Author Archives: Dan

Evacuate in nova: one command to confuse us all

If you’ve ever used OpenStack Nova, you’ve probably at least seen our plethora of confusing commands that involve migrating instances away from a failing (or failed) compute host. If you are brave, you’ve tried to use one or more of … Continue reading

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Upgrades in Nova: Database Migrations

This is a part of a series of posts on the details of how Nova supports live upgrades. It focuses on one of the more complicated pieces of the puzzle: how to do database schema changes with minimal disruption to … Continue reading

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Upgrades in Nova: Objects

This is a part of a series of posts on the details of how Nova supports live upgrades. It focuses on a very important layer that plays several roles in the system, providing a versioned RPC and database-independent facade for … Continue reading

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Upgrades in Nova: RPC APIs

This is a part of a series of posts on the details of how Nova supports live upgrades. It focuses on the very important task of doing proper versioning and handling compatibility in your RPC APIs, which is a baseline … Continue reading

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Upgrades in Nova: The Details

Over the last few years, the Nova project has spent a lot of time on improving its story around live upgrades. We’ve made a lot of progress and done so with minimal disruption as we were figuring out how to … Continue reading

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Upgrading Nova to Kilo with minimal downtime

Starting in Icehouse, Nova gained the ability to do partial live upgrades. This first step meant that control services (which are mostly stateless) could be upgraded along with database schema before any of the compute nodes. After that step was … Continue reading

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Execuhitch on a 2012 BMW X5 M-Sport

Apparently, the X5 is about the most complicated “utility vehicle” to use for towing. I don’t know why BMW doesn’t make this easier, but they don’t. Their OEM hitch option is clearly an afterthought and looks terrible, especially on an … Continue reading

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2007 Audi A4 LED DRL Conversion

There is no shortage of writeups online about converting a B7’s ugly yellow daytime running lights to LEDs. It was Nick’s that made me decide to do the actual conversion, and part of the reason why I decided to add … Continue reading

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The magical sleeping development machine

For years now, I’ve preferred to do all my development on a dedicated machine. This means my desktop (or laptop, depending) is just a glorified terminal-and-editor-running appliance. It probably comes from years of crashing boxes during kernel development, but it … Continue reading

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Multi-room audio with multicast RTP

Our house has speakers in the ceiling in almost every room. This is not something I’ve had before, and was initially skeptical about usefulness and fidelity. However, I’ve actually been enjoying having the background music while working be spread further … Continue reading

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