介绍 (Introduction)

Docker is an application that simplifies the process of managing application processes in containers. Containers let you run your applications in resource-isolated processes. They’re similar to virtual machines, but containers are more portable, more resource-friendly, and more dependent on the host operating system.

Docker是一种应用程序，可简化容器中管理应用程序流程的过程。 容器使您可以在资源隔离的进程中运行应用程序。 它们类似于虚拟机，但是容器更可移植，更资源友好并且更依赖于主机操作系统。

For a detailed introduction to the different components of a Docker container, check out The Docker Ecosystem: An Introduction to Common Components.

有关Docker容器的不同组件的详细介绍，请查看Docker生态系统：通用组件简介 。

In this tutorial, you’ll install and use Docker Community Edition (CE) on Ubuntu 20.04. You’ll install Docker itself, work with containers and images, and push an image to a Docker Repository.

在本教程中，您将在Ubuntu 20.04上安装和使用Docker Community Edition(CE)。 您将安装Docker本身，使用容器和映像，然后将映像推送到Docker存储库。

先决条件 (Prerequisites)

To follow this tutorial, you will need the following:

要遵循本教程，您将需要以下内容：

• One Ubuntu 20.04 server set up by following the Ubuntu 20.04 initial server setup guide, including a sudo non-root user and a firewall.

  按照Ubuntu 20.04初始服务器设置指南设置一台Ubuntu 20.04服务器，包括sudo非root用户和防火墙。

• An account on Docker Hub if you wish to create your own images and push them to Docker Hub, as shown in Steps 7 and 8.

  如果要创建自己的映像并将其推送到Docker Hub，请在Docker Hub上创建一个帐户，如步骤7和8所示。

第1步-安装Docker (Step 1 — Installing Docker)

The Docker installation package available in the official Ubuntu repository may not be the latest version. To ensure we get the latest version, we’ll install Docker from the official Docker repository. To do that, we’ll add a new package source, add the GPG key from Docker to ensure the downloads are valid, and then install the package.

官方Ubuntu存储库中提供的Docker安装软件包可能不是最新版本。 为确保获得最新版本，我们将从官方Docker存储库中安装Docker。 为此，我们将添加一个新的软件包源，从Docker添加GPG密钥以确保下载有效，然后安装该软件包。

First, update your existing list of packages:

首先，更新您现有的软件包列表：

Next, install a few prerequisite packages which let apt use packages over HTTPS:

接下来安装这让一些必备软件包apt使用的包装通过HTTPS：

Then add the GPG key for the official Docker repository to your system:

然后将官方Docker存储库的GPG密钥添加到您的系统中：

Add the Docker repository to APT sources:

将Docker存储库添加到APT源：

Next, update the package database with the Docker packages from the newly added repo:

接下来，使用新添加的存储库中的Docker软件包更新软件包数据库：

Make sure you are about to install from the Docker repo instead of the default Ubuntu repo:

确保要从Docker存储库而不是默认的Ubuntu存储库进行安装：

You’ll see output like this, although the version number for Docker may be different:

您将看到这样的输出，尽管Docker的版本号可能不同：

docker-ce:
  Installed: (none)
  Candidate: 5:19.03.9~3-0~ubuntu-focal
  Version table:
     5:19.03.9~3-0~ubuntu-focal 500
        500 https://download.docker.com/linux/ubuntu focal/stable amd64 Packages

Notice that docker-ce is not installed, but the candidate for installation is from the Docker repository for Ubuntu 20.04 (focal).

请注意，尚未安装docker-ce ，但安装的候选人来自Ubuntu 20.04的Docker信息库( focal )。

Finally, install Docker:

最后，安装Docker：

Docker should now be installed, the daemon started, and the process enabled to start on boot. Check that it’s running:

现在应该安装Docker，启动守护程序，并启用启动过程。 检查它是否正在运行：

The output should be similar to the following, showing that the service is active and running:

输出应类似于以下内容，表明该服务处于活动状态并且正在运行：

   
   

    
    Output
   
   
● docker.service - Docker Application Container Engine
     Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2020-05-19 17:00:41 UTC; 17s ago
TriggeredBy: ● docker.socket
       Docs: https://docs.docker.com
   Main PID: 24321 (dockerd)
      Tasks: 8
     Memory: 46.4M
     CGroup: /system.slice/docker.service
             └─24321 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Installing Docker now gives you not just the Docker service (daemon) but also the docker command line utility, or the Docker client. We’ll explore how to use the docker command later in this tutorial.

