Virtualization Setup for RH CSA study

While my company has wonderful resources to allow employees to study for our certifications, they are time limited to prevent waste. I find I’ve often kicked off the lab, only to get distracted with a reql-world-interrupt, and come back to find the lab has timed out. I like working on my own systems, and having my own servers to work on. As such, I’m setting up a complementary system to the corporate one for my own study.
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Matching Create and Teardown in an Ansible Role

Nothing lasts forever. Except some developer setups that no-one seems to know who owns, and no one is willing to tear down. I’ve tried to build the code to clean up after myself into my provisioning systems. One pattern I’ve noticed is that the same data is required for building and for cleaning up a cluster. When I built Ossipee, each task had both a create and a teardown stage. I want the same from Ansible. Here is how I’ve made it work thus far.

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Deploying an image on OpenStack that is bigger than the available flavors.

Today I tried to use our local OpenStack instance to deploy CloudForms Management Engine (CFME). Our OpenStack deployment has a set of flavors that all are defined with 20 GB Disks. The CFME image is larger than this, and will not deploy on the set of flavors. Here is how I worked around it.
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Freeing up a Volume from a Nova server that errored

Trial and error. Its a key part of getting work done in my field, and I make my share of errors. Today, I tried to create a virtual machine in Nova using a bad glance image that I had converted to a bootable volume:

The error message was:

 {u'message': u'Build of instance d64fdd07-748c-4e27-b212-59e8cef9d6bf aborted: Block Device Mapping is Invalid.', u'code': 500, u'created': u'2018-01-31T03:10:56Z'}

The VM could not release the volume.

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Creating an Ansible Inventory file using Jinja templating

While there are lots of tools in Ansible for generating an inventory file dynamically, in a system like this, you might want to be able to perform additional operations against the same cluster. For example, once the cluster has been running for a few months, you might want to do a Yum update. Eventually, you want to de-provision. Thus, having a remote record of what machines make up a particular cluster can be very useful. Dynamic inventories can be OK, but often it takes time to regenerate the inventory, and that may slow down an already long process, especially during iterated development.

So, I like to generate inventory files. These are fairly simple files, but they are not one of the supported file types in Ansible. Ansible does support ini files, but the inventory files have maybe lines that are not in key=value format.

Instead, I use Jinja formatting to generate inventory files, and they are pretty simple to work with.

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Getting Shade for the Ansible OpenStack modules

When Monty Taylor and company looked to update the Ansible support for OpenStack, they realized that there was a neat little library waiting to emerge: Shade. Pulling the duplicated code into Shade brought along all of the benefits that a good refactoring can accomplish: fewer cut and paste errors, common things work in common ways, and so on. However, this means that the OpenStack modules are now dependent on a remote library being installed on the managed system. And we do not yet package Shade as part of OSP or the Ansible products. If you do want to use the OpenStack modules for Ansible, here is the “closest to supported” way you can do so.

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Using JSON home on a Keystone server

Say you have an AUTH_URL like this:

$ echo $OS_AUTH_URL

And now you want to do something with it.  You might think you can get the info you want from the /v3 url, but it does not tell you much:

$ curl $OS_AUTH_URL 
{"version": {"status": "stable", "updated": "2016-10-06T00:00:00Z", "media-types": [{"base": "application/json", "type": "application/vnd.openstack.identity-v3+json"}], "id": "v3.7", "links": [{"href": "", "rel": "self"}]}}[ayoung@ayoung541 salab]$

Not too helpful.  Turns out, though, that there is data, it is just requires the json-home accepts header.

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