Openstack on sysarcher/@ich_codehttps://sysarcher.github.io/categories/openstack/Recent content in Openstack on sysarcher/@ich_codeHugoen-usTue, 10 Nov 2020 21:22:37 +0200VM Optimizations for RThttps://sysarcher.github.io/posts/realtime-linux-vms/Tue, 10 Nov 2020 21:22:37 +0200https://sysarcher.github.io/posts/realtime-linux-vms/<p>QEMU/KVM are a popular backend for OpenStack. In StarlingX Openstack (<code>stx-openstack</code>) this is also the case. I&rsquo;ll try to describe various techniques that I used to optimize RT behavior on an STX 4.0.1 cluster with worker nodes.</p> <h4 id="terminology">Terminology</h4> <p><strong>Bare-Metal</strong> is a a physical computer and it&rsquo;s base OS</p> <p><strong>Host</strong> is a bare-metal machine that runs VMs</p> <p><strong>Thread</strong> is a core of a CPU</p> <p><strong>CPU thread</strong> refers to the thread on the host system CPU</p>QEMU/KVM are a popular backend for OpenStack. In StarlingX Openstack (stx-openstack) this is also the case. I’ll try to describe various techniques that I used to optimize RT behavior on an STX 4.0.1 cluster with worker nodes.

Terminology

Bare-Metal is a a physical computer and it’s base OS

Host is a bare-metal machine that runs VMs

Thread is a core of a CPU

CPU thread refers to the thread on the host system CPU

vCPU thread is a thread on a VM’s virtualized CPU

Note: I borrowed terminology heavily from this article on null-src

Isolating CPUs

My last article covers this topic. Isolating a VM’s vCPU threads from the host system ensures that host’s processes don’t interfere with the VM.

Scheduling Openstack VMs on isolated cores

CPU Affinity

using taskset

Linux Process Scheduler Tuning

GRUB cmdline

Okay… don’t delete the console entries in your command line… the entries below are for isolated cpu 1. This is not a comprehensive list… Just append whatever makes sense to you.

GRUB_CMDLINE_LINUX_DEFAULT="threadirqs rcu_nocbs=1 rcu_nocb_poll isolcpus=1 nohz_full=1 nohz=off intel_pstate=disable nosoftlockup nohalt"
]]>First Steps With OpenStackhttps://sysarcher.github.io/posts/openstack-deployment/Fri, 26 Apr 2019 21:22:37 +0200https://sysarcher.github.io/posts/openstack-deployment/<p>I recently tried to set up OpenStack on a single-node development environment using devstack. This blog is <em>not</em> meant as a tutorial or getting started guide. However, I hope that Google will send someone crying tears of sorrow this way so he can benefit from my experience.</p> <h3 id="conclusion">Conclusion</h3> <p>What I concluded from the documentations is that we don&rsquo;t get something ready-to-go from the official docs. And you should consider yourself lucky if everything worked for you out-of-the-box.</p>I recently tried to set up OpenStack on a single-node development environment using devstack. This blog is not meant as a tutorial or getting started guide. However, I hope that Google will send someone crying tears of sorrow this way so he can benefit from my experience.

Conclusion

What I concluded from the documentations is that we don’t get something ready-to-go from the official docs. And you should consider yourself lucky if everything worked for you out-of-the-box.

Setup Ideas

  • Start from a clean installation of Ubuntu 18.04.
  • The local.conf goes into the top-level directory of the devstack checkout.

Setup

My setup already provided the DNS and DHCP servers as illustrated below.

        (DNS Server)              (DHCP Server)
             |                          |
             |                          |
             +------------+-------------+
                          |
                          |
                        (OpenStack)

So, my local.conf looks like the following:

[[local|localrc]]
ADMIN_PASSWORD=safeandsecure
DATABASE_PASSWORD=$ADMIN_PASSWORD
RABBIT_PASSWORD=$ADMIN_PASSWORD
SERVICE_PASSWORD=$ADMIN_PASSWORD

HOST_IP=<HOST_IP>

FLOATING_RANGE=<HOST_IP>/24
Q_FLOATING_ALLOCATION_POOL=start=<HOST_IP>.150,end=<HOST_IP>.200
FIXED_RANGE=10.11.12.0/24
FIXED_NETWORK_SIZE=256
PUBLIC_INTERFACE=eno1
PUBLIC_NETWORK_GATEWAY=<HOST_IP>.1

LOGFILE=$DEST/logs/stack.sh.log
LOGDAYS=2

SWIFT_HASH=66a3d6b56c1f479c8b4e70ab5c2000f5
SWIFT_REPLICAS=1
SWIFT_DATA_DIR=$DEST/data

(The <HOST_IP>.XXX numbers are obviously replacing the last part of the IP address.)

What I’m telling OpenStack is that I …

  • already have a Gateway in the network, use it!
  • Already know what the IP allocation pool looks like

Next

With that, hopefully you can go do OpenStack stuff and not have to worry about networking being the biggest issue in your life. Good luck!!!

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