Reconfigure a Dell RAID (PERC) Controller with racadm

Wednesday, September 3, 2014

While setting up an OpenStack Swift cluster, I had five Dell R720 servers with incorrectly configured RAID arrays. The two operating system hard drives were configured in a RAID1 array, as expected, but the 24 data hard drives were configured in two RAID5 arrays. The data hard drives in the OpenStack Swift storage nodes should not be in a RAID array; Swift simply wants each hard drive on its own.

You can reboot most of Dell’s enterprise servers into the Dell RAID (PERC) Controller to get access to a GUI to re-configure the RAID arrays. But, with five servers and 24 disks on each, using the GUI would have been a very tedious and time consuming task. So, I began looking into what the racadm command was capable of.

You can SSH to the IP address of a Dell iDRAC and use the racadm command to run all sorts of commands. Luckily, racadm has a set of commands that allow you to reconfigure the RAID arrays.

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Configure Multiple Network Interfaces on an OpenStack Instance

Wednesday, September 3, 2014

Most of the pre-made OpenStack Cloud Images are created to attach an OpenStack Instance to one network interface on creation of the instance.

As of OpenStack Icehouse, the functionality to attach another network interface to an existing OpenStack Instance through the Horizon Dashboard is not exposed. However, you can of course attach another network interface to an existing OpenStack Instance using the neutron and nova commands.

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Delete Duplicate OpenStack Hypervisors and Services

Sunday, August 3, 2014

If you ever change the hostname of any of your OpenStack nodes and restart the OpenStack services on those nodes, the services are going to re-register to the OpenStack cluster under the new hostname. Because of this, when you run nova hypervisor-list, nova service-list, neutron agent-list, or cinder service-list you are going to have duplicate entries.

Unfortunately, there are not commands to clean up duplicate entries, so you have to modify the various OpenStack databases by hand.

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Questions to Ask to Determine if Your Application is Cloud Ready

Sunday, August 3, 2014

Anyone working in IT has heard the question, “is your application cloud ready?”. What on earth does it mean? What factors go into making an application “cloud” ready?

Applications can be architected in many different ways and there are arguably many factors that go into making an application “cloud” ready.

This post isn’t going to cover what those factors are. What’s more interesting to me is how to quickly figure out if an application is “cloud” ready. I have found that there are a series of questions that can be asked to quickly determine this.

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Use OpenStack Swift as a Backend Store for Glance

Sunday, August 3, 2014

By default, OpenStack Glance saves images and OpenStack Instance snapshots on the local filesystem in /var/lib/glance/images/.

However, if you have a Swift Cluster, you can just as easily use it to save images and snapshots instead of the local filesystem where Glance is running.

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OpenStack Swift 401 Unauthorized When Using the swift Command

Wednesday, July 16, 2014

After setting up a Swift Cluster with TempAuth, I wanted to remove TempAuth and use Keystone to authenticate. However, I kept encountering 401 Unauthorized errors when running the swift command even though I was fairly certain everything was configured properly.

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Authenticate OpenStack Swift Against Keystone Instead of TempAuth

Wednesday, July 16, 2014

In a previous post I detailed how to install a stand-alone, multi-node OpenStack Swift Cluster with VirtualBox or VMware Fusion and Vagrant. That post configures Swift’s TempAuth module for authentication. However, if you have an existing OpenStack environment, or just an OpenStack Keystone server already setup, you can just as easily use Keystone instead.

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Install a Stand-alone, Multi-node OpenStack Swift Cluster with VirtualBox or VMware Fusion and Vagrant

Monday, July 14, 2014

The OpenStack Swift developer website describes Swift best: it is a highly available, distributed, eventually consistent object/blog store. Organizations can use Swift to store lots of data efficiently, safely, and cheaply.

For being such a powerful object storage platform, I found it surprisingly easy to setup and configure. Of course, setup becomes more difficult as the number of nodes, racks, and data centers increase.

But, not all of us have many nodes, racks, or data centers at our disposal, and simply want to setup an environment to play with on our workstation.

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From Bare Metal to Rackspace Private Cloud POC

Monday, June 23, 2014

There are all sorts of tools available to setup virtual OpenStack environments on your workstation.

In Rackspace Private Cloud’s case, the following three options are available:

These tools are great to give you a very quick and easy way to setup a demo Rackspace Private Cloud environment to begin learning how the services, APIs, CLI tools, and Horizon Dashboard work. However, these demo environments do not give you a realistic expectation of what you can expect Rackspace Private Cloud to do for you on bare metal servers or how to actually set it all up.

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Do Not Use Shared Storage for OpenStack Instances

Saturday, June 14, 2014

With the advent of cloud computing came the cloud computing methodology and a different way of doing things. Instead of having high availability just at the infrastructure layer, high availability now needs to exist at the infrastructure layer and the application layer. And even though the infrastructure layer is architected to be highly available, your application should be designed to expect something at the infrastructure layer to fail. And when something does fail, whatever failed should not bring anything else down with it. This is a shared-nothing architecture.

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