【Quickstart Docker】$2-2 容器进入和退出

港控/mmm° 2024-02-19 22:12 69阅读 0赞

捕获容器进入和退出（attach + CTRL\_P,CTRL\_Q）

##### 1. 通过attach方式进入容器 #####

root@hoas ~]# docker run -itd hoas/jdk1.8:19081902 /bin/bash
    a0e0561224336806887d89c13cd95f335fe44a0f792a2e6f67a52ef90e05f2e7
    [root@iZm5e0jpk0zc4zw3wn2kgbZ ~]# docker ps
    CONTAINER ID        IMAGE                  COMMAND             CREATED             STATUS              PORTS               NAMES
    a0e056122433        hoas/jdk1.8:19081902   "/bin/bash"         3 seconds ago       Up 2 seconds                            friendly_hopper
    755a7cf467b7        hoas/jdk1.8:19081902   "/bin/bash"         4 minutes ago       Up 4 minutes                            brave_clarke
    e5c600b8bd5a        hoas/jdk1.8:19081901   "/bin/bash"         4 minutes ago       Up 4 minutes                            elastic_kepler
    [root@hoas ~]# docker attach 755a7cf467b7
    root@755a7cf467b7:/# 
    root@755a7cf467b7:/#

退出方式 CTRL+P & CTRL+Q组合技能后，得到如下结果，此命令不会显示。

[root@hoas ~]# docker attach 755a7cf467b7
    root@755a7cf467b7:/# 
    root@755a7cf467b7:/# read escape sequence
    [root@hoas ~]#

> 如果不适用 docker run -it 命令启动，这种退出方式将会失效

##### 2. 通过使用exec进入容器 #####

[root@hoas ~]# docker exec -it a0e056122433 /bin/bash
    root@a0e056122433:/# javac 
    root@a0e056122433:/# java -version
    java version "1.8.0_212"
    Java(TM) SE Runtime Environment (build 1.8.0_212-b10)
    Java HotSpot(TM) 64-Bit Server VM (build 25.212-b10, mixed mode)
    root@a0e056122433:/# vi
    root@a0e056122433:/# exit
    exit
    [root@hoas ~]# docker ps

> 此时发现 exec进入容器 后 exit 容器仍然在运行中，而 attach 会导致容器关闭

##### 3. 通过使用nsenter进入容器 #####

###### 3.1 nsenter 安装 ######

[root@hoas ~]#  wget https://www.kernel.org/pub/linux/utils/util-linux/v2.24/util-linux-2.24.tar.gz
    [root@hoas ~]#  tar -xzvf util-linux-2.24.tar.gz
    [root@hoas ~]# cd util-linux-2.24/
    [root@hoas ~]# ./configure --without-ncurses
    [root@hoas ~]# make nsenter
    [root@hoas ~]# sudo cp nsenter /usr/local/bin

###### 3.2 nsenter 进入容器 ######

[root@hoas ~]# docker ps
    CONTAINER ID        IMAGE                  COMMAND             CREATED             STATUS              PORTS               NAMES
    a0e056122433        hoas/jdk1.8:19081902   "/bin/bash"         8 hours ago         Up 8 hours                              friendly_hopper
    755a7cf467b7        hoas/jdk1.8:19081902   "/bin/bash"         8 hours ago         Up 8 hours                              brave_clarke
    e5c600b8bd5a        hoas/jdk1.8:19081901   "/bin/bash"         8 hours ago         Up 8 hours                              elastic_kepler
    [root@hoas ~]# docker inspect -f {
       {.State.Pid}} a0e056122433
    2272
    [root@hoas ~]# nsenter --target 2272 --mount --uts --ipc --net --pid
    root@a0e056122433:/# ^C
    root@a0e056122433:/# exit
    logout
    [root@hoas ~]# docker ps
    CONTAINER ID        IMAGE                  COMMAND             CREATED             STATUS              PORTS               NAMES
    a0e056122433        hoas/jdk1.8:19081902   "/bin/bash"         8 hours ago         Up 8 hours                              friendly_hopper
    755a7cf467b7        hoas/jdk1.8:19081902   "/bin/bash"         8 hours ago         Up 8 hours                              brave_clarke
    e5c600b8bd5a        hoas/jdk1.8:19081901   "/bin/bash"         8 hours ago         Up 8 hours                              elastic_kepler

从执行结果可以看出 nsenter 可以通过pid的方式进入容器，且exit退出容器依然执行。

##### 4. 使用命令说明 #####

*  **docker inspect** 查看容器详细信息  
    **-f:** 指定返回值的模板文件  
    **-s:** 显示总的文件大小  
    **–type:** 为指定类型返回JSON