What is the difference between docker, kvm, and xen virtualization?

The difference between docker, kvm, and xen virtualization: 1. Docker saves more resources than kvm and can provide performance very close to the host. However, kvm resource isolation is higher than docker, and kvm supports more types of operating systems. More; 2. Docker is containerization and can be started in seconds, which is much faster than kvm and xen virtualization.

The operating environment of this tutorial: linux7.3 system, docker version 19.03, Dell G3 computer.

What is the difference between docker and kvm and xen virtualization?

Summary summary:

docker saves resources than kvm and can provide very close The performance of the host machine, while kvm resource isolation is higher than docker, kvm supports more operating system types

In terms of applications, docker (can withstand tossing, fast deployment), in terms of systems, kvm (host isolation , also supports snapshots)

Separate explanation type:

Docker is containerization, startup can be achieved in seconds, much faster than traditional virtual machines, Docker is The utilization rate of system resources is very high. Thousands of Docker containers can be run simultaneously on one host.

Advantages:

Efficiently utilize system resources

Fast startup time

Consistent running environment

Continuous delivery and deployment

Easier maintenance and expansion

KVM is an open source system virtualization The virtualization module uses liunx's own scheduler management. After using kvm to virtualize multiple physical machines, they form a large virtualized resource pool, which facilitates users to allocate computing power from the resource pool and improve resource usage efficiency. Ensure isolation and security between multi-user resources

Knowledge Expansion

As an emerging virtualization method, Docker has many advantages over traditional virtualization methods.

1. Docker containers can be started in seconds, which is much faster than the traditional virtual machine method. Secondly, Docker has a high utilization rate of system resources. Thousands of Docker containers can be run simultaneously on one host.

2. In addition to running the application in it, the container basically consumes no additional system resources, making the application performance very high and the system overhead as small as possible. The traditional virtual machine method requires 10 virtual machines to run 10 different applications, while Docker only needs to start 10 isolated applications.

3. Virtualization technology relies on physical CPU and memory and is at the hardware level; while docker is built on the operating system and utilizes the containerization technology of the operating system, so docker can even run on a virtual machine.

4. Virtualization systems generally refer to operating system images, which are relatively complex and are called "systems"; while docker is open source and lightweight and is called "containers". A single container is suitable for deploying a small number of applications, such as A redis, a memcached.

5. Traditional virtualization technology uses snapshots to save state; docker is not only more portable and low-cost in saving state, but also introduces a similar source code management mechanism to store the snapshot historical versions of the container one by one. Records, switching costs are low.

6. Traditional virtualization technology is more complex when building the system and requires a lot of manpower; while docker can build the entire container through Dockfile, and restart and build quickly. More importantly, the Dockfile can be written manually, so that application developers can guide the system environment and dependencies by publishing the Dockfile, which is very beneficial to continuous delivery.

7. Of course, KVM also has a big advantage over containers, which is that it can use different operating systems or kernels. So, for example, you could use Microsoft Azure and run an instance of Windows Server 2012 and an instance of SUSE Linux Enterprise Server simultaneously. As for Docker, all containers must use the same operating system and kernel.

Recommended learning: "docker video tutorial"

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