现在，安装Docker不仅可以为您提供Docker服务(守护程序)，还可以为您提供docker命令行实用程序或Docker客户端。 在本教程的后面，我们将探讨如何使用docker命令。

步骤2 —在不使用Sudo的情况下执行Docker命令(可选) (Step 2 — Executing the Docker Command Without Sudo (Optional))

By default, the docker command can only be run the root user or by a user in the docker group, which is automatically created during Docker’s installation process. If you attempt to run the docker command without prefixing it with sudo or without being in the docker group, you’ll get an output like this:

默认情况下，只能以root用户或由docker组中的用户运行docker命令，而docker组是在Docker安装过程中自动创建的。 如果您尝试运行docker命令而不以sudo作为前缀或不在docker组中，则将获得以下输出：

   
   

    
    Output
   
   
docker: Cannot connect to the Docker daemon. Is the docker daemon running on this host?.
See 'docker run --help'.

If you want to avoid typing sudo whenever you run the docker command, add your username to the docker group:

如果要避免在每次运行docker命令时键入sudo ，请将用户名添加到docker组：

To apply the new group membership, log out of the server and back in, or type the following:

要应用新的组成员身份，请注销服务器并重新登录，或键入以下命令：

You will be prompted to enter your user’s password to continue.

系统将提示您输入用户密码以继续。

Confirm that your user is now added to the docker group by typing:

通过输入以下命令确认您的用户已添加到docker组：

   
   

    
    Output
   
   
sammy sudo docker

If you need to add a user to the docker group that you’re not logged in as, declare that username explicitly using:

如果需要将用户以未登录的身份添加到docker组中，请使用以下命令明确声明该用户名：

The rest of this article assumes you are running the docker command as a user in the docker group. If you choose not to, please prepend the commands with sudo.

本文的其余部分假设您以docker组中的用户身份运行docker命令。 如果您选择不这样做，请在命令前加上sudo 。

Let’s explore the docker command next.

接下来让我们探索docker命令。

第3步—使用Docker命令 (Step 3 — Using the Docker Command)

Using docker consists of passing it a chain of options and commands followed by arguments. The syntax takes this form:

使用docker包括向其传递一系列选项和命令，后跟参数。 语法采用以下形式：

To view all available subcommands, type:

要查看所有可用的子命令，请键入：

As of Docker 19, the complete list of available subcommands includes:

从Docker 19开始，可用子命令的完整列表包括：

   
   

    
    Output
   
   
  attach      Attach local standard input, output, and error streams to a running container
  build       Build an image from a Dockerfile
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  events      Get real time events from the server
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  history     Show the history of an image
  images      List images
  import      Import the contents from a tarball to create a filesystem image
  info        Display system-wide information
  inspect     Return low-level information on Docker objects
  kill        Kill one or more running containers
  load        Load an image from a tar archive or STDIN
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  logs        Fetch the logs of a container
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  ps          List containers
  pull        Pull an image or a repository from a registry
  push        Push an image or a repository to a registry
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  rmi         Remove one or more images
  run         Run a command in a new container
  save        Save one or more images to a tar archive (streamed to STDOUT by default)
  search      Search the Docker Hub for images
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  tag         Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  version     Show the Docker version information
  wait        Block until one or more containers stop, then print their exit codes

To view the options available to a specific command, type:

要查看特定命令可用的选项，请键入：

To view system-wide information about Docker, use:

要查看有关Docker的系统范围信息，请使用：

Let’s explore some of these commands. We’ll start by working with images.

让我们探索其中一些命令。 我们将从处理图像开始。

第4步—使用Docker映像 (Step 4 — Working with Docker Images)

Docker containers are built from Docker images. By default, Docker pulls these images from Docker Hub, a Docker registry managed by Docker, the company behind the Docker project. Anyone can host their Docker images on Docker Hub, so most applications and Linux distributions you’ll need will have images hosted there.

