進入docker容器后如果退出容器，容器就會變成Exited的狀態(tài)，那么如何退出容器讓容器不關閉呢？
如果要正常退出不關閉容器，請按Ctrl+P+Q進行退出容器，這一點很重要，請牢記！
以下示例為退出容器但不關閉容器
[root@localhost ~]# docker attach c600c4519fc8
[root@c600c4519fc8 /]# exit
exit
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c600c4519fc8 centos "/bin/bash" 3 hours ago Exited (0) 1 second ago pensive_jackson
5a7a0d694651 busybox "sh" 20 hours ago Exited (0) 20 hours ago hungry_vaughan
4b0296d18849 hello-world "/hello" 46 hours ago Exited (0) 46 hours ago hopeful_yonath
[root@localhost ~]# docker start pensive_jackson
pensive_jackson
[root@localhost ~]# docker attach c600c4519fc8
Ctrl + P + Q
[root@c600c4519fc8 /]# read escape sequence
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c600c4519fc8 centos "/bin/bash" 3 hours ago Up 22 seconds pensive_jackson
5a7a0d694651 busybox "sh" 20 hours ago Exited (0) 20 hours ago hungry_vaughan
4b0296d18849 hello-world "/hello" 46 hours ago Exited (0) 46 hours ago hopeful_yonath
事實上我們可以在啟動容器的時候就進行配置，加入-d參數來啟動容器，當然，這條命令僅限于啟動全新的容器，啟動關閉的容器是不可以的。
Tips 1
docker run -d: 后臺運行容器，并返回容器ID
以下示例為使用docker -d啟動容器并退出
[root@localhost ~]# docker run -i -t -d centos /bin/bash
8521b11d5d99535d4cb0080adc5a58a4dd018ecd0751d9945f7da7ab01bec330
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
8521b11d5d99 centos "/bin/bash" 4 seconds ago Up 4 seconds eager_goldwasser
c600c4519fc8 centos "/bin/bash" 3 hours ago Exited (0) 28 seconds ago pensive_jackson
5a7a0d694651 busybox "sh" 20 hours ago Exited (0) 20 hours ago hungry_vaughan
4b0296d18849 hello-world "/hello" 46 hours ago Exited (0) 46 hours ago hopeful_yonath
[root@localhost ~]# docker attach 8
[root@8521b11d5d99 /]# uname -r
3.10.0-514.el7.x86_64
[root@8521b11d5d99 /]# exit
exit
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
8521b11d5d99 centos "/bin/bash" 2 minutes ago Exited (0) 2 seconds ago eager_goldwasser
c600c4519fc8 centos "/bin/bash" 3 hours ago Exited (0) 2 minutes ago pensive_jackson
5a7a0d694651 busybox "sh" 20 hours ago Exited (0) 20 hours ago hungry_vaughan
4b0296d18849 hello-world "/hello" 46 hours ago Exited (0) 46 hours ago hopeful_yonath
在這里你可能會發(fā)現(xiàn)，使用了-d的命令退出后容器依然還是死了，動手型的朋友可能會發(fā)現(xiàn)只是用docker run -d去啟動容器也一樣是死的
這里其實需要了解的是容器的運行機制，Docker容器在后臺運行，必須要有一個前臺進程，這里我們讓容器有前臺程序運行，就可以實現(xiàn)容器的-d 啟動后存活
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c600c4519fc8 centos "/bin/bash" 3 hours ago Exited (0) 4 minutes ago pensive_jackson
5a7a0d694651 busybox "sh" 21 hours ago Exited (0) 21 hours ago hungry_vaughan
4b0296d18849 hello-world "/hello" 47 hours ago Exited (0) 47 hours ago hopeful_yonath
[root@localhost ~]# docker run -d centos /bin/bash -c "nohup ping -i 1000 www.baidu.com"
8aa19c9604382bc019797ccda831ae1bcebd81d86380b6040d636e03000b440a
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
8aa19c960438 centos "/bin/bash -c 'nohup…" 2 seconds ago Up 2 seconds adoring_wing
c600c4519fc8 centos "/bin/bash" 3 hours ago Exited (0) 5 minutes ago pensive_jackson
5a7a0d694651 busybox "sh" 21 hours ago Exited (0) 21 hours ago hungry_vaughan
4b0296d18849 hello-world "/hello" 47 hours ago Exited (0) 47 hours ago hopeful_yonath
我這里使用nohup在后臺運行一個每1000秒ping一次百度的進程，另外你也可以使用"while true; do echo hello world; sleep 1; done"，無限輸出hello world。
另外即便是有進程在后臺運行，你進入了容器，輸入exit退出，依然會終止容器的運行，請謹記。
