OpenStack cloud – pros and cons

The OpenStack platform is widely used in cloud computing; you have probably encountered this name while searching for a cloud solution for your business. We at SIM-Networks have been using OpenStack to create our cloud solutions for a long time, which is why we’re familiar with the specifics of this software. In this article, we will outline the basics of OpenStack, the main OpenStack advantages and disadvantages, the differences between OpenStack and its competitors, as well as some practical use-cases for OpenStack clouds.

What is OpenStack and how does it work?

OpenStack is a software package by Rackspace and NASA used to create cloud platforms. These instruments are available to every user free of charge and the code is open-source: the software can be modified for any individual needs. OpenStack clouds have commonalities between them; however, each particular product that uses this platform is unique.

Cloud platforms use the virtualization technology through hypervisors: virtual machines are created based on servers, and each of the machines uses a part of the resources provided by the physical equipment. However, virtualization is not enough to create a cloud: hypervisors do not ensure interaction between virtual machines. It is impossible to set up a common storage for multiple machines, control groups of instances or set up a network connection between them without using additional software.

Cloud architecture unites virtual machines into a single system. Each of them uses the resources of multiple physical servers; this kind of system is easy to scale. If you want to change the configuration of an instance, all you have to do is input the desired values in the control panel. This is impossible when using a physical server or a non-cloud virtual server (VPS): a user will have to buy new components or redeploy the VPS.

Other cloud platform benefits include high fault tolerance, decentralized access to resources and data, simple management, increased security due to distributed data storage etc. The main task of OpenStack is to provide those features on the basic level and to provide tools to the developers that wish to create their own IaaS (Infrastructure-as-a-Service) platform.

What components make up OpenStack?

The OpenStack software package consists of multiple element responsible for specific aspects of working with a cloud platform. These aspects include instance management, security, data storage etc. OpenStack cloud developers highlight 7 main components necessary for the cloud to function; let’s look into them in more detail.

Nova – a key instrument that control the pool of computing resources in the cloud. This service provides users with the main functionality of a cloud platform, meaning the ability to create virtual machines and change their configurations «on the fly» along with the hypervisor.

Neutron – a service responsible for the virtual network infrastructure of the cloud. Neutron ensures interaction between instances, enables the creation of virtual networks, helps set up VPN and firewalls.

Glance – a service for managing software images. Images (meaning virtual data carriers) are used to install software onto virtual machines. Glance arranges these images into a library to make it quicker and easier for users to prepare virtual machines for specific tasks.

Keystone – a service used to authenticate connections and distribute user rights in the cloud. This service is used to provide and restrict access to resources and the functionality of other components through authorizing the user.

Cinder – block storage based on the cloud’s resources. Block storage is a data storage technology often used with virtualized platforms due to its high performance when working with large volumes of data. In principle, Cinder is the equivalent of a regular hard drive.

Swift – object storage with support for distributed data storage. Unstructured data can be stored on multiple hard drives; Swift will display it as a whole. This service also deletes data duplicates automatically to save space in the storage.

Horizon – the graphical OpenStack cloud management interface for the end user. This instrument can be used to create instances, change their configurations, set access rights and use the functionality of other OpenStack components.

OpenStack pros and cons

The main benefit of OpenStack is flexibility due to its open-source philosophy. Plenty of cloud providers use this package as the basis for their products; however, the specific offers vary widely. If needed, a provider can adjust the modules to adapt to the specific needs of their client base. This is impossible when using proprietary software such as VMware vCloud. Let’s take a look at an example of such a modification – the SIM-Cloud Dashboard service based on the Horizon component. If you wish to see an example of an OpenStack cloud interface, read the news item regarding the SIM-Networks public cloud interface update.

The modular structure of OpenStack also lends itself to flexible usage. Apart from the main components, users can add services for other tasks: modules for reserve copying, working with containers, balancing workloads etc. This means that OpenStack offers a stack of solutions for practically any aspect of working in the cloud. This sets OpenStack apart from its competitor, OpenNebula; the latter offers an integrated system instead of a module package.

These advantages have a flip side: the developers don’t offer proper technical support. Each OpenStack cloud is largely unique, which is why solving the problems of individual users would take too much time. Thankfully, this downside is unlikely to affect the experience of the end IaaS user; when you order an OpenStack cloud from a provider, you get the technical support of the specialists who developed that particular solution. Additionally, the documentation for each service is freely available on the OpenStack website.

In general, the disadvantages of OpenStack affect cloud providers more than they do end users. The platform evolves dynamically: old services lose relevance and are phased out while the main modules get regular updates. An OpenStack cloud needs to be constantly modernized so that users get the latest functionality offered by the platform. For this reason, the quality of the cloud solution largely depends of the provider rather the platform itself. For example, the SIM-Networks cloud is updated yearly.

OpenStack cloud use-cases

SIM-Networks specialists have been using OpenStack in cloud computing platforms ever since the public SIM-Cloud was released; we also create private clouds based on this software. During this time, we’ve encountered a number of use-cases for clouds that use this software package. Let us look into a couple of examples.

OpenStack cloud for a business from scratch

The client’s task was to migrate services into a cloud infrastructure based on Widnows OS instances. As a rule, clients prefer to leave cloud management to the provider; in this case, the client preferred that IT infrastructure management be left to their staff. We guided the client’s staff through the basics of OpenStack cloud management as part of the project.

Our technical specialists migrated 19 of the client’s virtual machines. The total volume of data that had to be transferred was 3 TB of fast disk space 8 TB of slow disk space. Network connections were set up between the client’s office and the cloud platform, as well as between the cloud and the devops platform. The client’s staff carried out the preliminary setup of the cloud on their own using skills learned from SIM-Networks experts and started working in the cloud.

Public cloud as an estimation tool for building a private cloud

The client was planning to migrate their IT services into a private cloud. Such a project requires significant investment and takes plenty of time, which is why the client wanted to evaluate the actual need in resources for the future IT infrastructure beforehand. We offered to use an OpenStack public cloud as a tool for the pre-project evaluation. The plan was to deploy the client’s existing services in the cloud and evaluate the amount of resources needed for the private cloud through practice.

We carried out the OpenStack cloud migration and scaled the client's services as the business grew. This process was simple due to the solution’s architecture: the instances were reconfigured as soon as the need arose. During this period, we optimized the solution to match the specific needs of the client’s tasks. When the client was satisfied with the IT infrastructure, we audited the resources and created a private cloud based on this data.

Should I order an OpenStack cloud?

OpenStack is a software package with a reliable reputation on the cloud solution market. The product is constantly updated to match the development of cloud technology. However, the quality of a solution based on this platform depends on the developers of the cloud itself; it’s better to evaluate the specific offers of cloud providers than to choose a cloud simply because it uses OpenStack. Nonetheless, OpenStack is easy to modify, which is why it’s often used by providers that focus on solving actual problems faced by clients.

Individual solutions are the specialization of SIM-Networks. For that reason, we chose OpenStack as the basis for our public cloud. The concept of public infrastructure implies universality; however, the ability to modify services allows us to update the product to match the needs of users. We also build custom private clouds from scratch using this platform. If you want to learn more, get acquainted with the public SIM-Cloud and SIM-Networks private clouds.

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