Docker安装

环境需求

Linux，且要求内核3.0以上。

# 查看内核版本
[root@VM-8-9-centos ~]# uname -a
Linux VM-8-9-centos 4.18.0-305.3.1.el8.x86_64 #1 SMP Tue Jun 1 16:14:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
# 查看发行版（本文档采用centos8）
[root@VM-8-9-centos ~]# cat /etc/os-release
NAME="CentOS Linux"
VERSION="8 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="8"
PLATFORM_ID="platform:el8"
PRETTY_NAME="CentOS Linux 8 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:8"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"
CENTOS_MANTISBT_PROJECT="CentOS-8"
CENTOS_MANTISBT_PROJECT_VERSION="8"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="8"

安装

详细安装参考文档，下面只记录命令。https://docs.docker.com/engine/install/centos/。

# 卸载已存在的docker
sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine
# 安装yum工具
yum install -y yum-utils
# 配置docker repo的国内地址
yum-config-manager \
    --add-repo \
    https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# 刷新yum索引
yum makecache fast
# 安装docker相关的 docker-ce 社区版（ee是企业版，要收费）
yum install docker-ce docker-ce-cli containerd.io
# 启动docker
systemctl start docker
# 使用docker version查看是否按照成功
[root@VM-8-9-centos ~]# docker version
Client: Docker Engine - Community
 Version:           20.10.9
 API version:       1.41
 Go version:        go1.16.8
 Git commit:        c2ea9bc
 Built:             Mon Oct  4 16:08:25 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true
Server: Docker Engine - Community
 Engine:
  Version:          20.10.9
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.16.8
  Git commit:       79ea9d3
  Built:            Mon Oct  4 16:06:48 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.11
  GitCommit:        5b46e404f6b9f661a205e28d59c982d3634148f8
 runc:
  Version:          1.0.2
  GitCommit:        v1.0.2-0-g52b36a2
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

卸载Docker

# 卸载依赖
yum remove docker-ce docker-ce-cli containerd.io
# 删除资源，/var/lib/docker 是docker的默认工作路径！
rm -rf /var/lib/docker

配置Docker仓库加速地址

由于我用的是腾讯云轻量应用服务器，所以就使用腾讯云的加速，使用阿里云的可以去搜一下。

# 创建一个文件
vim /etc/docker/daemon.json
# 输入加速地址
{
"registry-mirrors": [
 "https://mirror.ccs.tencentyun.com"
]
}
# 重启Docker
sudo systemctl restart docker

Docker工作流程

docker架构图

Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications. By taking advantage of Docker’s methodologies for shipping, testing, and deploying code quickly, you can significantly reduce the delay between writing code and running it in production.

Docker是一个CS结构的应用管理平台，开发者通过Docker客户端连接上Docker服务器后，就可以在不同的基础环境中运行应用，因为Docker对基础环境提供了抽象。
从图中可以看出，如果想使用Docker运行一个容器。需要先从docker hub上拉取一个镜像，然后启动这个镜像就可以让其作为一个容器运行起来。

Docker命令

帮助命令

docker基本信息

[root@VM-8-9-centos ~]# docker info
Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Build with BuildKit (Docker Inc., v0.6.3-docker)
  scan: Docker Scan (Docker Inc., v0.8.0)
Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 3
 Server Version: 20.10.9
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 1
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 5b46e404f6b9f661a205e28d59c982d3634148f8
 runc version: v1.0.2-0-g52b36a2
 init version: de40ad0
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 4.18.0-305.3.1.el8.x86_64
 Operating System: CentOS Linux 8 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 3.649GiB
 Name: VM-8-9-centos
 ID: RWPV:56TQ:L2XR:PRWM:UYGT:A2MU:PJXQ:BUFW:7TUK:AEH2:XOA7:BTAT
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Registry Mirrors:
  https://mirror.ccs.tencentyun.com/
 Live Restore Enabled: false

