How do you attach and detach from Docker's pro

问题:

I can attach to a docker process but Ctrl+c doesn't work to detach from it. exit basically halts the process.

What's the recommended workflow to have the process running, occasionally attaching to it to make some changes, and then detaching?

回答1:

To detach the tty without exiting the shell, use the escape sequence Ctrl+p + Ctrl+q.

more details here: https://docs.docker.com/engine/reference/commandline/attach/

回答2:

Check out also the --sig-proxy option:

docker attach --sig-proxy=false 304f5db405ec

Then use CTRL+c to detach

回答3:

If you just want to make some modification to files or inspect processes, here's one another solution you probably want.

You could run the following command to execute a new process from the existing container:

sudo docker exec -ti [CONTAINER-ID] bash

will start a new process with bash shell, and you could escape from it by ^c directly, it won't affect the original process.

回答4:

I think this should depend on the situation.Take the following container as an example:

# docker run -it -d ubuntu
91262536f7c9a3060641448120bda7af5ca812b0beb8f3c9fe72811a61db07fc
# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
91262536f7c9        ubuntu              "/bin/bash"         5 seconds ago       Up 4 seconds                            serene_goldstine

(1) Use "docker attach" to attach the container:

Since "docker attach" will not allocate a new tty, but reuse the original running tty, so if you run exit command, it will cause the running container exit:

# docker attach 91262536f7c9
exit
exit
# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                     PORTS               NAMES
91262536f7c9        ubuntu              "/bin/bash"         39 minutes ago      Exited (0) 3 seconds ago                       serene_goldstine

So unless you really want to make running container exit, you should use Ctrl+p + Ctrl+q.

(2) Use "docker exec"

Since "docker exec" will allocate a new tty, so I think you should use exit instead of Ctrl+p + Ctrl+q.

The following is executing Ctrl+p + Ctrl+q to quit the container:

# docker exec -it 91262536f7c9 bash
root@91262536f7c9:/# ps -aux
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0  18160  1908 ?        Ss+  04:03   0:00 /bin/bash
root        15  0.0  0.0  18164  1892 ?        Ss   04:03   0:00 bash
root        28  0.0  0.0  15564  1148 ?        R+   04:03   0:00 ps -aux
root@91262536f7c9:/# echo $$
15

Then login container again, you will see the bash process in preavious docker exec command is still alive (PID is 15):

# docker exec -it 91262536f7c9 bash
root@91262536f7c9:/# ps -aux
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0  18160  1908 ?        Ss+  04:03   0:00 /bin/bash
root        15  0.0  0.0  18164  1892 ?        Ss+  04:03   0:00 bash
root        29  0.0  0.0  18164  1888 ?        Ss   04:04   0:00 bash
root        42  0.0  0.0  15564  1148 ?        R+   04:04   0:00 ps -aux
root@91262536f7c9:/# echo $$
29

回答5:

when nothing else works, open a new terminal then:

$ ps aux | grep attach
username  <pid_here>    ..............  0:00 docker attach <CONTAINER_HASH_HERE>
username  <another_pid> ..............  0:00 grep --color=auto attach
$ kill -9 <pid_here>

回答6:

To detach from a running container, use ^P^Q (hold the Ctrl, press P, press Q, release Ctrl).

There's a catch: this only works if the container was started with both -t and -i.

If you have a running container that was started without one (or both) of these options, and you attach with docker attach, you'll need to find another way to detach. Depending on the options you chose and the program that's running, ^C may work, or it may kill the whole container. You'll have to experiment.

Another catch: Depending on the programs you're using, your terminal, shell, SSH client, or multiplexer could be intercepting either ^P or ^Q (usually the latter). To test whether this is the issue, try running or attaching with the --detach-keys z argument. You should now be able to detach by pressing z, without any modifiers. If this works, another program is interfering. The easiest way to work around this is to set your own detach sequence using the --detach-keys argument. (For example, to exit with ^K, use --detach-keys 'ctrl-k'.) Alternatively, you can attempt to disable interception of the keys in your terminal or other interfering program. For example, stty start '' or stty start undef may prevent the terminal from intercepting ^Q on some POSIX systems, though I haven't found this to be helpful.

回答7:

I had the same issue, ctrl-P and Q would not work, nor ctrl-C... eventually I opened another terminal session and I did "docker stop containerid " and "docker start containerid " and it got the job done. Weird.

回答8:

To detach from the container you simply hold Ctrl and press P + Q.

To attach to a running container you use:

$ docker container attach "container_name"

回答9:

In the same shell, hold ctrl key and press keys p then q

回答10:

to stop a docker process and release the ports, first use ctrl-c to leave the exit the container then use docker ps to find the list of running containers. Then you can use the docker container stop to stop that process and release its ports. The container name you can find from the docker ps command which gives the name in the name column. Hope this solves your queries....