cloud computing note(2)
Cloud computing can be deployed in four main ways:
- Public: infrastructure and services offered to many customers, and managed by third-party vendor. We have to share with others security issues, so only thing we can do is to trust the provider. The benefit is cheap and you pay as you use.
- Private: an organization has their own infrastructure and services locally or on the cloud managed by the organization or third party. Although it will spend more money and time and also need expertise to configure, maintain and administe, the benefit is easier to make sure security standards, policies and other things.
- Community: share resources with someone you know, these organizations have similar needs which means they are in a specific business sector and they can pay money together. These resources will be managed by organizations or third party.
- Hybrid: mixture of two or more cloud models.
Public cloud: multi-tenancy: a computer could host virtual machines for multiple organizations.
Private cloud: single-tenant: services offered to a single customer.
Two types of private cloud:
- on-premises: the data center is located in the organization locally and managed by the organization or third party.
- hosted: the data center is provided from third-party vender and managed by third party.
How about the security of these different clouds?
This is a difficult question and depends on different situations. We cannot say that the private cloud must be safer than public cloud. And also we cannot say that a on-premises private cloud is safer than a hosted private cloud.
For example, if we have a small company, and if we want to have a private cloud, maybe the on-premises cloud is better because we don’t have enough fund and resources to maintain servers, networks and storage locally. Maybe for a small company, the public cloud is better than other cloud. If we have a big company, the hosted private cloud is a good choice because we have enough resources and good expertise to configure and manage our resources and we can do it as we needs.
Cloud Computing has a lot of benefits and we can categorize for two aspects:
- technical: technical benefits are evolutionary because we just integrate a number of existing technologies.
- business: business benefits are revolutionary because we change the way that we did IT as a resource.
For SaaS: we have large choices of software from different venders and we don’t need to configure and think about how to update.
For PaaS: the tasks of administration and maintenance reduced. When we do a project, we always work locally, each pc is different. And now we do it for a safe VM environment. If the application is bigger, the platform will grow bigger.
For IaaS: your price follow what you need and if we use more servers, we just need to pay for it.
We save more money because of Pay-as-you-use model and the decreasing administration costs. It is easier to share information and collaborate, for example, SharePoint or Exchange.
When we use VM, our VM will create a guest operating system for itself. And if we use docker, all the containers in a docker are shared the same operating system and kernel.
Containers are faster and lightweight, and VMs have better isolation and security control.
We can install docker in different operating systems, like Windows, Mac and Linux.
Without swarm, we manage containers. With swarm, we manage services.
We have different nodes: managed node and worker node. The managed node is manager for worker nodes. Each node will have global services. When managed node configure that we have three worker nodes to start the replicated service, the worker node will start this service.
Compose is a tool for defining and running multi-container Docker applications