如何向docker容器中运行的程序发送信号？

I have a program run in a docker container with detached mode.

我有一个程序在一个具有分离模式的docker容器中运行。

So how to send a signal such as SIGINT to this program?

那么如何向这个程序发送SIGINT等信号呢？

4 个解决方案

#1

You can use nsenter to get into your container space and send your signal.

您可以使用nsenter进入容器空间并发送信号。

PID=$(docker inspect --format {{.State.Pid}} <container_name_or_ID>)
nsenter --target $PID --mount --uts --ipc --net --pid kill -SIGINT <PID of your program inside your container>

More info : http://jpetazzo.github.io/2014/06/23/docker-ssh-considered-evil/

更多信息：http：//jpetazzo.github.io/2014/06/23/docker-ssh-considered-evil/

#2

You can use docker kill --signal="<signal>" <container name or id> to send any signal to the root process of a given container.

您可以使用docker kill --signal =“ ” <容器名称或id> 将任何信号发送到给定容器的根进程。

See http://docs.docker.com/engine/reference/commandline/kill/

见http://docs.docker.com/engine/reference/commandline/kill/

#3

docker kill used to send signal to main container process i.e process with PID 1.
docker kill用于向主容器进程发送信号，即使用PID 1进行处理。
Any application with PID 1 can handle signals directly. Below command kill the main docker process: $ docker kill --signal="SIGTERM" container-id/name
PID 1的任何应用都可以直接处理信号。下面的命令会杀死主要的docker进程：$ docker kill --signal =“SIGTERM”container-id / name
But application which does not have PID 1 i.e application is background process:
- We can not send single directly to any background process running within docker container.
- 我们无法直接将单个发送到docker容器中运行的任何后台进程。
- In this case we need to trap and handle the user defined signal in the shell script running as entry point.
- 在这种情况下，我们需要在作为入口点运行的shell脚本中捕获和处理用户定义的信号。
但是没有PID 1即应用程序的应用程序是后台进程：我们不能直接向docker容器内运行的任何后台进程发送单个。在这种情况下，我们需要在作为入口点运行的shell脚本中捕获和处理用户定义的信号。
Let's we have the following Dockerfile. (Update it as per the application)
我们有以下Dockerfile。（根据应用程序更新）

FROM centos:6.7
# Install/Deploye the service below.

# Copy the shell script.
COPY entrypoint.sh /home
EXPOSE 8080
ENTRYPOINT ["/home/entrypoint.sh"]

Below is the entrypoint.sh. (Update it it as per the application). Suppose we wants to restart a init.d service.

以下是entrypoint.sh。（根据应用程序更新它）。假设我们要重启init.d服务。

#start the service
/etc/init.d/<servicename> start
pid="$!"

# SIGUSR1- Single handler
my_handler() {
    /etc/init.d/<servicename> restart
}

# Trap and handle the user defind singnal.
trap 'my_handler' SIGUSR1

# wait forever(Alive container.)
while true
do
    tail -f /dev/null & wait ${!}
done

Build the docker image and run the container.
构建docker镜像并运行容器。
Now you can restart the service from Host machine: $docker kill --signal="SIGUSR1" container-id/name
现在您可以从主机重启服务：$ docker kill --signal =“SIGUSR1”container-id / name

#4

I managed to send a signal I want to a process(program) in docker container by:

我设法通过以下方式向docker容器中的进程（程序）发送我想要的信号：

Getting the ID of the container - docker ps | grep yourProgramName - for me it looks like so - 4b6425cf4261
获取容器的ID - docker ps | grep yourProgramName - 对我来说看起来像是这样 - 4b6425cf4261
Login into the container using docker exec -it 4b6425cf4261 bash
使用docker exec -it 4b6425cf4261 bash登录容器
List all the running processes with ps -A
使用ps -A列出所有正在运行的进程
Find the PID of the process you want to send a SIGINT to
找到要将SIGINT发送到的进程的PID
Send the signal to it: kill -SIGINT PID (example: kill -SIGINT 15)
发送信号给它：kill -SIGINT PID（例如：kill -SIGINT 15）

#1