OpenStack

How to install Red Hat OpenShift 3.11 on OpenStack 13

How to install Red Hat OpenShift 3.11 on OpenStack 13

Red Hat OpenShift Container Platform is a platform-as-a-service (PaaS). It orchestrates and manages containerized applications through Kubernetes. Although OpenShift Container Platform supports cloud-native applications, it also supports custom-built applications. OpenShift Container Platform can run on a hybrid cloud configuration providing the flexibility to expand and grow.

Red Hat OpenStack Platform is an infrastructure-as-a-service (IaaS). This means it is a cloud-based platform that provides virtual servers and other resources. Users either manage it through a web-based dashboard, through command-line tools, or through RESTful web services.

If you are considering Red Hat OpenShift Container Platform on OpenStack Platform, there are several advantages, including easily increasing the number of compute nodes and using dynamic storage.

In this article, I will outline the main points required to successfully install Red Hat OpenShift Container Platform on OpenStack Platform. Because my OpenStack knowledge is limited, I reached out to my colleagues for help and will not address too many OpenStack technical details here.

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Speeding up Open vSwitch with partial hardware offloading

Speeding up Open vSwitch with partial hardware offloading

Open vSwitch (OVS) can use the kernel datapath or the userspace datapath. There are interesting developments in the kernel datapath using hardware offloading through the TC Flower packet classifier, but in this article, the focus will be on the userspace datapath accelerated with the Data Plane Development Kit (DPDK) and its new feature—partial flow hardware offloading—to accelerate the virtual switch even more.

This article explains how the virtual switch worked before versus now and why the new feature can potentially save resources while improving the packet processing rate.

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Performance improvements in OVN: Past and future

Performance improvements in OVN: Past and future

OVN (Open Virtual Network) is a subcomponent of Open vSwitch (OVS). It allows for the expression of overlay networks by connecting logical routers and logical switches. Cloud providers and cloud management systems have been using OVS for many years as a performant method for creating and managing overlay networks.

Lately, OVN has come into its own because it is being used more in Red Hat products. The result has been an increased amount of scrutiny for real-world scenarios with OVN. This has resulted in new features being added to OVN. More importantly, this has led to tremendous changes to improve performance in OVN.

In this article, I will discuss two game-changing performance improvements that have been added to OVN in the past year, and I will discuss future changes that we may see in the coming year.

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IP packet buffering in OVN

IP packet buffering in OVN

Open Virtual Network (OVN) is a subproject of Open vSwitch (OVS), a performant, programmable, multi-platform virtual switch. OVN adds to the OVS existing capabilities the support for overlay networks by introducing virtual network abstractions such as virtual switches and routers. Moreover, OVN provides native methods for setting up Access Control Lists (ACLs) and network services such as DHCP. Many Red Hat products, such as Red Hat OpenStack Platform and Red Hat Virtualization, are now using OVN, and Red Hat OpenShift Container Platform will be using OVN soon.

In this article, I’ll cover how OVN ARP/ND_NS actions work, the main limitations in the current implementation, and how to overcome those. First, I’ll provide a brief overview of OVN’s architecture to facilitate the discussion:

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How to create an Open Virtual Network distributed gateway router

How to create an Open Virtual Network distributed gateway router

In this article, I discuss external connectivity in Open Virtual Network (OVN), a subproject of Open vSwitch (OVS), using a distributed gateway router.

OVN provides external connectivity in two ways:

  • A logical router with a distributed gateway port, which is referred to as a distributed gateway router in this article
  • A logical gateway router

In this article, you will see how to create a distributed gateway router and an example of how it works.

Creating a distributed gateway router has some advantages over using a logical gateway router for the CMS (cloud management system):

  • It is easier to create a distributed gateway router because the CMS doesn’t need to create a transit logical switch, which is needed for a logical gateway router.
  • A distributed gateway router supports distributed north/south traffic, whereas the logical gateway router is centralized on a single gateway chassis.
  • A distributed gateway router supports high availability.

Note: The CMS can be OpenStack, Red Hat OpenShift, Red Hat Virtualization, or any other system that manages a cloud.

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Troubleshooting FDB table wrapping in Open vSwitch

Troubleshooting FDB table wrapping in Open vSwitch

When most people deploy an Open vSwitch configuration for virtual networking using the NORMAL rule, that is, using L2 learning, they do not think about configuring the size of the Forwarding DataBase (FDB).

When hardware-based switches are used, the FDB size is generally rather large and the large FDB size is a key selling point. However for Open vSwitch, the default FDB value is rather small, for example, in version 2.9 and earlier it is only 2K entries. Starting with version 2.10 the FDB size was increased to 8K entries. Note that for Open vSwitch, each bridge has its own FDB table for which the size is individually configurable.

This blog explains the effects of configuring too small an FDB table, how to identify which bridge is suffering from too small an FDB table, and how to configure the FDB table size appropriately.

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Debugging Memory Issues with Open vSwitch DPDK

Debugging Memory Issues with Open vSwitch DPDK

Introduction

This article is about debugging out-of-memory issues with Open vSwitch with the Data Plane Development Kit (OvS-DPDK). It explains the situations in which you can run out of memory when using OvS-DPDK and it shows the log entries that are produced in those circumstances. It also shows some other log entries and commands for further debugging.

When you finish reading this article, you will be able to identify that you have an out-of-memory issue and you’ll know how to fix it. Spoiler: Usually having some more memory on the relevant NUMA node works. It is based on OvS 2.9.

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Open vSwitch-DPDK: How Much Hugepage Memory?

Open vSwitch-DPDK: How Much Hugepage Memory?

Introduction

In order to maximize performance of the Open vSwitch DPDK datapath, it pre-allocates hugepage memory. As a user you are responsible for telling Open vSwitch how much hugepage memory to pre-allocate. The question of exactly what value to use often arises. The answer is, it depends.

There is no simple answer as it depends on things like the MTU size of the ports, the MTU differences between ports, and whether those ports are on the same NUMA node. Just to complicate things a bit more, there are multiple overheads, and alignment and rounding need to be accounted for at various places in OVS-DPDK. Everything clear? OK, you can stop reading then!
However, if not, read on.

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Build your Software Defined Data Center with Red Hat CloudForms and Openstack – part 2

Build your Software Defined Data Center with Red Hat CloudForms and Openstack – part 2

Welcome back, here we will continue with the second part of my post, where we will work with Red Hat Cloudforms. If you remember, in our first post we spoke about Red Hat OpenStack Platform 11 (RHOSP). In addition to the blog article, at the end of this article is also a demo video I created to show to our customers/partners how they can build a fully automated software data center.

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