is container technology and server virtualization the same technology?

"Editor's note" Whether Google, Amazon, Microsoft, VMware have embraced, joined the Docker and container of the new era of cloud virtualization, these two technologies become the IT industry trends. What the hell is Docker and container? The following 9 q&a tell you.

The following is the original text:

is Q1:container technology and server virtualization the same technology?

A: No. While both are virtualization technologies, the goal is to package the execution environment required for a set of applications, to create an isolated environment that facilitates moving across different hardware, but the thinking is very different. In simple terms, common traditional virtualization technologies such as vsphere or Hyper-V are centric to the operating system, while container technology is an application-centric virtualization technology.

Traditional virtualization technology starts at the operating system level, with the goal of creating a sandbox independent execution environment that can be used to perform a whole set of operating systems, and is accustomed to addressing virtual machines (Machine). While container technology is directly to the application of the relevant program code, function library, environment configuration files are packaged to create a sandbox execution environment, in order to and traditional virtualization technology generated by the virtual machine, container technology generated by the environment is called container.

Q2: What is the difference between common virtual machines and container?

A: The most obvious difference is that the virtual machine needs to install the operating system (the guest OS installed) to execute the application, while the container does not need to install the operating system to execute the application. Instead of creating a virtual environment outside the OS, container technology creates a virtual execution environment within the core system layer of the OS, replacing the function of one guest OS by sharing the host OS. Container is also called the virtualization technology of the OS layer.

Q3: Why container is lightweight virtualization technology?

A: Because the container technology takes the shared host OS rather than executing the guest OS within each container, establishing container does not need to wait for the operating system to boot time and can be enabled in 1 minutes or seconds. It's much faster than a traditional virtual machine that takes a few minutes or even 10 minutes to open.

is Q4:container technology a new technology?

A: No, as early as 1982, the chroot mechanism built in Unix system is also a container technology. Other such as the 1998-year FreeBSD jails, the Solaris zones and OpenVZ that emerged in 2005, or the Sandboxie mechanism, like the 2004-year Windows system, is the practice of creating an isolated virtual execution environment within the operating system, Can be called container technology.

It was not until 2013 that DotCloud, the PAAs service company, released a set of container standardized platform Docker, which was popular, so DotCloud decided to set up a new company with Docker as its name.

Q5:docker How to achieve container standardization?

A:docker adopts Aufs file system to design a container image file that can layer stack, and packages all the programs in container (including application, related function library, configuration file) into Docker image files, A dockerfile configuration file is provided to record each step of the container process including parameters. As long as in any environment that supports the Docker platform, you can create an identical container from this image file to execute the same application. In this way, the application is able to move the execution environment of the program to any supporting Docker environment, either through the Docker image file or even just dockerfile. Docker also releases APIs that can be used to control all container-related directives, and anyone who uses the same set of Docker equals the same set of methods of managing and establishing container, which is equivalent to standardizing the use of container.

Q6: How many applications can be installed in a container image file?

A: Multiple programs can be installed in a container image file, such as Ubuntu, Apache, MySQL, Node.js, Ruby, and so on. However, Docker official suggested that a program be installed in a container, and then the container overlapped to provide a complete service.

Docker called it a microservices (micro-service) new software architecture that would form every stack of an application system, split into many small services such as Apache services, MySQL services, node.js services, Ruby Services, Each service is a program that is wrapped in container, such as MySQL service, which is deployed in container.

The advantage of this is that you can build a loosely coupled flexible application architecture, and easily accessible one of the container, such as upgrading MySQL, just reload the new version of MySQL's container image file, you can complete the database upgrade, do not have the entire application system downtime.

Q7:container not need OS, why do you need OS base image file?

The A:os base image file is intended to allow container to have the OS filesystem, such as using the Ubuntu base image file to allow container to establish the Ubuntu root architecture instead of executing an OS execution instance.

How does Q8:docker help DevOps?

A: Because Docker through the Dockerfile to record the creation of container image files of each step, you can establish the application execution environment of the process and configuration parameters, fully recorded. Dockerfile can be used to communicate the discussion of the execution environment between the developer and the transport personnel. Even with version control services such as GitHub, Dockerfile has versioning capabilities that can be managed by the infrastructure Program (infrastructure as code).

Q9: Can you perform docker in a windowsserver environment?

A: Not yet. Currently Docker can only be performed on Linux platforms, but Microsoft announced in October that it would build a Docker engine in the next wave of Windows Server revisions, and that the future of the same Docker image could span Linux and Windows OS, You need to wait until Microsoft exposes more details.

Original link: 10 Q&a quick know Docker (Zebian/Wei)

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