Docker容器是从Docker映像构建的。 默认情况下，Docker从Docker Hub提取这些映像， Docker Hub是由Docker项目背后的公司Docker管理的Docker注册表。 任何人都可以在Docker Hub上托管其Docker映像，因此您需要的大多数应用程序和Linux发行版都将托管映像。

To check whether you can access and download images from Docker Hub, type:

要检查是否可以从Docker Hub访问和下载映像，请输入：

The output will indicate that Docker in working correctly:

输出将表明Docker在正常工作：

   
   

    
    Output
   
   
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
0e03bdcc26d7: Pull complete
Digest: sha256:6a65f928fb91fcfbc963f7aa6d57c8eeb426ad9a20c7ee045538ef34847f44f1
Status: Downloaded newer image for hello-world:latest

Hello from Docker!
This message shows that your installation appears to be working correctly.

...

Docker was initially unable to find the hello-world image locally, so it downloaded the image from Docker Hub, which is the default repository. Once the image downloaded, Docker created a container from the image and the application within the container executed, displaying the message.

Docker最初无法在本地找到hello-world映像，因此它从默认存储库Docker Hub下载了该映像。 下载映像后，Docker会根据映像创建一个容器，并执行该容器中的应用程序，显示消息。

You can search for images available on Docker Hub by using the docker command with the search subcommand. For example, to search for the Ubuntu image, type:

您可以使用docker命令和search子命令来search Docker Hub上可用的映像。 例如，要搜索Ubuntu映像，请输入：

The script will crawl Docker Hub and return a listing of all images whose name match the search string. In this case, the output will be similar to this:

该脚本将对Docker Hub进行爬网，并返回名称与搜索字符串匹配的所有图像的列表。 在这种情况下，输出将类似于以下内容：

   
   

    
    Output
   
   
NAME                                                      DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
ubuntu                                                    Ubuntu is a Debian-based Linux operating sys…   10908               [OK]
dorowu/ubuntu-desktop-lxde-vnc                            Docker image to provide HTML5 VNC interface …   428                                     [OK]
rastasheep/ubuntu-sshd                                    Dockerized SSH service, built on top of offi…   244                                     [OK]
consol/ubuntu-xfce-vnc                                    Ubuntu container with "headless" VNC session…   218                                     [OK]
ubuntu-upstart                                            Upstart is an event-based replacement for th…   108                 [OK]
ansible/ubuntu14.04-ansible                               Ubuntu 14.04 LTS with 
...

In the OFFICIAL column, OK indicates an image built and supported by the company behind the project. Once you’ve identified the image that you would like to use, you can download it to your computer using the pull subcommand.

在“ 官方”列中，“ 确定”指示由项目背后的公司构建并支持的图像。 一旦确定了要使用的图像，就可以使用pull子命令将其下载到计算机上。

Execute the following command to download the official ubuntu image to your computer:

执行以下命令，将正式的ubuntu映像下载到您的计算机：

You’ll see the following output:

您将看到以下输出：

   
   

    
    Output
   
   
Using default tag: latest
latest: Pulling from library/ubuntu
d51af753c3d3: Pull complete
fc878cd0a91c: Pull complete
6154df8ff988: Pull complete
fee5db0ff82f: Pull complete
Digest: sha256:747d2dbbaaee995098c9792d99bd333c6783ce56150d1b11e333bbceed5c54d7
Status: Downloaded newer image for ubuntu:latest
docker.io/library/ubuntu:latest

After an image has been downloaded, you can then run a container using the downloaded image with the run subcommand. As you saw with the hello-world example, if an image has not been downloaded when docker is executed with the run subcommand, the Docker client will first download the image, then run a container using it.

下载映像后，可以使用带有run子命令的已下载映像来运行容器。 当你用电锯hello-world例如，如果当图像尚未下载docker与执行run子命令，多克尔客户端将首先下载的图像，然后用它运行的容器。

To see the images that have been downloaded to your computer, type:

要查看已下载到计算机的图像，请键入：

The output will look similar to the following:

输出将类似于以下内容：

   
   

    
    Output
   
   
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
ubuntu              latest              1d622ef86b13        3 weeks ago         73.9MB
hello-world         latest              bf756fb1ae65        4 months ago        13.3kB

As you’ll see later in this tutorial, images that you use to run containers can be modified and used to generate new images, which may then be uploaded (pushed is the technical term) to Docker Hub or other Docker registries.

正如您将在本教程的后面看到的那样，可以修改用于运行容器的映像并用于生成新映像，然后可以将其上载(按技术术语推入 )到Docker Hub或其他Docker注册表中。

Let’s look at how to run containers in more detail.