从上面输出的信息中可以看出来Docker的基本信息，比如docker的版本，当前docker拥有几个镜像，Linux的版本，机子的信息，镜像仓库的地址。

docker帮助命令

# 查看docker的命令
docker help
# 查看命令的帮助文档
docker 命令 --help

镜像命令

搜索镜像

[root@VM-8-9-centos ~]# docker search mysql
NAME                              DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
mysql                             MySQL is a widely used, open-source relation…   11521     [OK]
mariadb                           MariaDB Server is a high performing open sou…   4373      [OK]
mysql/mysql-server                Optimized MySQL Server Docker images. Create…   851                  [OK]
centos/mysql-57-centos7           MySQL 5.7 SQL database server                   91
mysql/mysql-cluster               Experimental MySQL Cluster Docker images. Cr…   88
centurylink/mysql                 Image containing mysql. Optimized to be link…   59                   [OK]
databack/mysql-backup             Back up mysql databases to... anywhere!         51
prom/mysqld-exporter                                                              42                   [OK]
deitch/mysql-backup               REPLACED! Please use http://hub.docker.com/r…   41                   [OK]
tutum/mysql                       Base docker image to run a MySQL database se…   35
linuxserver/mysql                 A Mysql container, brought to you by LinuxSe…   32
schickling/mysql-backup-s3        Backup MySQL to S3 (supports periodic backup…   31                   [OK]
mysql/mysql-router                MySQL Router provides transparent routing be…   23
centos/mysql-56-centos7           MySQL 5.6 SQL database server                   20
arey/mysql-client                 Run a MySQL client from a docker container      18                   [OK]
fradelg/mysql-cron-backup         MySQL/MariaDB database backup using cron tas…   16                   [OK]
yloeffler/mysql-backup            This image runs mysqldump to backup data usi…   7                    [OK]
genschsa/mysql-employees          MySQL Employee Sample Database                  7                    [OK]
openshift/mysql-55-centos7        DEPRECATED: A Centos7 based MySQL v5.5 image…   6
idoall/mysql                      MySQL is a widely used, open-source relation…   3                    [OK]
devilbox/mysql                    Retagged MySQL, MariaDB and PerconaDB offici…   3
jelastic/mysql                    An image of the MySQL database server mainta…   2
ansibleplaybookbundle/mysql-apb   An APB which deploys RHSCL MySQL                2                    [OK]
widdpim/mysql-client              Dockerized MySQL Client (5.7) including Curl…   1                    [OK]
centos/mysql-80-centos7           MySQL 8.0 SQL database server                   1

除了使用docker search搜索，我们还可以去docker hub上搜索，一般最常用的还是去docker hub上搜索。

下载镜像

# 下载镜像是可以携带版本号，也可以不携带，如果不携带默认使用最新版，但是使用时一般都会携带版本号。
# docker pull 镜像名:tag
[root@VM-8-9-centos ~]# docker pull nginx:1.21.3
1.21.3: Pulling from library/nginx
07aded7c29c6: Already exists
bbe0b7acc89c: Pull complete
44ac32b0bba8: Pull complete
91d6e3e593db: Pull complete
8700267f2376: Pull complete
4ce73aa6e9b0: Pull complete
Digest: sha256:06e4235e95299b1d6d595c5ef4c41a9b12641f6683136c18394b858967cd1506
Status: Downloaded newer image for nginx:1.21.3
docker.io/library/nginx:1.21.3

如果不知道镜像的名字或版本号就可以去docker hub上搜索。

查看本地镜像

[root@VM-8-9-centos ~]# docker images
REPOSITORY    TAG       IMAGE ID       CREATED       SIZE
nginx         1.21.3    f8f4ffc8092c   13 days ago   133MB
mysql         latest    2fe463762680   13 days ago   514MB
hello-world   latest    feb5d9fea6a5   2 weeks ago   13.3kB
centos        latest    5d0da3dc9764   3 weeks ago   231MB

解释

REPOSITORY            镜像名
TAG                            标签
IMAGE ID                镜像ID
CREATED                    创建时间
SIZE                        镜像大小

可选项

# -a  Show all images (default hides intermediate images)
# -q  Only show image IDs
[root@VM-8-9-centos ~]# docker images -a
REPOSITORY    TAG       IMAGE ID       CREATED       SIZE
nginx         1.21.3    f8f4ffc8092c   13 days ago   133MB
mysql         latest    2fe463762680   13 days ago   514MB
hello-world   latest    feb5d9fea6a5   2 weeks ago   13.3kB
centos        latest    5d0da3dc9764   3 weeks ago   231MB
[root@VM-8-9-centos ~]# docker images -q
f8f4ffc8092c
2fe463762680
feb5d9fea6a5
5d0da3dc9764

参数

# docker images 镜像名
[root@VM-8-9-centos ~]# docker images nginx
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
nginx        1.21.3    f8f4ffc8092c   13 days ago   133MB

删除镜像

# docker rmi 镜像名/镜像ID
[root@VM-8-9-centos ~]# docker rmi hello-world
Untagged: hello-world:latest
Untagged: hello-world@sha256:9ade9cc2e26189a19c2e8854b9c8f1e14829b51c55a630ee675a5a9540ef6ccf
Deleted: sha256:feb5d9fea6a5e9606aa995e879d862b825965ba48de054caab5ef356dc6b3412
Deleted: sha256:e07ee1baac5fae6a26f30cabfe54a36d3402f96afda318fe0a96cec4ca393359
[root@VM-8-9-centos ~]# docker images -a
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
nginx        1.21.3    f8f4ffc8092c   13 days ago   133MB
mysql        latest    2fe463762680   13 days ago   514MB
centos       latest    5d0da3dc9764   3 weeks ago   231MB

