"Public cloud can be used as an extension of traditional IT resources to help customers cope with changing needs"-a phrase we often say when we introduce public cloud products to our customers. Let's look at a specific requirement:
A customer has a Web site that is deployed in its own data center (on-premises), and at some unplanned peak times (assuming a promotional season), the infrastructure resources of the existing data center are not sufficient to support the burst of traffic. In this case, how does the public cloud help customers expand the processing power of their on-premises data centers to meet peak business requirements?
Well, easy, customers just have to move their existing Web sites to the public cloud, what scale-out, pay-as-you-go, redundant storage, and so on are all a bunch of "cloud features". Easily handle customer needs. Then, the customer asked the question: the application (Web site) has migrated to the public cloud, and our existing data center is not? Shut down? Idle? This is our survival of the core application, are "floating in the cloud" always feel some not practical ah ...
It seems that the original story becomes quite variable, in fact it is perfectly reasonable:
- It is unacceptable for customers to move to a public cloud and retire or idle existing infrastructure, and to do large-scale application migrations (and a range of workloads and costs around application migrations). Is it cheaper or more expensive to use cloud computing? Is it to improve work efficiency or to be more frustrating?
- Due to legal, compliance and other factors, it is impossible for customers to move all applications and data to the public cloud. But there is also a need for customers to use public clouds. For example, it is not possible for a hospital to keep all patient data and diagnostic data on the public cloud, but it can provide inspection reports/inspection results via public cloud or appointment registration services; The enterprise does not keep the financial data on the public cloud, but it can provide reconciliation, reporting, or query services through the public cloud.
- Although public clouds are much more secure and compliant than some customers ' own IT infrastructures, trust is not built in the short term. Just as we have every reason to think that it is not hundred percent safe to deposit money in a bank--what if the banks fail?
For the above problem, we can use "DNS load Balancing" to solve!
Now the DNS service is no longer silly, just to resolve the domain name to an IP address. Many providers of domain-related services have introduced intelligent DNS services. Compared with the traditional DNS resolution service, the Intelligent DNS service adds the following features:
- DNS Weight load balancing: The default DNS Load balancer is polling, that is, the DNS server distributes requests evenly to each a record. This allows for the simplest load balancing, but the user cannot control the load distribution policy. DNS Weighted load Balancing is the addition of a weight value to the default DNS load balancing mechanism, which allows users to set the number of requests distributed to each node (a record) by using a weight value to achieve "ANI"-a node with strong processing capacity that hosts some load.
- Source Intelligence Resolution: Returns the corresponding resolved value (IP address) based on the source of the customer request (location or access line). For example: The user deploys an application in China and the United States respectively, in the domain name resolution service to the same domain name set 2 different a record, corresponding to the application address of China and the United States (public network IP address). This will enable Chinese customers to deploy applications in China, where foreign clients access applications deployed in the United States, and all users use the same domain name to access the app.
At home and abroad to provide intelligent domain name resolution service vendors are: Dnspod,cloudxns, million nets, Akamai and so on. Users can also choose to use F5 's software hardware hybrid solution to build their own intelligent DNS resolution service.
The source intelligent analysis of WAN network
DNS Weight settings for dnspod
In addition to the intelligent DNS resolution services described above, Microsoft Azure and AWS also provide similar services. In Microsoft Azure, the Intelligent DNS Resolution service is Traffic Manager profile, and note that it is not traffic manager. Traffic Manager can only support apps that are deployed on Windows Azure. Traffice Manager profile can support external endpoint, i.e., DNS load balancing between Microsoft Azure and on-premises data centers, supporting performance, weight, and priority 3 load distribution algorithms.
However, there is no mainland China in the endpoint regional selection. Applications deployed in mainland China can only be selected in Southeast Asia or East Asia.
In addition, Traffic Manager profile is currently available only on the international version of Microsoft Azure, with the Chinese version of Windows Azure only traffic Manager.
On the AWS International edition, Route 53, the Intelligent DNS Resolution service, is more granular and supports the Chinese mainland (CN) than Microsoft Azure's traffic Manager profile.
With DNS load balancing, we can easily implement a hybrid cloud application deployment solution that allows customers to truly experience the benefits of the cloud.
Sincere wish: Happy New Year! 2016 cloud and leap, smooth sailing, the best luck!
Enable cross-Cloud applications-DNS-based load balancing