让我们看看如何更详细地运行容器。

第5步—运行Docker容器 (Step 5 — Running a Docker Container)

The hello-world container you ran in the previous step is an example of a container that runs and exits after emitting a test message. Containers can be much more useful than that, and they can be interactive. After all, they are similar to virtual machines, only more resource-friendly.

您在上一步中运行的hello-world容器是一个在发出测试消息后运行并退出的容器的示例。 容器可以比这有用得多，并且它们可以是交互式的。 毕竟，它们类似于虚拟机，但是对资源更友好。

As an example, let’s run a container using the latest image of Ubuntu. The combination of the -i and -t switches gives you interactive shell access into the container:

例如，让我们使用Ubuntu的最新映像运行一个容器。 -i和-t开关的组合使您可以交互式访问外壳：

Your command prompt should change to reflect the fact that you’re now working inside the container and should take this form:

您的命令提示符应更改以反映您正在容器内工作的事实，并应采用以下形式：

   
   

    
    Output
   
   
root@d9b100f2f636:/#

Note the container id in the command prompt. In this example, it is d9b100f2f636. You’ll need that container ID later to identify the container when you want to remove it.

注意命令提示符中的容器ID。 在此示例中，它是d9b100f2f636 。 您以后需要该容器ID来标识要删除的容器。

Now you can run any command inside the container. For example, let’s update the package database inside the container. You don’t need to prefix any command with sudo, because you’re operating inside the container as the root user:

现在，您可以在容器内运行任何命令。 例如，让我们更新容器内的包数据库。 您不需要在任何命令前加上sudo前缀，因为您是在容器内部以root用户身份进行操作的：

Then install any application in it. Let’s install Node.js:

然后在其中安装任何应用程序。 让我们安装Node.js：

This installs Node.js in the container from the official Ubuntu repository. When the installation finishes, verify that Node.js is installed:

这会将Node.js从官方Ubuntu存储库安装到容器中。 安装完成后，请验证是否已安装Node.js：

You’ll see the version number displayed in your terminal:

您会在终端中看到版本号：

   
   

    
    Output
   
   
v10.19.0

Any changes you make inside the container only apply to that container.

您在容器内所做的任何更改仅适用于该容器。

To exit the container, type exit at the prompt.

要退出容器，请在提示符下键入exit 。

Let’s look at managing the containers on our system next.

接下来让我们来看一下管理系统上的容器。

第6步-管理Docker容器 (Step 6 — Managing Docker Containers)

After using Docker for a while, you’ll have many active (running) and inactive containers on your computer. To view the active ones, use:

在使用Docker一段时间后，您的计算机上将有许多活动(运行)和非活动容器。 要查看活动对象 ，请使用：

You will see output similar to the following:

您将看到类似于以下内容的输出：

   
   

    
    Output
   
   
CONTAINER ID        IMAGE               COMMAND             CREATED             

In this tutorial, you started two containers; one from the hello-world image and another from the ubuntu image. Both containers are no longer running, but they still exist on your system.

在本教程中，您启动了两个容器。 一个来自hello-world映像，另一个来自ubuntu映像。 这两个容器都不再运行，但是它们仍然存在于您的系统上。

To view all containers — active and inactive, run docker ps with the -a switch:

要查看所有容器(活动和非活动容器)，请使用-a开关运行docker ps ：

You’ll see output similar to this:

您将看到类似于以下的输出：

1c08a7a0d0e4        ubuntu              "/bin/bash"         2 minutes ago       Exited (0) 8 seconds ago                       quizzical_mcnulty
a707221a5f6c        hello-world         "/hello"            6 minutes ago       Exited (0) 6 minutes ago                       youthful_curie

To view the latest container you created, pass it the -l switch:

要查看您创建的最新容器，请将-l开关传递给它：

To start a stopped container, use docker start, followed by the container ID or the container’s name. Let’s start the Ubuntu-based container with the ID of 1c08a7a0d0e4:

要启动已停止的容器，请使用docker start ，后跟容器ID或容器的名称。 让我们启动ID为1c08a7a0d0e4的基于Ubuntu的容器：

The container will start, and you can use docker ps to see its status:

容器将启动，您可以使用docker ps查看其状态：

   
   

    
    Output
   
   
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
1c08a7a0d0e4        ubuntu              "/bin/bash"         3 minutes ago       Up 5 seconds                            quizzical_mcnulty

To stop a running container, use docker stop, followed by the container ID or name. This time, we’ll use the name that Docker assigned the container, which is quizzical_mcnulty:

要停止正在运行的容器，请使用docker stop ，后跟容器ID或名称。 这次，我们将使用Docker分配的容器名称quizzical_mcnulty ：

Once you’ve decided you no longer need a container anymore, remove it with the docker rm command, again using either the container ID or the name. Use the docker ps -a command to find the container ID or name for the container associated with the hello-world image and remove it.

