* In those days, when all programs were written in assembler, the programs were distributed by mail, users had already installed and tested them, because testing in the companies was not provided. In case of problems, the user informed the developer about the problems to the company and, after fixing them, received by mail the already corrected version on the disk. The process is very long and the user tested it himself.

* During the distribution on disks, companies already wrote their software products in higher-level languages, tested them for different OS versions. Hereinafter, we will consider free software. The program already contained a MakeFile, which itself compiled and installed the program.

* Since the advent of the Internet, software is massively installed using package managers, when they exit, it is downloaded and installed from the remote OS repository. He tries to monitor and maintain the compatibility of the compatibility of programs. Further study and use of the program: how to start it, how to configure it, how to understand that it works falls on the user or the system administrator.

* With the advent of Docker Hub and WEB, applications are downloaded and run by a container. It usually does not need to be configured for initial operation.

For containers and images in general, the server can adjust the amount of free space and the occupied space. By default, 10G is allocated for all containers and images, while this volume should remain as dm.min_free_space = 5%, but it is better to put it in the config, which may have to be created as /etc/docker/daemon.json :

{

"storage-opts": [

"dm.basesize = 50G",

"dm.min_free_space = 5%",

]

}

You can limit the resources consumed by the container in its settings:

* -m 256m – maximum size of RAM consumption (here 256Mb);

* -c 512 – CPU usage priority weight (1024 by default);

* —Cpuset = "0,1" – numbers of allowed processor cores.

Product transfer and distribution

To transfer a project, for example, to a customer, and distribute it between developers and servers, you can use installation scripts, archives, images, and containers. Each of these ways to distribute a project has its own characteristics, disadvantages and advantages. Let's talk about them and compare.

lines, but the main thing is that it has a special mode, enabled by the -p switch , which dynamically outputs the number of lines we need, when new ones arrive, it updates the output, for example, docker logs name_container | tail -p .

When there are too many applications to manually monitor their work separately, it is advisable to centralize application logs. For centralization, numerous programs can be used that collect logs from different services and send them to a central repository, for example, Fluentd. It is convenient to use ElasticSearch to store logs, simply by writing them to a search engine. It is highly desirable that the logs are in a structured format – JSON. This will allow you to sort them, select the ones you need, identify trends using built-in aggregate functions, perform analysis and forecasting, and not just search by text. For analysis, the Kubana web interface included in the Elastic stack.

Logging is important not only for long-running applications. So for test containers, it is convenient to get the output of the passed dough. This can be done by writing in the Dockerfile in the CMD section: NPM run, which will run the tests.

Image storage:

* public and private Docker Hub (http://hub.docker.com)

* for private and secret projects, you can create your own image repository. The image is called registry