::Options::=--force-confold', '--option=Dpkg::options::=--force-unsafe-io', '--assume-yes', '--qu
iet', 'install', 'ruby1.8', 'ruby1.8-dev', 'libopenssl-ruby1.8', 'rubygems1.8']#012Exit code: 100#012Reason: -#012Stdout: ''#012Stderr: ''

# apt-cache policy ruby
ruby:
  Installed: (none)
  Candidate: 1:2.3.0+1
  Version table:
     1:2.3.0+1 500
        500 http://us-west-2.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

# apt-cache search ^ruby
rake - ruby make-like utility
ruby - Interpreter of object-oriented scripting language Ruby (default version)
ruby-all-dev - Ruby development environment (all versions supported in Debian)
ruby-dev - Header files for compiling extension modules for Ruby (default version)
ruby-did-you-mean - smart error messages for Ruby > 2.3
ruby-minitest - Ruby test tools supporting TDD, BDD, mocking, and benchmarking
ruby-net-telnet - telnet client library
ruby-power-assert - library showing values of variables and method calls in an expression
ruby-rrd - time-series data storage and display system (Ruby interfaces)
ruby-test-unit - unit testing framework for Ruby
ruby2.3 - Interpreter of object-oriented scripting language Ruby
ruby2.3-dev - Header files for compiling extension modules for the Ruby 2.3
ruby2.3-doc - Documentation for Ruby 2.3