一旦确定不再需要容器，请使用docker rm命令再次使用容器ID或名称将其删除。 使用docker ps -a命令查找与hello-world映像关联的容器的容器ID或名称，并将其删除。

You can start a new container and give it a name using the --name switch. You can also use the --rm switch to create a container that removes itself when it’s stopped. See the docker run help command for more information on these options and others.

您可以启动一个新容器，并使用--name开关为其命名。 您也可以使用--rm开关创建一个容器，该容器在停止时会自行删除。 有关这些选项和其他选项的更多信息，请参阅docker run help命令。

Containers can be turned into images which you can use to build new containers. Let’s look at how that works.

容器可以转换为映像，您可以使用它们来构建新的容器。 让我们看看它是如何工作的。

步骤7 —将容器中的更改提交给Docker映像 (Step 7 — Committing Changes in a Container to a Docker Image)

When you start up a Docker image, you can create, modify, and delete files just like you can with a virtual machine. The changes that you make will only apply to that container. You can start and stop it, but once you destroy it with the docker rm command, the changes will be lost for good.

启动Docker映像时，可以像使用虚拟机一样创建，修改和删除文件。 您所做的更改将仅应用于该容器。 您可以启动和停止它，但是一旦使用docker rm命令销毁它，更改将永远丢失。

This section shows you how to save the state of a container as a new Docker image.

本节说明如何将容器状态另存为新的Docker映像。

After installing Node.js inside the Ubuntu container, you now have a container running off an image, but the container is different from the image you used to create it. But you might want to reuse this Node.js container as the basis for new images later.

在Ubuntu容器中安装Node.js之后，您现在有了一个运行映像的容器，但是该容器与用于创建它的映像不同。 但是您以后可能希望重用此Node.js容器作为新映像的基础。

Then commit the changes to a new Docker image instance using the following command.

然后使用以下命令将更改提交到新的Docker映像实例。

The -m switch is for the commit message that helps you and others know what changes you made, while -a is used to specify the author. The container_id is the one you noted earlier in the tutorial when you started the interactive Docker session. Unless you created additional repositories on Docker Hub, the repository is usually your Docker Hub username.

-m开关用于提交消息，该消息可帮助您和其他人知道您所做的更改，而-a用于指定作者。 container_id是您在本教程前面部分中启动交互式Docker会话时所注明的那个。 除非您在Docker Hub上创建了其他存储库，否则该repository通常是您的Docker Hub用户名。

For example, for the user sammy, with the container ID of d9b100f2f636, the command would be:

例如，对于用户sammy ，容器ID为d9b100f2f636 ，命令将为：

When you commit an image, the new image is saved locally on your computer. Later in this tutorial, you’ll learn how to push an image to a Docker registry like Docker Hub so others can access it.

提交映像时，新映像将保存在本地计算机上。 在本教程的后面，您将学习如何将映像推送到Docker Hub等Docker注册表，以便其他人可以访问它。

Listing the Docker images again will show the new image, as well as the old one that it was derived from:

再次列出Docker映像将显示新映像，以及来自该映像的旧映像：

You’ll see output like this:

您将看到如下输出：

   
   

    
    Output
   
   
REPOSITORY               TAG                 IMAGE ID            CREATED             SIZE
sammy/ubuntu-nodejs   latest              7c1f35226ca6        7 seconds ago       179MB
...

In this example, ubuntu-nodejs is the new image, which was derived from the existing ubuntu image from Docker Hub. The size difference reflects the changes that were made. And in this example, the change was that NodeJS was installed. So next time you need to run a container using Ubuntu with NodeJS pre-installed, you can just use the new image.

在此示例中， ubuntu-nodejs是新映像，它是从Docker Hub的现有ubuntu映像派生的。 大小差异反映了所做的更改。 在此示例中，更改之处在于已安装NodeJS。 因此，下一次您需要使用预先安装了NodeJS的Ubuntu运行容器时，就可以使用新映像。

You can also build Images from a Dockerfile, which lets you automate the installation of software in a new image. However, that’s outside the scope of this tutorial.

