Cloud hosting, Cloud computing - web app, server, vps
Cloud computing is a recently evolved computing terminology or metaphor based on utility and consumption of computing resources. Cloud computing involves deploying groups of remote servers and software networks that allow centralized data storage and online access to computer services or resources. Clouds can be classified as public, private or hybrid.
Cloud computing relies on sharing of resources to achieve coherence and economies of scale, similar to a utility (like the electricity grid) over a network. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services.
Cloud computing, or in simpler shorthand just "the cloud", also focuses on maximizing the effectiveness of the shared resources. Cloud resources are usually not only shared by multiple users but are also dynamically reallocated per demand. This can work for allocating resources to users. For example, a cloud computer facility that serves European users during European business hours with a specific application (e.g., email) may reallocate the same resources to serve North American users during North America's business hours with a different application (e.g., a web server). This approach should maximize the use of computing power thus reducing environmental damage as well since less power, air conditioning, rack space, etc. are required for a variety of functions. With cloud computing, multiple users can access a single server to retrieve and update their data without purchasing licenses for different applications.
The term "moving to cloud" also refers to an organization moving away from a traditional CAPEX model (buy the dedicated hardware and depreciate it over a period of time) to the OPEX model (use a shared cloud infrastructure and pay as one uses it).
Proponents claim that cloud computing allows companies to avoid upfront infrastructure costs, and focus on projects that differentiate their businesses instead of on infrastructure. Proponents also claim that cloud computing allows enterprises to get their applications up and running faster, with improved manageability and less maintenance, and enables IT to more rapidly adjust resources to meet fluctuating and unpredictable business demand. Cloud providers typically use a "pay as you go" model. This can lead to unexpectedly high charges if administrators do not adapt to the cloud pricing model.
The present availability of high-capacity networks, low-cost computers and storage devices as well as the widespread adoption of hardware virtualization, service-oriented architecture, and autonomic and utility computing have led to a growth in cloud computing.
Cloud vendors are experiencing growth rates of 50% per annum.
Cloud computing exhibits the following key characteristics:
Agility improves with users' ability to re-provision technological infrastructure resources.
Application programming interface (API) accessibility to software that enables machines to interact with cloud software in the same way that a traditional user interface (e.g., a computer desktop) facilitates interaction between humans and computers. Cloud computing systems typically use Representational State Transfer (REST)-based APIs.
Cost reductions claimed by cloud providers. A public-cloud delivery model converts capital expenditure to operational expenditure. This purportedly lowers barriers to entry, as infrastructure is typically provided by a third party and does not need to be purchased for one-time or infrequent intensive computing tasks. Pricing on a utility computing basis is fine-grained, with usage-based options and fewer IT skills are required for implementation (in-house). The e-FISCAL project's state-of-the-art repository contains several articles looking into cost aspects in more detail, most of them concluding that costs savings depend on the type of activities supported and the type of infrastructure available in-house.
Device and location independence enable users to access systems using a web browser regardless of their location or what device they use (e.g., PC, mobile phone). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere.
Maintenance of cloud computing applications is easier, because they do not need to be installed on each user's computer and can be accessed from different places.
Multitenancy enables sharing of resources and costs across a large pool of users thus allowing for:
centralization of infrastructure in locations with lower costs (such as real estate, electricity, etc.)
peak-load capacity increases (users need not engineer for highest possible load-levels)
utilisation and efficiency improvements for systems that are often only 10–20% utilised.
Performance is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.
Productivity may be increased when multiple users can work on the same data simultaneously, rather than waiting for it to be saved and emailed. Time may be saved as information does not need to be re-entered when fields are matched, nor do users need to install application software upgrades to their computer.
Reliability improves with the use of multiple redundant sites, which makes well-designed cloud computing suitable for business continuity and disaster recovery.
Scalability and elasticity via dynamic ("on-demand") provisioning of resources on a fine-grained, self-service basis in near real-time (Note, the VM startup time varies by VM type, location, OS and cloud providers), without users having to engineer for peak loads.
Security can improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels. Security is often as good as or better than other traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford to tackle. However, the complexity of security is greatly increased when data is distributed over a wider area or over a greater number of devices, as well as in multi-tenant systems shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible. Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.
Platform as a service (PaaS)
Main article: Platform as a service
In the PaaS models, cloud providers deliver a computing platform, typically including operating system, programming language execution environment, database, and web server. Application developers can develop and run their software solutions on a cloud platform without the cost and complexity of buying and managing the underlying hardware and software layers. With some PaaS offers like Microsoft Azure and Google App Engine, the underlying computer and storage resources scale automatically to match application demand so that the cloud user does not have to allocate resources manually. The latter has also been proposed by an architecture aiming to facilitate real-time in cloud environments. Even more specific application types can be provided via PaaS, e.g., such as media encoding as provided by services as bitcodin transcoding cloud or media.io.
Software as a service (SaaS)
Main article: Software as a service
In the business model using software as a service (SaaS), users are provided access to application software and databases. Cloud providers manage the infrastructure and platforms that run the applications. SaaS is sometimes referred to as "on-demand software" and is usually priced on a pay-per-use basis or using a subscription fee.