删除全部镜像：

docker rmi -f $(docker images -aq)；
docker images -q | xargs docker rmi。
容器命令
运行容器
```
# 基础用法：docker run -d -p 宿主机端口:容器端口 --name="容器名" 镜像名:版本
# docker run -d -p 8080:80 --name="mynginx" nginx:1.21.3
```
镜像类比为一个安装包，是一个静态的概念，容器类比为一个运行的应用，是一个动态的概念。每个容器都有一个唯一的容器名，可以通过—name指定容器名，如果不指定，会使用随机的名称。
当我们运行容器之后，容器是一个单独的环境，理解为Linux中又启动了一个Linux。所以容器开启的端口不是宿主机的端口，上面的命令表示，容器本身开启了一个80端口，宿主机开启了一个8080端口映射到容器，所以如果需要从客户端访问到容器内的服务，需要使用8080端口。不能使用80端口。
默认容器的启动是以前台方式进行的，-d可选项表示容器以后台方式运行。 ```bash [root@VM-8-9-centos ~]# docker run -d -p 8080:80 —name=”mynginx” nginx:1.21.3 d0de55896281ead7c0cab5596ff884d0bd849965147a4d02cbc6cb013692c459 [root@VM-8-9-centos ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d0de55896281 nginx:1.21.3 “/docker-entrypoint.…” 2 seconds ago Up 2 seconds 0.0.0.0:8080->80/tcp, :::8080->80/tcp mynginx [root@VM-8-9-centos ~]# curl localhost:8080 <!DOCTYPE html>
Welcome to nginx!
If you see this page, the nginx web server is successfully installed and working. Further configuration is required.

For online documentation and support please refer to nginx.org.
Commercial support is available at nginx.com.

Thank you for using nginx.

[root@VM-8-9-centos ~]# curl localhost:80 curl: (7) Failed to connect to localhost port 80: Connection refused [root@VM-8-9-centos ~]#

<a name="i3ytJ"></a>
### 进入容器
上面讲到，容器本身就是一个linux，所以我们自然可以登录到容器中。

bash # docker exec -i -t 容器名/容器ID shell # docker exec 是在容器中运行命令，通过我们会通过这个命令开一个shell终端，再在shell终端中执行业务命令 # -i : Keep STDIN open even if not attached # -t : Allocate a pseudo-TTY，分配一个伪终端。为啥是”伪”呢，暂不明白。 docker exec -i -t mynginx /bin/bash [root@VM-8-9-centos ~]# docker exec -i -t mynginx /bin/bash root@d0de55896281:/# ll bash: ll: command not found root@d0de55896281:/# ls bin boot dev docker-entrypoint.d docker-entrypoint.sh etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var root@d0de55896281:/# exit; exit [root@VM-8-9-centos ~]# docker exec -i -t mynginx /bin/bash root@d0de55896281:/# ls -a . .dockerenv boot docker-entrypoint.d etc lib media opt root sbin sys usr .. bin dev docker-entrypoint.sh home lib64 mnt proc run srv tmp var root@d0de55896281:/# curl localhost:80 <!DOCTYPE html>

Welcome to nginx!

If you see this page, the nginx web server is successfully installed and working. Further configuration is required.

For online documentation and support please refer to nginx.org.
Commercial support is available at nginx.com.

Thank you for using nginx.

root@d0de55896281:/# exit exit

进入到正在运行的容器之后，我们就可以执行我们想要的指令。因为它本身就可以理解为一个Linux系统，但是这个Linux系统通常很简单，很多指令都不支持。<br />退出容器使用exit。<br />如果想运行容器时立刻打开一个此容器的shell终端，可以在docker run上增加可选项-it。

bash [root@VM-8-9-centos ~]# docker run -it nginx:1.21.3 /bin/bash root@1e9fdc40a104:/# ls -a . .dockerenv boot docker-entrypoint.d etc lib media opt root sbin sys usr .. bin dev docker-entrypoint.sh home lib64 mnt proc run srv tmp var root@1e9fdc40a104:/# curl localhost curl: (7) Failed to connect to localhost port 80: Connection refused root@1e9fdc40a104:/# exit exit

但进入之后我们会发现nginx没有启动，这是因为docker run命令携带的参数/bin/bash覆盖了启动nginx的命令。前面提到过，docker容器可以理解为一个小型的linux，在制作docker镜像的时候，通过会写一些启动命令，这样在容器启动之后服务就会启动了。这些启动命令是可以被替换的，上面我们就是用/bin/bash替换了默认的命令，导致nginx无法启动。所以通过想进入容器，都会选择先启动容器，在docker exec执行/bin/bash开启一个能和docker交互的终端。
<a name="r30CB"></a>
### 查看容器

bash 查看正在运行的容器 docker ps # 查看全部容器 -a docker pa -a [root@VM-8-9-centos ~]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 1e9fdc40a104 nginx:1.21.3 “/docker-entrypoint.…” 37 minutes ago Exited (7) 36 minutes ago confident_hofstadter d0de55896281 nginx:1.21.3 “/docker-entrypoint.…” About an hour ago Up About an hour 0.0.0.0:8080->80/tcp, :::8080->80/tcp mynginx [root@VM-8-9-centos ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d0de55896281 nginx:1.21.3 “/docker-entrypoint.…” About an hour ago Up About an hour 0.0.0.0:8080->80/tcp, :::8080->80/tcp mynginx