您还可以从Dockerfile构建映像，该文件可让您自动在新映像中安装软件。 但是，这超出了本教程的范围。

Now let’s share the new image with others so they can create containers from it.

现在，让我们与其他人共享新图像，以便他们可以从中创建容器。

步骤8 —将Docker映像推送到Docker存储库 (Step 8 — Pushing Docker Images to a Docker Repository)

The next logical step after creating a new image from an existing image is to share it with a select few of your friends, the whole world on Docker Hub, or other Docker registry that you have access to. To push an image to Docker Hub or any other Docker registry, you must have an account there.

从现有映像创建新映像之后，下一个逻辑步骤是与您的几个朋友，Docker Hub上的整个世界或您有权访问的其他Docker注册表共享该映像。 要将映像推送到Docker Hub或任何其他Docker注册表，您必须在其中拥有一个帐户。

This section shows you how to push a Docker image to Docker Hub. To learn how to create your own private Docker registry, check out How To Set Up a Private Docker Registry on Ubuntu 14.04.

本节介绍如何将Docker映像推送到Docker Hub。 要了解如何创建自己的私有Docker注册表，请查看如何在Ubuntu 14.04上设置私有Docker注册表 。

To push your image, first log into Docker Hub.

要推送映像，请首先登录Docker Hub。

You’ll be prompted to authenticate using your Docker Hub password. If you specified the correct password, authentication should succeed.

系统将提示您使用Docker Hub密码进行身份验证。 如果您指定了正确的密码，则身份验证应该成功。

Note: If your Docker registry username is different from the local username you used to create the image, you will have to tag your image with your registry username. For the example given in the last step, you would type:

注意：如果您的Docker注册表用户名与用于创建映像的本地用户名不同，则必须使用注册表用户名标记映像。 对于最后一步中给出的示例，您将键入：

Then you may push your own image using:

然后，您可以使用以下方法推送自己的图像：

To push the ubuntu-nodejs image to the sammy repository, the command would be:

要将ubuntu-nodejs映像推送到sammy存储库，命令为：

The process may take some time to complete as it uploads the images, but when completed, the output will look like this:

上载图像时，该过程可能需要一些时间才能完成，但是完成后，输出将如下所示：

   
   

    
    Output
   
   
The push refers to a repository [docker.io/sammy/ubuntu-nodejs]
e3fbbfb44187: Pushed
5f70bf18a086: Pushed
a3b5c80a4eba: Pushed
7f18b442972b: Pushed
3ce512daaf78: Pushed
7aae4540b42d: Pushed

...

After pushing an image to a registry, it should be listed on your account’s dashboard, like that show in the image below.

将图片推送到注册表后，应在您的帐户的信息中心上列出该图片，如下图所示。

If a push attempt results in an error of this sort, then you likely did not log in:

如果推送尝试导致此类错误，则您可能未登录：

   
   

    
    Output
   
   
The push refers to a repository [docker.io/sammy/ubuntu-nodejs]
e3fbbfb44187: Preparing
5f70bf18a086: Preparing
a3b5c80a4eba: Preparing
7f18b442972b: Preparing
3ce512daaf78: Preparing
7aae4540b42d: Waiting
unauthorized: authentication required

Log in with docker login and repeat the push attempt. Then verify that it exists on your Docker Hub repository page.

使用docker login并重复推送尝试。 然后验证它是否存在于您的Docker Hub存储库页面上。

You can now use docker pull sammy/ubuntu-nodejs to pull the image to a new machine and use it to run a new container.

您现在可以使用docker pull sammy / ubuntu-nodejs将映像拉到新机器上，并使用它运行新容器。

结论 (Conclusion)

In this tutorial you installed Docker, worked with images and containers, and pushed a modified image to Docker Hub. Now that you know the basics, explore the other Docker tutorials in the DigitalOcean Community.

在本教程中，您安装了Docker，使用了图像和容器，并将修改后的图像推送到Docker Hub。 既然您已经了解了基础知识，请在DigitalOcean社区中探索其他Docker教程 。

翻译自: https://www.digitalocean.com/community/tutorials/how-to-install-and-use-docker-on-ubuntu-20-04