Infrastructure as a Service provides virtual machines, virtualized storage, virtualized networking and the systems management tools to manage them.
IaaS is typically based on cheap commodity white label hardware. The philosophy is to keep the cost down by allowing the hardware to fail every now and then. Failed components are either replaced or simply removed from the pool of available resources.
IaaS provides simple, highly standardized building blocks to applications. It does not provide high availability, performance or security levels. Consequently, applications running on IaaS should be robust to allow for failing hardware and should be horizontally scalable to increase performance.
In order to use IaaS, users must create and start a new server, and then install an operating system and their applications. Since the cloud provider only provides basic services, like billing and monitoring, the user is responsible for patching and maintaining the operating systems and application software.
Not all operating systems and applications can be used in a IaaS cloud; many software licenses prohibit the use of a fully scalable, virtual environment like IaaS, where it is impossible to know in advance on which machines software will run.
This entry was posted on Vrijdag 28 Oktober 2016
In a traditional infrastructure deployment, compute, storage and networking are deployed and managed independently, often based on components from multiple vendors. In a converged infrastructure, the compute, storage, and network components are designed, assembled, and delivered by one vendor and managed as one system, typically deployed in one or more racks. A converged infrastructure minimizes compatibility issues between servers, storage systems and network devices while also reducing costs for cabling, cooling, power and floor space.
The technology is usually difficult to expand on-demand, requiring the deployment of another rack of infrastructure to add new resources. The following picture shows an example of a converged system.
While in a converged infrastructure the infrastructure is deployed as individual components in a rack, a hyperconverged infrastructure (HCI) brings together the same components within a single server node.
A hyperconverged infrastructure comprises a large number of identical physical servers from one vendor with direct attached storage in the server and special software that manages all servers, storage, and networks as one cluster running virtual machines.
The technology is easy to expand on-demand, by adding servers to the hyperconverged cluster. The following picture shows an example of a hyperconverged system.
Hyperconverged systems are an ideal candidate for deploying VDI environments (see section 12.3.3), because the storage is close to the compute (as it is in the same box) and the solution scales well with the rise of the number of users.
A big advantage of converged and hyperconverged infrastructures is having to deal with one firmware and software vendor. Vendors of hyperconverged infrastructures provide all updates for compute, storage and networking in one service pack and deploying these patches is typically much easier than deploying upgrades in all individual components in a traditional infrastructure deployment.
Drawbacks of converged and hyperconverged infrastructures are:
- Vendor lock-in – the solution is only beneficial if all infrastructure is from the same vendor
- Scaling can only be done in fixed building blocks – if more storage is needed, compute must also be purchased. This can have a side effect: since some software licenses are based on the number of used CPUs or CPU cores, adding storage also means adding CPUs and hence leads to extra license costs.
This entry was posted on Vrijdag 21 Oktober 2016
Object storage stores data in a flat address space. Data is stored and retrieved using RESTful API calls over HTTP. This in contrast with regular file systems, that store data in hierarchical, directory-based file systems that utilize specialized storage protocols.
Where a traditional file system provides a structure that simplifies locating files (for example, a log file is stored in /var/log/proxy/proxy.log), in object storage, a file’s location must be administered by the application using the object ID. For example, an application has administered that its log file has an object ID of 8932189023.
An object storage container stores the actual data (for example, a document, an image, or a video file), its metadata (for example, date, and size), and a unique Object ID. Amazon’s S3 service pioneered object storage and its protocol became the de facto standard protocol for object storage.
The flat address space in an object storage system enables simplicity and massive scalability of the storage system, as the Object ID is a link to a physical file that can be stored anywhere.
Data in object based storage typically can’t be modified. Instead, modified files must be deleted and rewritten, each time leading to a new Object ID that must be stored for reference in the application.
While object storage was not designed to be used as a file system, some systems emulate a file system using object storage. For instance, Amazon’s S3FS creates a virtual filesystem, based on S3 object storage, that can be mounted to an operating system in the traditional way.
This entry was posted on Vrijdag 07 Oktober 2016
Software Defined Networking (SDN) is a relatively new concept. It allows networks to be defined and controlled using software external to the physical networking devices.
With SDN, a relatively simple physical network can be programmed to act as a complex virtual network. It can become a hierarchical, complex and secured virtual structure that can easily be changed without touching the physical network components.
An SDN can be controlled from a single management console and open APIs can be used to manage the network using third party software. This is particularly useful in a cloud environment, where networks change frequently as machines are added or removed from a tenant’s environment. With a single click of a button or a single API call, complex networks can be created within seconds.
SDN works by decoupling the control plane and data plane from each other, such that the control plane resides centrally and the data plane (the physical switches) remain distributed, as shown in the next figure.
In a traditional switch or router, the network device dynamically learns packet forwarding rules and stores them in each device as ARP or routing tables. In an SDN, the distributed data plane devices are forwarding network packets based on ARP or routing rules that are loaded into the devices by an SDN controller devices in the central control plane. This allows the physical devices to be much simpler and more cost effective.
Network Function Virtualization
In addition to SDN, Network Function Virtualization (NFV) is a way to virtualize networking devices like firewalls, VPN gateways and load balancers. Instead of having hardware appliances for each network function, in NFV, these appliances are implemented by virtual machines running applications that perform the network functions.
Using APIs, NFV virtual appliances can be created and configured dynamically and on-demand, leading to a flexible network configuration. It allows, for instance, to deploy a new firewall as part of a script that creates a number of connected virtual machines in a cloud environment.
This entry was posted on Vrijdag 23 September 2016
Software Defined Storage (SDS) abstracts data and storage capabilities (the control plane) from the underlying physical storage systems (the data plane). This allows data to be stored in a variety of storage systems while being presented and managed as one storage pool to the servers consuming the storage. The figure below shows the SDS model.
Heterogeneous physical storage devices can be made part of the SDS system. SDS enables the use of standard commodity hardware, where storage is implemented as software running on commodity x86-based servers with direct attached disks. But the physical storage can also be a Storage Area Network, a Network Attached Storage system, or an Object storage system. SDS virtualizes this physical storage into one large shared virtual storage pool. From this storage pool, software provides data services like:
SDS provides servers with virtualized data storage pools with the required performance, availability and security, delivered as block, file, or object storage, based on policies. As an example, a newly deployed database server can invoke an SDS policy that mounts storage configured to have its data striped across a number of disks, creates a daily snapshot, and has data stored on tier 1 disks.
APIs can be used to provision storage pools and set the availability, security and performance levels of the virtualized storage. In addition, using APIs, storage consumers can monitor and manage their own storage consumption.
This entry was posted on Vrijdag 09 September 2016