Arie Bregman

Linux And Stuff

Author: bregman (page 2 of 8)

OpenStack: Neutron Service Code Deep Dive

This post is a dummy walkthrough of neutron services code. I recommend being familiar with the following modules (not a hard requirement, but will help you avoid jumping between this post and other docs):

I created the following drawing to make it easier to track several of the files and classes mentioned in this post.

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InfraRed: Deploying and Testing Openstack just made easier!

Deploying and testing OpenStack is very easy

If you read the headline and your eyebrows raised, you are at the right place. I believe that most of us, who experienced at least one deployment of OpenStack, will agree that deploying OpenStack can be a quite frustrating experience. It doesn’t matter if you are using it for debugging your code or it’s an integral part of your CI environment, deploying OpenStack often with changes, can be complex. Let’s stop for a minute and think why it’s like that.

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TripleO: Debugging Overcloud Deployment Failure

You run ‘openstack overcloud deploy’ and after a couple of minutes you find out it failed and if that’s not enough, then you open the deployment log just to find a very (very!) long output that doesn’t give you an clue as to why the deployment failed. In the following sections we’ll see how can we get to the root of the problem.

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Python: check if two strings are permutations of each other

Another question I cover in a presentation I’m preparing for “Open University meets Open Source” meetups.

What is a Permutation?

Permutation is the action of rearranging objects, characters or symbols into different, unique sequences.

Each sequence is called ‘permutation’.

It’s common to see people mix permutation with combination, but those are two different things. Remember, combination doesn’t care about the order, while permutation does.

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Python: check if one string is a rotation of another string

Another question I cover in a presentation I’m preparing for “Open University meets Open Source” meetups.

The question

You have two strings, str1 and str2 and you need to return True if the first string is a rotation of the second string. Otherwise, return False.

Examples

“hello”,    “llohe” -> True. If we’ll rotate the second string twice, you’ll get ‘hello’.

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