容器是有生命状态的，包含：Stop、Running和Pause三个状态。docker ps只能看见处于Running和Pause状态的容器，看不见处于Stop状态的容器。

bash [root@VM-8-9-centos ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 1fb0fd6f5272 nginx:1.21.3 “/docker-entrypoint.…” 2 minutes ago Up 2 minutes (Paused) 0.0.0.0:8082->80/tcp, :::8082->80/tcp mynginx3 d0de55896281 nginx:1.21.3 “/docker-entrypoint.…” 20 hours ago Up 20 hours 0.0.0.0:8080->80/tcp, :::8080->80/tcp mynginx [root@VM-8-9-centos ~]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 1fb0fd6f5272 nginx:1.21.3 “/docker-entrypoint.…” 2 minutes ago Up 2 minutes (Paused) 0.0.0.0:8082->80/tcp, :::8082->80/tcp mynginx3 d6051e48450c nginx:1.21.3 “/docker-entrypoint.…” 3 minutes ago Exited (0) 43 seconds ago mynginx2 d0de55896281 nginx:1.21.3 “/docker-entrypoint.…” 20 hours ago Up 20 hours 0.0.0.0:8080->80/tcp, :::8080->80/tcp mynginx

<a name="COJ6J"></a>
### 停止容器 & 暂停容器
![image.png](https://cdn.nlark.com/yuque/0/2021/png/726149/1634121173289-552b8cd1-7f59-47f2-b599-e92d515f0826.png#clientId=u96bbaf5a-f6dd-4&from=paste&height=511&id=u4595e824&margin=%5Bobject%20Object%5D&name=image.png&originHeight=1022&originWidth=1444&originalType=binary&ratio=1&size=98670&status=done&style=none&taskId=ueffefd0a-317c-4004-a8ec-765ba8093fb&width=722)<br />暂停容器、启动容器、停止容器、重启容器的命令都很简单：docker pause、docker start、docker stop和docker restart。<br />Pause状态和Stop状态类似于电脑关机和电脑休眠，Pause时不消耗CPU，但是依然占据内存，Stop时CPU和内存都不再占据。所以对于被pause的容器，unpause之后，容器内部服务的Context不会改变。但是对于start或restart的容器，容器内部服务的Context会改变。<br />我们请求一下容器内部的服务看看。

bash [root@VM-8-9-centos ~]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b38784365688 nginx:1.21.3 “/docker-entrypoint.…” 13 seconds ago Up 13 seconds 0.0.0.0:8080->80/tcp, :::8080->80/tcp mynginx1 1fb0fd6f5272 nginx:1.21.3 “/docker-entrypoint.…” 31 minutes ago Up 11 minutes (Paused) 0.0.0.0:8082->80/tcp, :::8082->80/tcp mynginx3 d6051e48450c nginx:1.21.3 “/docker-entrypoint.…” 31 minutes ago Exited (0) 29 minutes ago mynginx2 # 处于running状态的容器正常返回 [root@VM-8-9-centos ~]# curl localhost:8080 <!DOCTYPE html>

Welcome to nginx!

If you see this page, the nginx web server is successfully installed and working. Further configuration is required.

For online documentation and support please refer to nginx.org.
Commercial support is available at nginx.com.

Thank you for using nginx.

处于Stop状态的容器拒绝服务

[root@VM-8-9-centos ~]# curl localhost:8081 curl: (7) Failed to connect to localhost port 8081: Connection refused

