Sources:
Assumptions:
- Centos 7 platform
- You have some way to store these artifacts and make them available for systems in your environment
Caveats:
- Compiled gems are tied to Ruby version they are compiled for
- If Sensu upgrades Ruby 2.4 -> Ruby 2.5 packages have to be rebuilt
- Compiled gems are tied to CPU architecture for which they are compiled
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Drop off yum repository definition and install Sensu
$ printf '[sensu] name=sensu baseurl=https://repositories.sensuapp.org/yum/$releasever/$basearch/ gpgcheck=0 enabled=1' | sudo tee /etc/yum.repos.d/sensu.repo && yum install -y sensu
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Install EPEL and Dev tools
$ yum install -y epel-release $ yum groupinstall -y "Development Tools" -
Add Sensu's embedded bin to our path
$ which gem /usr/bin/which: no gem in (/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin) $ export PATH=$PATH:/opt/sensu/embedded/bin $ which gem /opt/sensu/embedded/bin/gem
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Install gem-compiler
$ gem install gem-compiler
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Install the source gems into a cache directory
We're going to install sensu-plugins-aws because it's dependency on nokogiri is one of the thornier examples I can think of:
$ mkdir /tmp/gems $ gem install --no-ri --no-rdoc --install-dir /tmp/gems sensu-plugins-aws
Observing the
gem installoutput, we that nokogiri and unf_ext build native extensions. These are the gems we will compile so we can install them from our own repository.
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Use gem-compiler to rebuild gem packages including native extensions
$ cd /tmp/gems/cache $ gem compile unf_ext-0.0.7.4.gem # gem-compiler readme notes nokogiri as a specific example of gems that need the --prune flag $ gem compile nokogiri-1.8.1.gem --prune -
Note that the resulting compiled gem files have a x86_64-linux in their file name:
$ ls -1 *-x86_64-linux.gem nokogiri-1.8.1-x86_64-linux.gem unf_ext-0.0.7.4-x86_64-linux.gem
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Install compiled gem into embedded Ruby
Now we can copy these gems to another system, install them into the sensu embedded ruby.
In real life you'd want to put these in a rubygems server of your own (e.g. Geminabox, Artifactory or similar) or maybe use a tool like fpm to convert them to system packages.
# Here we've copied the compiled gems to a system with Sensu installed, but no gcc or other compile toolchain # Note that nokogiri needs libxml2 and possibly libxslt to be present on your system $ /opt/sensu/embedded/bin/gem install unf_ext-0.0.7.4-x86_64-linux.gem $ /opt/sensu/embedded/bin/gem install nokogiri-1.8.1-x86_64-linux.gem
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Install Sensu plugins as normal
With these prerequisites in place we can install sensu-plugins-aws without a compiler. You can use
sensu-installorgemcommands:$ sensu-install -p aws [SENSU-INSTALL] installing Sensu plugins ... [SENSU-INSTALL] determining if Sensu gem 'sensu-plugins-aws' is already installed ... false [SENSU-INSTALL] Sensu plugin gems to be installed: ["sensu-plugins-aws"] [SENSU-INSTALL] installing Sensu gem 'sensu-plugins-aws' Fetching: unf-0.1.4.gem (100%) Successfully installed unf-0.1.4 Fetching: domain_name-0.5.20170404.gem (100%) Successfully installed domain_name-0.5.20170404 Fetching: http-cookie-1.0.3.gem (100%) Successfully installed http-cookie-1.0.3 Fetching: mime-types-2.99.3.gem (100%) Successfully installed mime-types-2.99.3 Fetching: netrc-0.11.0.gem (100%) Successfully installed netrc-0.11.0 Fetching: rest-client-1.8.0.gem (100%) Successfully installed rest-client-1.8.0 Fetching: sensu-plugins-aws-10.0.3.gem (100%) You can use the embedded Ruby by setting EMBEDDED_RUBY=true in /etc/default/sensu Successfully installed sensu-plugins-aws-10.0.3 7 gems installed [SENSU-INSTALL] successfully installed Sensu plugins: ["sensu-plugins-aws"]
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Set up our environment and test. I believe
check-elb-health-fog.rbshould exercise the nokogiri dependency:$ export AWS_ACCESS_KEY=fatchance $ export AWS_SECRET_KEY=noway $ /opt/sensu/embedded/bin/check-elb-health-fog.rb -n foo -r us-east-1 ELBHealth WARNING: An issue occured while communicating with the AWS EC2 API: There is no ACTIVE Load Balancer named 'foo'
Seems legit! 😉