Shulou(Shulou.com)06/02 Report--

Under what circumstances should we consider making some changes?

The traditional business is suddenly impacted by the Internet business, the application is always changing, it needs to be updated every three days, and the traffic has increased. The original payment system is to withdraw money and swipe the card, but now it is necessary to pay on the Internet, and the traffic has expanded N times.

No way, one word: dismantle

Apart, each sub-module changes independently and has less influence on each other.

Taken apart, one process used to carry the traffic, but now multiple processes carry it together.

So it's called micro-service.

In the micro-service scenario, there are many processes and updates are fast, so there are 100 processes and one mirror every day.

The container is happy, the mirror image of each container is small, there is no problem, and the virtual machine cries because each image of the virtual machine is too big.

So in the micro-service scenario, you can start to consider using containers.

Virtual machine angry, I do not use containers, after the micro-service split, using Ansible automatic deployment is the same.

There is no problem from a technical point of view.

However, the problem arises from an organizational point of view.

In ordinary companies, there are many more developers than OPS. You don't have to worry about the development after writing the code. The deployment of the environment is entirely the responsibility of OPS. For automation, OPS writes Ansible scripts to solve problems.

However, there are so many processes, dismantled and merged, updated so quickly, the configuration is always changing, and the Ansible script has to be changed every day, so that the operation and maintenance staff must not be exhausted.

So with such a large workload, it is easy for operators to make mistakes, even through automated scripts.

At this point, the container can be used as a very good tool.

In addition to the fact that the container, from a technical point of view, enables most of the internal configuration to be placed in the image, more importantly, from the process point of view, the environment configuration has been pushed forward to the development here, requiring that after the development is completed, you need to consider the deployment of the environment, rather than being a shopkeeper.

The advantage of this is that although there are many processes, many configuration changes, and frequent updates, this amount is very small for the development team of a module, because 5-10 individuals specialize in maintaining the configuration and updates of the module and are not prone to errors.

If all this workload is handed over to a small number of operation and maintenance teams, not only the transmission of information will make the configuration of the environment inconsistent, but also the amount of deployment will be much larger.

Container is a very good tool, that is, if each developer does only 5% more work, it can save 200% of the work of operation and maintenance, and is not prone to error.

However, the original operation and maintenance should have done the development of things, the development of the boss is willing? Does the developer complain against the boss of operation and maintenance?

This is not a technical problem, in fact, DevOps,DevOps does not distinguish between development and operation and maintenance, but the company can get through from the organization to the process to see how to cooperate and how to demarcate the boundaries, which is more beneficial to the stability of the system.

So microservices, DevOps and containers are complementary and inseparable.

It is not a micro service, it does not need a container at all, a virtual machine can handle it, it does not need DevOps, it can be deployed once a year, and no matter how slow the communication between developers and OPS is.

Therefore, the essence of containers is cross-environment migration based on mirrors.

Mirroring is the fundamental invention of containers and the standard for encapsulation and operation. Other namespace,cgroup has existed for a long time. This is a technical aspect.

In terms of process, mirroring is a good tool for DevOps.

Containers are designed to migrate across environments, and the first migration scenario is between development, test, and production environments. If you don't need to migrate, or if you don't migrate frequently, virtual machine images are fine, but you always have to migrate, with hundreds of gigabytes of virtual machine images, which is too big.

The second migration scenario is that the migration of virtual machines across clouds, public clouds, Region and two OpenStack is very troublesome, even impossible, because the public cloud does not provide downloading and uploading of virtual machine images, and the virtual machine images are so large that they are uploaded one day at a time.

Therefore, containers are also a good use scenario in cross-cloud scenarios and hybrid cloud scenarios. At the same time, it also solves the problem that only private cloud resources are insufficient to carry traffic.

Scenarios for the correct use of containers:

Based on the above analysis, we find that containers are recommended for use in the following scenarios.

1. Deploy stateless services for complementary use with virtual machines for isolation

two。 If you want to deploy stateful services, you need to know a lot about the applications in it.

3. As an important tool of continuous integration, it can migrate smoothly between development, testing and production.

4. Suitable for deployment and auto scaling of applications in cross-cloud, cross-Region, cross-data center, hybrid cloud scenarios

5. Use the container as the deliverable of the application, maintain environmental consistency and establish the concept of unchangeable infrastructure.

6. A program that runs the basic task types of a process

7. Used to manage changes, applications that change frequently use container images and version numbers, which are much more lightweight and convenient

8. Be sure to manage the application and design health check and fault tolerance when using the container.

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