处于Pause状态的服务可以接受请求但是不返回结果，因为它申请不到CPU资源。

[root@VM-8-9-centos ~]# curl localhost:8082 ^C

<a name="sC1mj"></a>
### 输出容器状态
**查看容器内部进程**
```bash
# docker top 容器ID
[root@VM-8-9-centos ~]# docker top 1f
UID                 PID                 PPID                C                   STIME               TTY                 TIME                CMD
root                3731429             3731409             0                   18:33               ?                   00:00:00            nginx: master process nginx -g daemon off;
101                 3731473             3731429             0                   18:33               ?                   00:00:00            nginx: worker process
101                 3731474             3731429             0                   18:33               ?                   00:00:00            nginx: worker process

从docker top的输出中看出一些容器的进程信息，比如进程的个数，进程的PID以及PPID，进程的创建时间以及创建命令。从上图可以看出nginx创建了一个主进程（用于接收请求），两个工作进程（用于处理请求）。
查看容器状态

# docker stats 容器ID
CONTAINER ID   NAME       CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O     PIDS
b38784365688   mynginx1   0.00%     2.676MiB / 3.649GiB   0.07%     2.53kB / 2.55kB   0B / 8.19kB   3

docker stats可以查看容器的资源使用情况，并且可以动态刷新，类似于Linux的top命令。

删除容器

删除容器使用docker rm命令。与删除镜像容器类似。

[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE          COMMAND                  CREATED             STATUS                         PORTS                                   NAMES
b38784365688   nginx:1.21.3   "/docker-entrypoint.…"   51 minutes ago      Up 51 minutes                  0.0.0.0:8080->80/tcp, :::8080->80/tcp   mynginx1
1fb0fd6f5272   nginx:1.21.3   "/docker-entrypoint.…"   About an hour ago   Up About an hour (Paused)      0.0.0.0:8082->80/tcp, :::8082->80/tcp   mynginx3
d6051e48450c   nginx:1.21.3   "/docker-entrypoint.…"   About an hour ago   Exited (0) About an hour ago                                           mynginx2
[root@VM-8-9-centos ~]# docker rm 1f
Error response from daemon: You cannot remove a paused container 1fb0fd6f5272ef99249ce6effccf5be5a50ddcb887c388a045e4e812b015bf06. Unpause and then stop the container before attempting removal or force remove
[root@VM-8-9-centos ~]# docker stop 1f
d1f
[root@VM-8-9-centos ~]# docker rm 1f
1f
[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE          COMMAND                  CREATED             STATUS                         PORTS                                   NAMES
b38784365688   nginx:1.21.3   "/docker-entrypoint.…"   52 minutes ago      Up 52 minutes                  0.0.0.0:8080->80/tcp, :::8080->80/tcp   mynginx1
d6051e48450c   nginx:1.21.3   "/docker-entrypoint.…"   About an hour ago   Exited (0) About an hour ago                                           mynginx2

需要注意的是，当容器处于Running或Pause状态时，是不能删除容器的，需要先停止再删除或者加上可选项-f来强制删除。
删除全部容器：

rm -f docker rm -f $(dockerps -aq)；
docker ps -a -q | xargs docker rm -f。

容器是依托镜像存在的，所以当一个镜像被用于生成容器之后，这个镜像是不能删除的，得等到依托它创建的容器都被删除之后才能删除或者在docker rmi命令上增加-f可选项来强制删除。

后台运行

之前知道，使用docker run -d是后台运行。但是需要注意一点，如果你启动的镜像里没有一个守护进程（能持续对外提供服务），此镜像是会自动stop的。

[root@VM-8-9-centos ~]# docker images -a
REPOSITORY   TAG              IMAGE ID       CREATED        SIZE
nginx        1.21.3           87a94228f133   37 hours ago   133MB
centos       centos8.4.2105   5d0da3dc9764   3 weeks ago    231MB
[root@VM-8-9-centos ~]# docker run -d 5d
9b3783f131d33926ca0b1096951490f078c6427f709c092a19cebcffd01f14c8
[root@VM-8-9-centos ~]# docker run -d 87
376f0e7db9c6dc7d22b92db3b1120835cd1c0b24fa9e1ba42a0c30e407e2719e
[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS                      PORTS     NAMES
376f0e7db9c6   87        "/docker-entrypoint.…"   4 seconds ago    Up 3 seconds                80/tcp    amazing_yalow
9b3783f131d3   5d        "/bin/bash"              14 seconds ago   Exited (0) 13 seconds ago             eloquent_feynman

上图我们启动了一个centos8和一个nginx，由于centos8里没有守护进程，所以它自动stop了。而nginx有处于用户态的进程，所以，处于Running的状态。
执行如下命令：

docker run -d centos /bin/sh -c "for i in {1..50}; do echo $i; sleep 1; done"

启动之后，我们使用watch -n 1 ‘docker ps -a’。
就可以发现，在前50秒，此容器是处于Up状态的，50秒后容器就Exit了。

怎么解决这个问题呢？很简单，以交互模式开启一个shell进程就可以了。

[root@VM-8-9-centos ~]# docker run -d -it 5d /bin/bash
