Manually Deploying Docker

Introduction

This section describes how to manually deploy Docker on a Linux FlexusL instance on Huawei Cloud, and provides common Docker operations and a simple image creation process.

This section uses CentOS 7.5 64bit (40 GiB), Debian 12.0.0 64bit, and Ubuntu 22.04 as examples. Docker requires a 64-bit OS with a kernel version of 3.10 or later.

Prerequisites

• You have purchased a FlexusL instance and the instance is in the running state.
• The security group rules listed in the following table have been added to the security groups that the FlexusL instance belongs to. For details, see Configuring Security Group Rules for a FlexusL Instance.

  Table 2 Security group rules

  Direction	Priority	Action	Type	Protocol & Port	Source
  Inbound	1	Allow	IPv4	TCP: 80	0.0.0.0/0

Deploying Docker

Perform the following operations based on the OS.

Basic Operations on Docker

1. Manage Docker processes.
   • Start Docker.

     systemctl start docker

   • Stop Docker.

     systemctl stop docker

   • Restart Docker.

     systemctl restart docker

2. Manage images.
   1. Pull docker images. The official Apache and CentOS images are used as an example.

      docker pull httpd

      docker pull centos

   2. View existing images.

      docker images

      

   3. Forcibly delete an image.

      docker rmi centos

3. Manage containers.
   1. Create a container and run it.

      docker run -it -d -p 80:80 --name datahttpd -v /data/:/var/www/httpd/ httpd

      The parameters are as follows:

      • -i: runs the container in interactive mode, which is usually used with -t.
      • -t: reallocates a pseudo input terminal to the container. This parameter is usually used with -i.
      • -d: runs the container at the backend and returns the container ID.
      • -p: maps ports, in the format of "Host port:Container port".
      • --name: specifies a name for the container.
      • -v: mounts an absolute directory on the host to the image, in the format of "Directory on the host:Mount path in the image".
      

      In the parameters, the host refers to the target ECS.

      In this example, a container is created and run from the httpd image in interactive mode. Port 80 of the container is mapped to port 80 of the host. The /data directory of the host is mapped to the /var/www/httpd directory of the container. The container ID will be returned.

      

   2. Check whether the container has been started.

      docker ps -a

      

   3. Enter the EIP of the FlexusL instance in the address bar of the browser and check the container running status. If the following information is displayed, the container is running properly.

      

Creating an Image

Use Dockerfile to customize a simple Nginx image.

1. Create a file named Dockerfile.

   mkdir mynginx

   cd mynginx

   touch Dockerfile

2. Edit Dockerfile.

   vim Dockerfile

   Add the following data to the file:

   FROM nginx
   RUN echo '<h1>Hello, Docker!</h1>' > /usr/share/nginx/html/index.html

   Simple Dockerfile commands are as follows (for more information, log in at https://docs.docker.com):

   • FROM statement (mandatory): must be the first instruction in Dockerfile, indicating that the Nginx image is used as a basic image.
   • RUN statement: indicates that the echo command is executed with the message "Hello, Docker!" displayed on the screen.
3. Build the image.

   docker build -t nginx:v3 .

   • -t nginx:v3: specifies the image name and version.
   • .: specifies the context path. After the image-built command is executed, all data in the path will be packed to the Docker engine to build the image.
4. Check the created Nginx image, the version of which is v3.

   docker images