Shulou(Shulou.com)06/03 Report--

Today's editor brings you an article introducing OpenStack knowledge points. Xiao Bian thinks it is quite practical, so share it for everyone to make a reference. Let's follow the editor and have a look.

1. Parallel computing

Parallel computation, or parallel computation, is a computer algorithm as opposed to serial computation.

Parallel computing refers to the process of solving a computational problem using multiple computing resources simultaneously, thereby improving the computing speed and processing power of a computer system; the basic idea of the algorithm is to decompose the problem into multiple parts, and then each part is processed by an independent processor.

2. Decoupling and coupling degree

Decoupling is an idea, but also one of the methods of dealing with complex transactions, generally mentioned in the development of programs and architectural design. For example, developers generally need to write multiple functions when developing a project, each function may have a certain connection with other functions directly, if these function codes are written in a file, on the one hand, the file length is too long, and it is inconvenient to name, on the other hand, it is difficult to locate and maintain when problems occur in the later stage. Therefore, most of the complex application development will be these functional modules of the code for multi-file writing, so that both complementary interference with internal code, but also can be related to each other. The same is true of architecture design, which talks about a complex architecture for diversified multi-module subdivision, layer-by-layer design and layout. This approach or idea is called decoupling.

Layered and distributed (systems)

Speaking of distributed systems, it happened that two days ago someone asked whether layering and distribution were similar. In fact, this problem does not need to understand the meaning of these two words to know that they are not a concept at all. Layering is an idea, a computer algorithm, and distribution is architecture-level knowledge.

Layering. We can go back to when we first learned about computer networks, and we compared the organizational structure of the company to a seven-layer model of computer networks, with each layer performing its own role. And this layered approach is layered thinking.

Distributed, generally we see more distributed computing systems and distributed storage systems. Distributed computing is the sharing of information between two or more software, which can run on the same computer or on multiple computers connected through a network; distributed systems are generally used in systems such as network storage, and specific applications are to store data on multiple independent devices to meet data security, reliability, and improve system performance. Of course, distributed systems also have their own shortcomings, such as the need for monitoring, unified control, performance is very dependent on the network and resource allocation strategy. You can think about it yourself or consult relevant information.

4、RESTful

REST is a web application design style and development approach, but it does not have clear standards, RESTful is an application or design that meets REST-related conditions or principles.

In OpenStack, RESTful APIs represent applications called by OpenStack services, or interfaces. If you still don't understand it, you can understand it as a function called by network resources (it's not difficult to understand if you have learned a little programming).

5. Virtualization

Virtualization refers to virtualizing a computer into multiple logical computers through virtualization technology. For example, we install VMware on our Windows host machine (local computer) and then create various virtual machine instances in the software, such as Linux operating system virtual machines such as Centos, SUSE, Ubuntu, etc., or Windows system virtual machines such as Windows 10.

Virtualization uses software to redefine the division of IT resources, which can realize dynamic allocation, flexible scheduling and cross-domain sharing of IT resources, improve IT resource utilization, and enable IT resources to truly become social infrastructure to serve flexible and changeable application needs in various industries.

Message Queue and AMQP

Message Queue--Message Queue, look at this English you will find and AMQP in the middle of the two letters consistent, yes, AMQP MQ also means message queue. Below we will briefly discuss the definitions and differences between the two.

Let's talk about AMQP first. It is written as Advanced Message Queuing Protocol. You may understand it when you see it here. This is a protocol. It is translated into Advanced Message Queue Protocol in Chinese. The protocol is an application layer standard Advanced Message Queue Protocol that provides unified messaging services. It is an open standard for application layer protocols and is designed for message-oriented middleware.

The client and messaging middleware based on this protocol can transfer messages, and are not limited by different client/middleware products and different development languages. For example, RabbitMQ, developed by Erlang, etc.

Message queues, however, are just a conceptual introduction and do not go into detail about the theoretical knowledge of producers and consumers. Message queue, which can be considered as the message middleware in the above, is mainly used to place data in the queue when transmitting data, as shown in the following figure:

Among them, the role of enqueuing (putting data into queue) on the left is called producer, while the role of dequeuing (taking data out of queue) is called consumer, which can also be understood from the biological level.

Message queues (messaging middleware) also play an important role in OpenStack.

7. Heat migration

Hot migration is a method of data migration relative to cold migration.

Cold migration, we are for virtual machines, the directory where the virtual machine disk is stored is generally mounted on a disk with an nsf file system, and this disk is usually an LVM file system (see the Linux operating system for disk management). From this, we can do a datastore migration by shutting down the virtual machine, i.e. with cold migration, we have the option to move the associated disks from one datastore to another. The advantage is that data is not easily lost, and the disadvantage is that it requires downtime for operation. Cold migration is also called static migration.

Hot migration is to save the entire running state completely, and at the same time, it can be quickly restored to the original hardware platform or even migrated to different hardware platforms. After recovery, it works normally, and users will not notice a change in service during migration, that is, hot migration does not require server downtime. Therefore, thermal migration is also called dynamic migration or live migration.

Supplement: The above specific disk management can refer to the author's previous article, the following are mainly related to LVM related knowledge of the two articles:

Disk Management and File Systems for Linux System Administration

2.Linux disk management LVM logical volume understanding and management details

8、VNC

VNC-Virtual Network Console stands for Virtual Network Console. is a remote control tool software, is based on UNIX and Linux operating system free open source software, used to provide remote connection computer, such as VMRC, SSH, Telnet, RAS and so on.

The above is the detailed content of OpenStack knowledge points. Is there any gain after reading it? If you want to know more about it, welcome to pay attention to industry information!

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