docker run -d和docker run -it的区别详解

docker run -it

i : interactive 代表交互
-t : tty 分配伪 TTY

测试不带前台进程的，例如centos/ubuntu

> docker run -it ubuntu
root@a30a87e0e065:/# exit
exit
> docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

我们发现容器已经退出了

> docker run -it ubuntu
root@a30a87e0e065:/# 输入Ctrl + P + Q
> docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e51e423ac575 ubuntu \”bash\” 10 seconds ago Up 10 seconds romantic_franklin

发现容器不会退出

测试带前台进程的，例如redis

> docker run -it redis
1:C 26 Nov 2022 15:15:37.357 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
1:C 26 Nov 2022 15:15:37.357 # Redis version=6.2.6, bits=64, commit=00000000, modified=0, pid=1, just started
a config file use redis-server /path/to/redis.conf
1:M 26 Nov 2022 15:15:37.358 * monotonic clock: POSIX clock_gettime
_._
_.-“__ \’\’-._
_.-“ `. `_. \’\’-._ Redis 6.2.6 (00000000/0) 64 bit
( \’ , .-` | `, ) Running in standalone mode
|`-._`-…-` __…-.“-._|\’` _.-\’| Port: 6379
| `-._ `._ / _.-\’ | PID: 1
`-._ `-._ `-./ _.-\’ _.-\’
|`-._`-._ `-.__.-\’ _.-\’_.-\’|
| `-._`-._ _.-\’_.-\’ | https://redis.io
`-._ `-._`-.__.-\’_.-\’ _.-\’
|`-._`-._ `-.__.-\’ _.-\’_.-\’|
| `-._`-._ _.-\’_.-\’ |
`-._ `-._`-.__.-\’_.-\’ _.-\’
`-._ `-.__.-\’ _.-\’
`-._ _.-\’
`-.__.-\’

1:M 26 Nov 2022 15:15:37.358 # Server initialized
1:M 26 Nov 2022 15:15:37.358 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add \’vm.overcommit_memory = 1\’ to /etc/sysctl.conf and then reboot or run the command \’sysctl vm.overcommit_memory=1\’ for this to take effect.
1:M 26 Nov 2022 15:15:37.358 * Ready to accept connections

# 输入Ctrl + P + Q
> docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
14cef5be594b redis \”docker-entrypoint.s…\” 15 seconds ago Up 14 seconds 6379/tcp silly_wright

> docker run -it redis
1:C 26 Nov 2022 15:22:49.890 # Redis version=6.2.6, bits=64, commit=00000000, modified=0, pid=1, just started
1:C 26 Nov 2022 15:22:49.890 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
1:M 26 Nov 2022 15:22:49.891 * monotonic clock: POSIX clock_gettime
_._
_.-“__ \’\’-._
_.-“ `. `_. \’\’-._ Redis 6.2.6 (00000000/0) 64 bit
.-“ .-“`. “`\\/ _.,_ \’\’-._
( \’ , .-` | `, ) Running in standalone mode
|`-._`-…-` __…-.“-._|\’` _.-\’| Port: 6379
| `-._ `._ / _.-\’ | PID: 1
`-._ `-._ `-./ _.-\’ _.-\’
|`-._`-._ `-.__.-\’ _.-\’_.-\’|
| `-._`-._ _.-\’_.-\’ | https://redis.io
`-._ `-._`-.__.-\’_.-\’ _.-\’
|`-._`-._ `-.__.-\’ _.-\’_.-\’|
| `-._`-._ _.-\’_.-\’ |
`-._ `-._`-.__.-\’_.-\’ _.-\’
`-._ `-.__.-\’ _.-\’
`-._ _.-\’
`-.__.-\’

1:M 26 Nov 2022 15:22:49.891 # Server initialized
1:M 26 Nov 2022 15:22:49.891 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add \’vm.overcommit_memory = 1\’ to /etc/sysctl.conf and then reboot or run the command \’sysctl vm.overcommit_memory=1\’ for this to take effect.
1:M 26 Nov 2022 15:22:49.891 * Ready to accept connections
exit #这里没有反应，我们继续Ctrl + C
^C1:signal-handler (1669476186) Received SIGINT scheduling shutdown…
1:M 26 Nov 2022 15:23:06.123 # User requested shutdown…
1:M 26 Nov 2022 15:23:06.123 * Saving the final RDB snapshot before exiting.
1:M 26 Nov 2022 15:23:06.130 * DB saved on disk
1:M 26 Nov 2022 15:23:06.130 # Redis is now ready to exit, bye bye…
> docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
8668b2bf13b1 redis \”docker-entrypoint.s…\” 24 seconds ago Exited (0) 7 seconds ago ecstatic_lehmann

总结：

-it 使用交互方式运行，进入容器查看内容

1.当运行的镜像没有前台进程。

exit #run进去容器，exit退出，容器停止

Ctrl+P+Q # run进去容器，ctrl+p+q退出，容器不停止

1.当运行的镜像有前台进程。

exit #用exit无效，使用Ctrl + C ,容器会停止

Ctrl+P+Q # run进去容器，ctrl+p+q退出，容器不停止

docker run -d

-d : detach 表示后台运行

测试不带前台进程的，例如centos/ubuntu

> docker run -d ubuntu
> docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
0210648ee10f ubuntu \”bash\” 34 seconds ago Exited (0) 32 seconds ago jolly_wright

我们发现容器启动后会立马退出

测试带前台进程的，例如redis

> docker run -d redis
> docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
3adf2698b224 redis \”docker-entrypoint.s…\” 5 seconds ago Up 4 seconds 6379/tcp vigilant_agnesi

我们发现容器不会退出

总结：

Docker容器后台运行,就必须有一个前台进程.

容器运行的命令如果不是那些一直挂起的命令（比如运行top，tail），就是会自动退出的。

docker run -d ubuntu tail -f /dev/null # 这种情况就不会退出了