Strong as a Bear

Flood of Drivers in Cinder

Thanks to its many new drivers, the Cinder block storage component appears in a positive light. For example, the software now supports direct connections to Fibre Channel storage and comes with native support for HP 3PAR and EMC storage (Figure 1).

Figure 1: The storage component Cinder comes with many new drivers, including drivers for Fibre Channel SANs.

New features have also been added: Just like Glance, Cinder can now handle multiple back ends at the same time. This feature is really useful, especially if you want to use both an existing SAN, and a new Ceph cluster simultaneously as back ends. Both backups and image cloning are now among the features that Cinder includes out of the box.

HA in Quantum

The network service Quantum impresses in Grizzly because it comes with a new component called the Quantum Scheduler. The scheduler allows you to have many different instances of the various Quantum services running simultaneously on multiple hosts. More specifically, it is possible to use several distributed DHCP and L3 agents at the same time. Scale out based on this principle removes the need for a single network node, which could be a bottleneck.

Moreover, the new feature for high availability is useful because the failure of the host with the network service no longer automatically affects all the VMs. Also, several alternative Quantum servers can take over the function of the failed server seamlessly.

Safety officers will be happy to hear that OpenStack now natively supports iptables at the Open vSwitch level. Security groups in Nova are officially classified as "abandoned," so Quantum is the sole ruler over network security.

The function that Quantum developers have really been beating the drum for is Load Balancing as a Service (LBaaS). Although this sounds like it came straight from the marketing department, in reality, it takes a very complex function directly to the heart of Quantum. Quantum can be used as a load balancer with LBaaS for different services, without having to set up a separate virtual server with the appropriate functionality. Quantum itself becomes the hardware load balancer and directly takes care of distributing packets across the various instances of a cloud in the network stack.

The Dashboard: A Lot of Quantum

The component with which most end users have the most contact is the dashboard (e.g., Horizon; Figure 2). For Horizon, the changes in Grizzly are all about Quantum because that was one of the largest construction sites in Essex after the release in October 2012.

Figure 2: What the user sees most often: the OpenStack dashboard.

Although the Quantum team did indeed complete an initial version of Quantum for Essex as promised, the dashboard knew nothing about it and was still designed to configure the network with Nova. Although the Nova developers created a partially functional workaround, in which they patched Nova so that it sent the appropriate commands to Quantum in Quantum setups (instead of making the network settings itself), in production environments, this nasty hack has proven to be very unreliable. For example, a patch is necessary for Folsom in Essex if the web interface is to understand floating IPs.

Grizzly puts an end to this hack because Horizon has been given a completely new back end and now understands Quantum perfectly. Thus, it is not surprising that the LBaaS function appears in the dashboard next to the basic functions. Even small corrections have been incorporated; for example, it is now possible to migrate VMs via the dashboard (Figure 3) and to display a graphical overview of the network topology.

Figure 3: With the new version, VM properties can be edited easily in the dashboard.