Operating Open vSwitch brings a new set of challenges. One of those challenges is managing Open vSwitch itself and making sure you’re up to date with performance and stability fixes. For example, in late 2013 there were significant performance improvements with the release of 1.11 ( flow wildcarding!) and in the 2.x series there are even more improvements coming. This means everyone running those old versions of OVS (I’m looking at you, <=1....
This post is a deep dive into what happens in Nova (and where in the code) when a console URL is retrieved via the nova API for a Nova configuration backed by XVP and XenServer/XenAPI. Hopefully the methods used in Nova’s code will not change over time, and this guide will remain good starting point. Example nova client call: [code]nova get-vnc-console [uuid] xvpvnc[/code] And the call returns: +--------+-------------------------------------------------------------------------------------------------------+ | Type | Url | +--------+-------------------------------------------------------------------------------------------------------+ | xvpvnc | https://URL:PORT/console?...
This post is a collection of useful articles/videos that I’ve collected about networking on XenServer and Linux. XenServer Xen Network Throughput and Performance Guide (Technical Overview) XenServer: Under the Hood < Specifically device -> PIF -> network -> VIF relationship Linux (video) Through the Ether and Back Again < discusses python and the Linux Sockets API How SKBs work Queueing in the Linux Network Stack Linux Advanced Routing & Traffic Control HOWTO Linux Device Drivers 3rd Edition < specifically chapter 17 As you can see, there are a multitude of elements to consider when looking into host networking issues for a Linux VM running on XenServer (which is Linux underneath the covers anyway)....
In the physical world when you power on a server it’s already cabled (hopefully). With VMs things are a bit different. Here’s the sequence of events when a VM is started in Nova and what happens on XenServer to wire it up with Open vSwitch. nova-compute starts the VM via XenAPI XenAPI VM.start creates a domain and creates the VM’s vifs on the hypervisor The Linux user device manager manages receives this event, and scripts within /etc/udev/rules....
Hardware: Dell XPS 8500 Intel i5 RAM + SSD upgrades from Crucial Local Storage (1T) Software: Fedora Core 18 (base OS) VirtualBox Vagrant DevStack XenServer 6 I’m setting up a home lab to do some light coding on OpenStack and for testing implementations of next generation software/hardware deployment tools like BOSH and Razor.
Based on currently available code (nova: a77c0c50166aac04f0707af25946557fbd43ad44 2012-11-02/python-glanceclient: 16aafa728e4b8309b16bcc120b10bc20372883f4 2012-11-07/glance: 9dae32d60fc285d03fdb5586e3368d229485fdb4) This is a deep dive into what happens (and where in the code) during image creation with a Nova/Glance configuration that is backed by XenServer/XenAPI. Hopefully the methods used in Glance/Nova’s code will not change over time, and this guide will remain good starting point. Disclaimer: I am _not_ a developer, and these are really just best guesses. Corrections are welcome....
Based on currently available code ( a77c0c50166aac04f0707af25946557fbd43ad44 2012-11-02) This is a deep dive into what happens (and where in the code) during a rescue/unrescue scenario with a Nova configuration that is backed by XenServer/XenAPI. Hopefully the methods used in Nova’s code will not change over time, and this guide will remain good starting point. Rescue nova-api receives a rescue request. A new admin password is generated via utils.generate_password meeting FLAGS.password_length length requirement....
Based on the currently available code ( commit 114109dbf4094ae6b6333d41c84bebf6f85c4e48 – 2012-09-13) This is a deep dive into what happens (and where in the code) during a resize down (e.g., flavor 4 to flavor 2) with a Nova configuration that is backed by XenServer/XenAPI. Hopefully the methods used in Nova’s code will not change over time, and this guide will remain good starting point. Steps 1-6a are identical to my previous entry " Deep dive: OpenStack Nova Resize Up with XenAPI/Xenserver"....
Nova is the Compute engine of the OpenStack project. Based on the currently available code ( commit 114109dbf4094ae6b6333d41c84bebf6f85c4e48 - 2012-09-13) This is a deep dive into what happens (and where in the code) during a resize up (e.g., flavor 2 to flavor 4) with a Nova configuration that is backed by XenServer/XenAPI. Hopefully the methods used in Nova’s code will not change over time, and this guide will remain good starting point....