In the SaaS model, cloud providers install and operate application software in the cloud and cloud users access the software from cloud clients. Cloud users do not manage the cloud infrastructure and platform where the application runs. This eliminates the need to install and run the application on the cloud user's own computers, which simplifies maintenance and support. Cloud applications are different from other applications in their scalability—which can be achieved by cloning tasks onto multiple virtual machines at run-time to meet changing work demand. Load balancers distribute the work over the set of virtual machines. This process is transparent to the cloud user, who sees only a single access point. To accommodate a large number of cloud users, cloud applications can be multitenant, that is, any machine serves more than one cloud user organization.
The pricing model for SaaS applications is typically a monthly or yearly flat fee per user, so price is scalable and adjustable if users are added or removed at any point.
Proponents claim SaaS allows a business the potential to reduce IT operational costs by outsourcing hardware and software maintenance and support to the cloud provider. This enables the business to reallocate IT operations costs away from hardware/software spending and personnel expenses, towards meeting other goals. In addition, with applications hosted centrally, updates can be released without the need for users to install new software. One drawback of SaaS is that the users' data are stored on the cloud provider's server. As a result, there could be unauthorized access to the data. For this reason, users are increasingly adopting intelligent third-party key management systems to help secure their data.
LỜI BÀI HÁT
LynhKey … PRBoiz … Thanhtien
Mah love the feel……
Ver 1: Thangzet
Chậm lại 1 chút .. chắc sẽ hay !?!!?
Em muốn như thế này … có phải không !?!?!
2012 đâu cần nhanh , ko cần twist
Ngày tận thế có đến gần …mtf ko cần biết !?
Anh chỉ biết là “ Ngày Tận Thế “ tình chúng ta
E rẽ đôi con đường , chút âm âm thầm người bước qua
Tại sao chuyện 2 chúng mình , ko thể bước qua con số 3
Hay tất cả mọi chuyện đó là , người thứ 3 đứng sau chúng ta
Em nói đi … sao cứ nhìn rồi im lặng !?!?
2 chúng mình lại như vậy !?
Khi em từng yêu anh rồi cũng đã 2 năm trời vậy mà chấm cho cái kết. Hết ! ko 1 lời ….
Bước qua 1 người như e chưa từng buông lời ….
Trái tim lạnh vậy sao !? người đàn bà đi qua đời tôi !
Những nụ hôn còn vường bờ môi . h còn lại mình tôi và tôi !
Dòng nguyệch ngoặc vô hồn mà thôi !
Biết thời gian là bao nhiu để tâm hồn này vá lại
Liều thuốc nào cho tâm trí để thôi ko còn khắc họa
Chìa khóa nào cho trái tim để tim tôi đừng khóa chặt
Và nước mắt nào trôi đi hết để ân tình này xóa sạch …
Mel: Thanhtien (thangzet)
Còn lại ji` người hãy nói đi
Những khi có chẳng còn …. Vì đời lỡ nhau bước đi phải ko !!???
Vì tình đôi lúc buồn …chẳng chung con đường
Người bên cạnh tôi …rồi âm thầm bên cạnh ai … quên r`
Ver 2: LynhKey
Chậm lại 1 chút... để nhìn vào trong quá khứ
Cuộc tình ngày đó đã theo cơn gió ...ngồi đây nói giá như..
Giá như chưa từng yêu thương..có lẽ sẽ không rơi nước mắt
Giá như chưa từng bên nhau ... thì con tim anh đã ko thắt chặt
Em ... sao bước đến rồi lại đi...
Trái tim người chia 2 ngã ... đành thôi niếu kéo để làm gì
Em chỉ đùa giỡn hay là vì..tìm tôi lắp đầy đi khoảng trống
Bao năm tình ái nay còn gì...thân xác hao gầy ngồi ngống trông
Tìm lại...tôi tìm em của ngày xưa
Người đã đi ngang qua đời tôi quên đi hết những lời hứa
Những ngày mưa ta bên nhau giờ còn đau kỹ niệm xưa
Một con đường chia ra 2 ngã thì biết hướng nào để chọn lựa
Em nói đi ... sao đứng nhìn rồi quay mặt
Những gì của ngày hôm qua biết bao giờ mới chôn chặt
Ngọn gió nào cuốn trôi hết để không còn gì vướng lại
Và tôi sẽ bước đi tiếp để không cần người thương hại
Ver 3: Thangzet
Anh chắc phải chậm thêm 1 chút …nữa vì em !
Bản thân a cần tỉnh táo để thoát …khỏi vị men !
Đôi bàn tay từng nắm , chìm vào trong tình ái
Tôi vì em từng đắm , chìm trong men say ngày ấy
Đã vào đông , anh vẫn ngủ , nhưng ko đủ được giấc
Những chuyện cũ, anh tự nhủ , mình ko giữ được thì mất
Mình cất làm ji` khi … người cứ im lặng đi !
Cứ giấu vào nơi mà người cảm thấy an toàn khi
Người quay và đi , còn mình tôi ngồi đây ,rồi lại say vì ai !?!?!?
Chắc … ai phải chậm thêm 1 chút … để em xa thật xa
Anh phải chậm cho đến khi nào … người ta bên ngta
Ngta không cần tôi , thì tôi quên ngta
Ngta đã quên dc tôi , thì tôi phái xóa đi ngta
Giữ chỉ thêm tội … phải không em !?
Chỉ cần cái beat , ít điếu thuốc …vẫn thong thả trong đêm !