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A brief introduction to Docker-Compose

Compose is a tool for defining and running container docker applications. With Compose, you can use YAML files to match all the services your application needs. Then, with a single command, you can create and start all services from the YAML file fit. Then you need to understand the basic syntax of YAML files.

Basic syntax for YAML files:

Case-sensitive; use indentation to indicate hierarchical relationships; indentation does not allow tab, only spaces; the number of indented spaces is not important, as long as elements of the same level are left-aligned; "#" indicates comments

Docker-Compose is a container orchestration tool. Through a .yml or .yaml file, write all container deployment methods, file mappings, container port mappings, and so on in a configuration file, and execute the docker-compose up command just like executing a script to install and deploy the container one by one.

Dockerfile allows users to manage a separate application container, while Compose allows users to define a set of associated application containers in a template (YAML format)

Docker Compose divides the managed container into three layers:

Engineering (project); service (service); container (container)

All the yml files under the docker compose running directory form a project, and a project contains multiple services, each of which defines the images, parameters and dependencies of the container. A service can include multiple container instances.

Docker-compose is the orchestration tool for docker containers, which mainly deals with the management of multiple containers that depend on each other.

II. Installation and use of docker-compose tools

If you want to use docker-comppose as a container orchestration tool, the host must be a docker-based environment, and you can refer to the detailed installation tutorial of docker. After the docker environment is solved, download the command docker-compose, which can be downloaded on the official website of GitHub, as shown below:

When downloading the compose tool, you need to check the local docker version first!

[root@docker ~] # docker-v / / View the version information of docker Docker version 18.09.0, and build 4d60db4// version 18.9.0 this time

If the docker version is too low, you can find other versions of the docker-compose tool yourself. After selecting the appropriate version, execute the commands found on the github website.

[root@docker ~] # curl-L https://github.com/docker/compose/releases/download/1.25.0/docker-compose-`uname-s`-`uname-m`-o / usr/local/bin/docker-compose [root@docker ~] # chmod + x / usr/local/bin/docker-compose

If the network speed is not good, you can use the following command:

[root@docker ~] # curl-L https://get.daocloud.io/docker/compose/releases/download/1.25.0/docker-compose-`uname-s`-`uname-m` > / usr/local/bin/docker-compose [root@docker ~] # chmod + x / usr/local/bin/docker-compose// use Daoyun's accelerator to download [root@docker ~] # docker-compose-v / / View the version information of the tool docker-compose version 1.25.0 Build 0a186604 3. Write .yml file (1) build a simple Nginx service. Yyml file [root@docker ~] # vim / root/.vimrc set tabstop=2 [root@docker ~] # source / root/.vimrc// due to the heavy use of the tab key So set in advance the number of spaces represented by the tab key [root@docker ~] # mkdir compose_ test [root @ docker ~] # cd compose_test/ to create a test directory Used to store docker-compose.yml files / / it is recommended that there is only one docker-compose.yml file in a directory [root@docker compose_test] # vim docker-compose.yml / / write a docker-compose.yml file version: "3" / / version of the specified syntax services: / / define service nginx: container _ name: web_nginx / / the name of the container running image: nginx / / the image restart: always / / used to start ports:-90:80 / / mapped port when the docker service is started Volumes:-/ root/compose_test/webserver:/usr/share/nginx/html / / Local and container mounted directories / / write files note indentation [root@docker compose_test] # docker-compose up-d bind / generate the corresponding container / / "- d" option using the docker-compose.yml file in the current directory It means running in the background. If it is not specified, it will run in the foreground by default, which will occupy the terminal [root@docker compose_test] # docker ps / / view the container CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMESc674041cc65b nginx "nginx-g 'daemon of …" 8 minutes ago Up 8 minutes 0.0.0.0 80/tcp web_ 90-> 80/tcp web_ nginx [root @ docker compose_test] # echo "hello world" > webserver/index.html// create a test page [root@docker compose_test] # curl 127.0.0.1:90hello world// access test [root@docker compose_test] # docker-compose stop / / stop the container specified in the file [root] through the .yml file @ docker compose_test] # docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES// View effect [root@docker ~] # docker-compose-f / root/compose_test/docker-compose.yml up-dash / you can use the "- f" option to specify the container defined in the yml file startup file (2) compose+dockerfile build image [root@localhost ~] # mkdir compose & & cd compose / / create a test directory and enter [root@localhost compose] # vim Dockerfile / / create dockerfileFROM nginx:latestADD html / usr/share/nginx/html [root@localhost compose] # vim docker-compose.yml / / write the yml file version: "3" services: nginx: build:. / / specify the path to dockerfile here Can write relative path or absolute path container_name: mynginx / / generated container name image: mynginx / / use the image name generated by dockerfile restart: always ports:-70:80 [root@localhost compose] # mkdir html [root@localhost compose] # echo "hello world" > html/index.html / / To create a web page directory [root@localhost compose] # docker-compose build / / is to generate a dockerfile file into an image [root@localhost compose] # docker-compose up-d / / directly generate a container The previous command can ignore [root@localhost compose] # curl 127.0.0.1:70hello world// test effect (3) use .yml file to build a blog platform [root@localhost ~] # mkdir wordpress & & cd wordpress / / create a test directory [root@localhost wordpress] # vim docker-compose.yml / / write the yml file version: "3.1" services: wordprss: image: wordpress / / specify the image restart: always ports:-8080 environment: / / specify the mapped port environment: / / modify the environment variable WORDPRESS_DB_HOST: db WORDPRESS_DB_USER inside the container: Wordpress WORDPRESS_DB_PASSWORD: 123.com WORDPRESS_DB_NAME: wordpress db: image: mysql:5.7 restart: always environment: MYSQL_DATABASE: wordpress MYSQL_USER: wordpress MYSQL_PASSWORD: 123.com MYSQL_ROOT_PASSWORD: 123.com [root@localhost wordpress] # docker-compose up-d / / generate the appropriate container And run [root@localhost wordpress] # netstat-anpt in the background | grep 8080 / / make sure the port is listening tcp6 0 0:: 8080: * LISTEN 5546/docker-proxy [root@localhost wordpress] # docker ps | grep word / / make sure the container is running 81dd5fe032a6 wordpress "docker-entrypoint.s …" 7 minutes ago Up 7 minutes 0.0.0.0 80/tcp wordpress_wordprss_1702b530d7679 mysql:5.7 8080-> 80/tcp wordpress_wordprss_1702b530d7679 mysql:5.7 "docker-entrypoint.s …" 7 minutes ago Up 7 minutes 3306/tcp, 33060/tcp wordpress_db_1 [root@localhost wordpress] # echo "net.ipv4.ip_forward = 1" > > / etc/sysctl.conf [root@localhost wordpress] # sysctl-pnet.ipv4.ip_forward = 1

You can now access the test page. As shown in the figure:

Visit the blog you set up successfully!

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