f976950a42b4e2fb699cde3076146e77dd2f68e0d10c486ae38722a2aedde084
[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS                      PORTS     NAMES
f976950a42b4   5d        "/bin/bash"              4 seconds ago    Up 3 seconds                          silly_nobel
a025d52202d7   5d        "/bin/bash"              23 seconds ago   Exited (0) 22 seconds ago             reverent_snyder
376f0e7db9c6   87        "/docker-entrypoint.…"   11 minutes ago   Up 11 minutes               80/tcp    amazing_yalow
9b3783f131d3   5d        "/bin/bash"              11 minutes ago   Exited (0) 11 minutes ago             eloquent_feynman

此时就可以看见，f9这个容器是正常启动的。所以我的理解就是如果既没有用户态进程，又没有可交互的终端，docker会认为这个容器没有价值，就给它停了。
我们再看一个细节，就是docker ps的输出中COMMAND这一列。

[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE         COMMAND                  CREATED          STATUS                      PORTS     NAMES
89ad4394806c   hello-world   "/hello"                 4 seconds ago    Exited (0) 3 seconds ago              loving_morse
cc357ba877a3   5d            "/bin/bash"              20 minutes ago   Up 20 minutes                         eloquent_saha
f976950a42b4   5d            "/bin/bash"              35 minutes ago   Up 35 minutes                         silly_nobel
a025d52202d7   5d            "/bin/bash"              35 minutes ago   Exited (0) 35 minutes ago             reverent_snyder
376f0e7db9c6   87            "/docker-entrypoint.…"   46 minutes ago   Up 46 minutes               80/tcp    amazing_yalow
9b3783f131d3   5d            "/bin/bash"              46 minutes ago   Exited (0) 46 minutes ago             eloquent_feynman

可以发现每个容器启动之后都会执行一个命令，centos8容器是一个bash窗口，nginx容器是一个nginx的启动脚本。

[root@VM-8-9-centos ~]# docker run -it 5d /bin/bash
[root@ade15ea3850d /]#

如果我们使用前台命令运行，也需要以交互模式运行，否则容器会自动stop，因为即使是以前台方式运行，但是无法进行交互，容器也是无价值的。

查看控制台输出

上面提到，每个容器在启动之后都会执行一个命令，那么这个命名在执行的时候是可能在控制台上打印一些日志的。查看这些输出需要使用docker logs命令。

[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE          COMMAND                  CREATED          STATUS          PORTS     NAMES
10d71843a63f   nginx:1.21.3   "/docker-entrypoint.…"   7 minutes ago    Up 4 minutes    80/tcp    awesome_hopper
2f20c79ffaf2   centos         "/bin/sh -c 'while t…"   11 minutes ago   Up 11 minutes             zealous_brattain
# -t 行前输出日志打印的时间
# -f 以follow模式运行
# --tail n 显示末尾n行
[root@VM-8-9-centos ~]# docker logs -t -f --tail 12 10
2021-10-14T10:40:03.745367518Z 10-listen-on-ipv6-by-default.sh: info: IPv6 listen already enabled
2021-10-14T10:40:03.745500346Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
2021-10-14T10:40:03.748270887Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
2021-10-14T10:40:03.749476173Z /docker-entrypoint.sh: Configuration complete; ready for start up
2021-10-14T10:40:03.753653093Z 2021/10/14 10:40:03 [notice] 1#1: using the "epoll" event method
2021-10-14T10:40:03.753666392Z 2021/10/14 10:40:03 [notice] 1#1: nginx/1.21.3
2021-10-14T10:40:03.753690583Z 2021/10/14 10:40:03 [notice] 1#1: built by gcc 8.3.0 (Debian 8.3.0-6)
2021-10-14T10:40:03.753695450Z 2021/10/14 10:40:03 [notice] 1#1: OS: Linux 4.18.0-305.3.1.el8.x86_64
2021-10-14T10:40:03.753699459Z 2021/10/14 10:40:03 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2021-10-14T10:40:03.753752419Z 2021/10/14 10:40:03 [notice] 1#1: start worker processes
2021-10-14T10:40:03.754481107Z 2021/10/14 10:40:03 [notice] 1#1: start worker process 25
2021-10-14T10:40:03.754494278Z 2021/10/14 10:40:03 [notice] 1#1: start worker process 26

上面是我启动了一个nginx，nginx启动的时候会执行docker-entrypoint.sh脚本，脚本执行的时候会在控制台上打印一些日志。

文件拷贝

控制台的日志一般是一些基本的服务启动信息，完整的日志会写在日志文件中，所以一种看日志的方式就是进入容器看，因为容器就是一个Linux。但是容器本身的Linux功能很少，所以一般还是将日志拷贝出来比较方便。
从容器内部拷贝文件出来的命令是docker cp。

[root@VM-8-9-centos ~]# docker run -d -it --name="mycentos" centos:centos8.4.2105 /bin/bash
c57aaf10844578bb1165a675fcb81e399603c8c67f979ecc7ec852fd806be69a
[root@VM-8-9-centos ~]# docker exec -i -t mycentos /bin/bash
[root@c57aaf108445 /]# echo "1">test
[root@c57aaf108445 /]# cat test
1
[root@c57aaf108445 /]# exit
exit
[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE                   COMMAND                  CREATED              STATUS              PORTS                                   NAMES
