2015/04/07

Open Source Puppet Agent Installation / Local Yum Repository for RHEL and derivatives

I've been playing for a while with Open Source Puppet and faced few challenges during its deployment. Among these challenges, there's the installation of the puppet Open Source agent on some RHEL Systems. In fact, The process to install the RHEL Puppet Open Source agent isn’t as straightforward as on CentOS and other community forks because RHEL repositories are divided into many channels and to install Puppet on it, one of this channel (the “optional channel") needs to be enabled (more details here). Meaning that both an Internet Connectivity and a valid RHN subscription are needed to complete Puppet Open Source Agent Installation on RHEL System.
Anyway, the main idea I've to workaround this small challenge is to create a small Internal http-based repository which contains all the required Package for Open Source Puppet Agent (and facter) Installation. That repository will then be used for my RHEL/CentOS node that aren't connected to Internet for Puppet Open Agent Installation.
To achieve that, the very first thing is to download Open Source Puppet Agent RPM, Facter RPM and all their dependencies in the same directory. For that, repotrack is probably one of the best tool. Indeed, this tool helps to download a package and all its dependencies recursively in the same directory. 
Repotrack is using /etc/yum.conf as default Configuration file, meaning that it'll be downloading packages based on the current repository settings. That's why I'm using a CentOS System (instead of RHEL) to create that local repository (CentOS only needs its main repo & PuppetLabs repos to be able to solve all the dependency related to Puppet/Facter).
Although in this post I'm using a CentOS 7 Distribution to download puppet/facter agent RPMS for EL7, the same process applies to lower RHEL/CentOS version (<=6), the only difference being that RHEL7 is only 64-bit, and due to that,no 32 bits repository is needed.
Enough talk, let's move forward with the following steps to complete that Local Repository configuration for CentOS7/RHEL7. 

1. Overview of the environment for this Post

This is just a short description of the System that'll be configured in this post,


System Name
OS
Description
my_repo
CentOS 7
Http-based repository (Connected to Internet)
puppetmaster
CentOS 7
Puppet Server (Connected to Internet)
my_rhel_1
RHEL 7
Puppet Client ( No Internet Connectivity)

2. On the CentOS7 Repository System, add the PuppetLabs Repository




3. Install Apache on this CentOS7 System and configure it accordingly (to make RPMS available using http)


I used my Puppet Master (and foreman) to complete this step, but a simple "yum install httpd" and httpd configuration will also be enough. The following is just for those who are interested in such Puppet configuration. If using a classic yum installation and normal httpd configuration, then you can move forward to Step 3.


On the Puppet Master Server, I'm installing Apache module





Under one of the Module Path, the module directory and the manifest folder are created.



I'm then editing a webconf manifest file to configure the Apache Module (with vhost).



The init.pp for this small module is then created to include the defined webconf




As said above, I'm using Foreman to classify my Puppet Nodes, so all these classes have then been imported under foreman (configure --> Puppet Classes --> Import from...) and the server hosting this web repository (my_repo) have been then edited to include stivrepo Module.

4. Download the CentOS7 puppet/facter Packages with all their dependencies

As discussed above, the tool used for downloading the Packages and their dependencies here is repotrack, it's part of yum-utils Packages (So, if not done, Install yum-utils). Also, if 32 bits OS will use that repository (again, RHEL7 is 64 bits only, so this comment is mostly for version below  7), then create both i686 and x86_64 under the Packages directory and use the option --arch (repotrack --arch=i686of repotrack to specify the architecture you're downloading Packages for.



5. Create and configure the repository


To create the repo, I'm using the classic createrepo with the appropriate option. It is  a program that creates a repomd (xml-based rpm metadata) repository from a set of rpms. If it isn't already installed, then install the Package.



Create the repository Metadata

Check our new repository data folder and files have been created,



It is important to note that RHEL and CentOS have a different way to interpret the releasever value on yum client configuration. In fact, CentOS interprets the realeasever variable as "OS Major Version (like 7,6,5...)" while RHEL interprets it as "OS Major Version + OS Type (7Server, 6Server, 5Server)". To make sure that our repo will be reachable from both Distribution, we'll add a Symbolic Link to the main folder.
Yum variables can be checked with the following command : "python -c 'import yum, pprint; yb = yum.YumBase(); pprint.pprint(yb.conf.yumvar, width=1)' "



At this stage, our repo is available and reachable using http URL http://stivrepo.stivameroon.net/puppet_os_agent/7/x86_64 (or http://stivrepo.stivameroon.net/puppet_os_agent/7Server/x86_64 for RHEL Server) , so the remaining is to make it available on the target System (the one without Internet Connectivity...)

6. Create a repository release RPM (optional):

The aim of this repository release RPM is just to make easy the configuration of yum on the target Systems. Indeed, we'll just have to run a normal rpm Installation to complete their yum configuration. The step is optional because one can still choose to complete manually that configuration.
To create this repository release RPM , I followed this excellent tutorial. Below is just the output of the whole process




The final thing to do is make this rpm available in the right place



7. Configure Target Systems to use the new repository:

There are 02 ways to configure the target system to use this local repository for Puppet/Facter Installation. 

The first one is automatic and apply only if step 5 of this post wasn't skipped. It consists of just installing the repository release RPM we've created.



The second one is manual and consists of adding the following file under /etc/yum.repos.d of the target System.



8. Install Puppet and Facter on the Target System:

Now, we can easily install Open Source Puppet Agent and facter by simply running the following:




Just a final note, though all the dependencies for Puppet/Facter are well resolved with this method, it might happen that there's some installed packages on the target System which depend on a package that is being upgraded for Puppet/Facter.  For such case, we might have errors similar to the one below: 




In such case, the way to workaround is simply by repotrack the package that need upgrade (libselinux-python for this example) in the right directory and update the repository using createrepo as seen below:




References:
https://www.digitalocean.com/community/tutorials/how-to-set-up-and-use-yum-repositories-on-a-centos-6-vps
http://sbr600blog.blogspot.com/2012/03/how-to-create-repository-release-rpm.html

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