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Category Archives for "Systems"

Ubuntu, cloud-init, and OpenStack Heat

In this post I’d like to share a couple of things I recently learned about the interaction between cloud-init and OpenStack Orchestration (aka “Heat”). This may be stuff that you already know, but in the interest of helping others who may not know I’m posting it here.

One issue that I’d been repeatedly running into was an apparent “failure” on the part of Heat to properly apply cloud-init configurations to deployed Ubuntu instances. So, using a Heat template with an OS::Nova::Server resource defined like this would result in an instance that apparently wasn’t reachable via SSH (I’d get back Permission denied (publickey)):

resources:
  instance0:
    type: OS::Nova::Server
    properties:
      name: cloud-init-test-01
      image: { get_param: image_id }
      flavor: m1.xsmall
      networks:
        - port: { get_resource: instance0_port0 }
      key_name: lab

Deploying an instance manually from the same image worked perfectly. So what was the deal?

The first thing I learned was that, in some circumstances (more on this in a moment) defaults to injecting SSH keys (like the key named lab specified in the template) to a user account named “ec2-user”. Ah! I’d been using the default “ubuntu” account specified in Continue reading

Cisco VIRL NXOSv NXAPI Update

Cisco officially announced the April release of Cisco VIRL the announcement and upgrade instructions can be found here. Some of the highlights from the upgrade are: ISOv is now up to version 15.2(2)T...

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Running Photon on Fusion via Vagrant

Most of you have probably picked up on the news of VMware’s new container-optimized Linux distribution, code-named “Photon”. (More details here.) In this post, I’m going to provide a very quick walkthrough on running Photon on VMware Fusion via Vagrant. This walkthrough will leverage a Vagrant box for Photon that has already been created.

To make things easier, I’ve added a photon directory to my GitHub “learning-tools” repository. Feel free to pull those files down to make it easier to follow along.

I assume that you’ve already installed Vagrant, VMware Fusion, and the Vagrant plugin for VMware. If you haven’t, you’ll want to complete those tasks—and verify that everything is working as expected—before proceeding.

  1. Install an additional Vagrant plugin that enables Vagrant to better detect and interact with Photon using this command:

     vagrant plugin install vagrant-guests-photon

    If you don’t install this plugin, you’ll likely get a non-fatal error about Vagrant being unable to perform the networking configuration. (Review the GitHub repository for this plugin if you want/need more details. Also, note that a PR against Vagrant to eliminate the need for this plugin was opened and merged; this fix should show up in a future release of Vagrant.)

  2. Continue reading

Running an etcd-Backed Docker Swarm Cluster

In this post, I’ll build on a couple of previous posts and show you how to build your own Docker Swarm cluster that leverages etcd for cluster node discovery. This post builds on the information presented on how to run an etcd 2.0 cluster on Ubuntu as well as the information found in this post on running a Consul-backed Docker Swarm cluster.

To help you follow along, I’ve created a Vagrant environment that you can use to turn up the configuration described in this blog post. These files are found in the “docker-swarm-etcd” directory of my GitHub learning-tools repository. Feel free to use the files in this directory/repository to help with the learning process.

There are 3 major components to this configuration:

  1. A cluster of three Ubuntu 14.04 systems running etcd 2.0 (specifically, etcd 2.0.9, the last release as of this writing). This etcd cluster serves as a discovery back-end for Docker Swarm.
  2. A set of hosts running the Docker daemon (version 1.4.0 or higher, as required by Swarm). In this particular instance, I’m using CoreOS Linux (version 557.2.0 from the stable branch).
  3. A few containers running on the CoreOS hosts; Continue reading

Running an etcd 2.0 Cluster on Ubuntu 14.04

In this post, I’m going to show you how to set up a cluster of three nodes running etcd 2.0 (specifically, etcd 2.0.9). While I’ve discussed etcd before, that was in the context of using etcd with CoreOS Linux. In this case, I’ll use Ubuntu 14.04 as the base OS, along with the latest released version of etcd.

To help you follow along, I’ve created a set of files that will allow you to use Vagrant to turn up an etcd 2.0 cluster on Ubuntu 14.04 (on your laptop, if so desired). You can find all these files in the “etcd-2.0” directory of my learning-tools GitHub repository.

Installing the Base OS

You don’t need anything special when setting up etcd; a straightforward Ubuntu Server 14.04 x64 installation will work just fine. If you’re using the files in my learning-tools repository, you’ll see that Vagrant simply turns up a VM based on a plain-jane Ubuntu 14.04 box. If you’re building this from scratch (why?!), simply create a VM and install Ubuntu 14.04 into it. As long as it has Internet connectivity, that’s all that’s needed.

Installing etcd

Installing etcd Continue reading

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