c57aaf108445   centos:centos8.4.2105   "/bin/bash"              About a minute ago   Up About a minute                                           mycentos
671a4427be55   nginx:1.21.3            "/docker-entrypoint.…"   4 minutes ago        Up 4 minutes        0.0.0.0:8080->80/tcp, :::8080->80/tcp   mynginx
# docker cp 容器ID:绝对路径 绝对路径
[root@VM-8-9-centos ~]# docker cp c57aaf10844:/test /test2
[root@VM-8-9-centos ~]# cat /test2
1

容器启动的思考

docker镜像可以理解为一个安装了应用的Linux系统，docker容器可以理解为一个运行了服务的Linux系统。容器的启动应该是一个Linux的内核和一个Linux终端，然后在终端上执行一个命令或脚本来启动服务。从之前的测试中可以看出来，centos8容器启动之后会启动/bin/bash这个应用，nginx容器启动之后会执行docker-entrypoint.sh来启动nginx。
如果启动容器之后既没有用户态进程，又没有可交互的终端，docker会认为这个容器没有价值，就给它停了。
启动应用的终端除了使用之前提到过的docker logs查看输出以外，还可以使用docker attach连接到这个终端上。

[root@VM-8-9-centos ~]# docker run -d centos /bin/sh -c "while true;do echo 6666;sleep 1;done"
17144183aec951ed19b825ba35e6bd28ae8e8bbfaa761ecf467fca7b73aee34e
[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE          COMMAND                  CREATED          STATUS                        PORTS                                   NAMES
17144183aec9   centos         "/bin/sh -c 'while t…"   2 seconds ago    Up 1 second                                                           busy_benz
e042f05fae1f   centos         "/bin/sh 'while true…"   24 seconds ago   Exited (127) 23 seconds ago                                           modest_gould
671a4427be55   nginx:1.21.3   "/docker-entrypoint.…"   53 minutes ago   Up 53 minutes                 0.0.0.0:8080->80/tcp, :::8080->80/tcp   mynginx
[root@VM-8-9-centos ~]# docker attach 171
6666
6666
6666
6666

连接到这个终端上感觉也没什么价值。毕竟可以使用docker logs查看终端的输出。

镜像制作

容器提交为镜像

nginx有一个默认的启动页面，我们将其修改为Hello World。

[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE          COMMAND                  CREATED             STATUS             PORTS                                   NAMES
671a4427be55   nginx:1.21.3   "/docker-entrypoint.…"   About an hour ago   Up About an hour   0.0.0.0:8080->80/tcp, :::8080->80/tcp   mynginx
[root@VM-8-9-centos ~]# docker exec -it 67 /bin/bash
root@671a4427be55:/# cd /usr/share/nginx/html
root@671a4427be55:/usr/share/nginx/html# ls -a -l
total 16
drwxr-xr-x 2 root root 4096 Oct 12 02:03 .
drwxr-xr-x 3 root root 4096 Oct 12 02:03 ..
-rw-r--r-- 1 root root  497 Sep  7 15:21 50x.html
-rw-r--r-- 1 root root  615 Sep  7 15:21 index.html
root@671a4427be55:/usr/share/nginx/html# echo "Hello World" > index.html
root@671a4427be55:/usr/share/nginx/html# curl localhost
Hello World

如果换了新的服务器，那么还需要修改这个文件，所以为了能方便ship，这个容器可以被提交为镜像。

# -a author
# -m commit message
[root@VM-8-9-centos ~]# docker commit -a "addenda" -m "index page change" 671a4427be55 addenda_nginx:v1.0
sha256:9e07a3f2860b1e904dc6c740c26fdf6fdb56ea5075d500025969b255df052d15
[root@VM-8-9-centos ~]# docker images
REPOSITORY      TAG              IMAGE ID       CREATED         SIZE
addenda_nginx   v1.0             9e07a3f2860b   5 seconds ago   133MB
nginx           1.21.3           87a94228f133   2 days ago      133MB
hello-world     latest           feb5d9fea6a5   2 weeks ago     13.3kB
centos          centos8.4.2105   5d0da3dc9764   4 weeks ago     231MB
centos          latest           5d0da3dc9764   4 weeks ago     231MB
[root@VM-8-9-centos ~]# docker run -d -p 8081:80 addenda_nginx:v1.0
b05ad7d463503f72e59da6efec812ceb20538d64589be8868923d1f292ed0a71
[root@VM-8-9-centos ~]# docker ps -a
CONTAINER ID   IMAGE                COMMAND                  CREATED         STATUS         PORTS                                   NAMES
b05ad7d46350   addenda_nginx:v1.0   "/docker-entrypoint.…"   2 seconds ago   Up 2 seconds   0.0.0.0:8081->80/tcp, :::8081->80/tcp   beautiful_greider
671a4427be55   nginx:1.21.3         "/docker-entrypoint.…"   2 hours ago     Up 6 minutes   0.0.0.0:8080->80/tcp, :::8080->80/tcp   mynginx
[root@VM-8-9-centos ~]# curl localhost:8081
Hello World

镜像打包 & 镜像加载

[root@VM-8-9-centos ~]# docker images
REPOSITORY      TAG              IMAGE ID       CREATED             SIZE
addenda_nginx   v1.0             9e07a3f2860b   About an hour ago   133MB
nginx           1.21.3           87a94228f133   2 days ago          133MB
hello-world     latest           feb5d9fea6a5   2 weeks ago         13.3kB
centos          centos8.4.2105   5d0da3dc9764   4 weeks ago         231MB
centos          latest           5d0da3dc9764   4 weeks ago         231MB
# docker save，默认的输出流是STDOUT，-o可选项是输出到文件
[root@VM-8-9-centos ~]# docker save -o addenda_nginx.tar addenda_nginx:v1.0
[root@VM-8-9-centos ~]# ll
total 134344
-rw------- 1 root root 137564672 Oct 14 21:47 addenda_nginx.tar
[root@VM-8-9-centos ~]# docker rmi addenda_nginx:v1.0
Untagged: addenda_nginx:v1.0
Deleted: sha256:9e07a3f2860b1e904dc6c740c26fdf6fdb56ea5075d500025969b255df052d15
Deleted: sha256:d758613c98a6b43089bf68ddd7d847604c5a37c800c3a3615f06d621bcf36a5e
[root@VM-8-9-centos ~]# docker images
REPOSITORY    TAG              IMAGE ID       CREATED       SIZE
nginx         1.21.3           87a94228f133   2 days ago    133MB
hello-world   latest           feb5d9fea6a5   2 weeks ago   13.3kB
centos        centos8.4.2105   5d0da3dc9764   4 weeks ago   231MB
centos        latest           5d0da3dc9764   4 weeks ago   231MB
# docker load，默认的输入流是STDIN，-i可选项是从文件夹读取
[root@VM-8-9-centos ~]# docker load -i addenda_nginx.tar
59d19ee14d22: Loading layer [==================================================>]  17.41kB/17.41kB
Loaded image: addenda_nginx:v1.0
[root@VM-8-9-centos ~]# docker images
REPOSITORY      TAG              IMAGE ID       CREATED             SIZE
addenda_nginx   v1.0             9e07a3f2860b   About an hour ago   133MB
nginx           1.21.3           87a94228f133   2 days ago          133MB
hello-world     latest           feb5d9fea6a5   2 weeks ago         13.3kB
centos          centos8.4.2105   5d0da3dc9764   4 weeks ago         231MB
centos          latest           5d0da3dc9764   4 weeks ago         231MB
[root@VM-8-9-centos ~]# docker run -d -p 8081:80 addenda_nginx:v1.0
ffbc8db810514d1f569535385c1cd827be7fc3b85db4bb159f77ee99f31ad288
[root@VM-8-9-centos ~]# curl localhost:8081
Hello World

镜像发布到docker hub

镜像发布需要先去docker hub上注册一个账户。
然后需要将本地的镜像打一个tag。

# docker tag local-image:tagname new-repo:tagname
[root@VM-8-9-centos ~]# docker tag addenda_nginx:v1.0 addenda1998/addenda_nginx:v1.0

[root@VM-8-9-centos ~]# docker login -u addenda1998 -p password
WARNING! Using --password via the CLI is insecure. Use --password-stdin.
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeeded

推送

[root@VM-8-9-centos ~]# docker push  addenda1998/addenda_nginx:v1.0
The push refers to repository [docker.io/addenda1998/addenda_nginx]
59d19ee14d22: Pushed
9959a332cf6e: Mounted from library/nginx
f7e00b807643: Mounted from library/nginx
f8e880dfc4ef: Mounted from library/nginx
788e89a4d186: Mounted from library/nginx
43f4e41372e4: Mounted from library/nginx
e81bff2725db: Mounted from library/nginx
v1.0: digest: sha256:84e8bffdd2f727db1d05421bc3d32ab743fd6b10acd8b8f926ff619416ae59eb size: 1778

退出

[root@VM-8-9-centos ~]# docker logout
Removing login credentials for https://index.docker.io/v1/

在docker hub上就能看见了。

镜像发布到腾讯云

由于在国内docker hub不好用，所以我们一般将镜像推送到阿里云或腾讯云的镜像仓库，由于写测试的服务器是腾讯云的，所以这里就以腾讯云仓库镜像来演示了。

[root@VM-8-9-centos ~]# docker tag addenda_nginx:v1.0 ccr.ccs.tencentyun.com/addenda/addenda_learn:v1.0
[root@VM-8-9-centos ~]# docker login --username=100003170363 ccr.ccs.tencentyun.com
Password:
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeeded
[root@VM-8-9-centos ~]# docker push ccr.ccs.tencentyun.com/addenda/addenda_learn:v1.0
The push refers to repository [ccr.ccs.tencentyun.com/addenda/addenda_learn]
59d19ee14d22: Pushed
9959a332cf6e: Pushed
f7e00b807643: Pushed
f8e880dfc4ef: Pushed
788e89a4d186: Pushed
43f4e41372e4: Pushed
e81bff2725db: Pushed
v1.0: digest: sha256:84e8bffdd2f727db1d05421bc3d32ab743fd6b10acd8b8f926ff619416ae59eb size: 1778
[root@VM-8-9-centos ~]# docker logout
Removing login credentials for https://index.docker.io/v1/

唯一的区别就是docker镜像的地址不同。其他步骤和docker hub一致。

推送成功之后就可以在腾讯云上看见了。
需要注意，如果设置为私有镜像，那么需要登录后才能docker pull。

docker

Docker基础

Docker安装

环境需求

安装

卸载Docker

配置Docker仓库加速地址

Docker工作流程

docker架构图

Docker命令

帮助命令

docker基本信息

docker帮助命令

镜像命令

搜索镜像

下载镜像

查看本地镜像

删除镜像

容器命令

运行容器

Welcome to nginx!

Welcome to nginx!

Welcome to nginx!

处于Stop状态的容器拒绝服务

处于Pause状态的服务可以接受请求但是不返回结果，因为它申请不到CPU资源。

删除容器

后台运行

查看控制台输出

文件拷贝

容器启动的思考

镜像制作

容器提交为镜像

镜像打包 & 镜像加载

镜像发布到docker hub

镜像发布到腾讯云

Docker基础命令总结