确保给定的docker容器正在运行 [英] making sure a given docker container is running

问题描述

我现在在很多服务器上使用码头服务器，但有时候由于重负载，我使用了一些容器。我正在考虑添加一个cron，检查容器运行的每一分钟，但是我没有找到任何令人满意的方法。

我开始该容器具有保存正在运行的容器的id的cidfile。如果容器崩溃，cidfile保持在内部的id，我只是想知道你们如何确保容器运行或不运行，并重新启动它，以防万一它下降。我应该解析 docker ps -a 的输出，还是有更优雅的解决方案？

解决方案

答案有些埋葬深度，但我发现了以最优雅为由的多种方式：

1. 命名您的容器运行它，以便您可以附加到它的进程记录，并与过程监视器，如upstart / systemd / supervisord

   
   
   

   docker run -itd -name = test ubuntu

   
   
   

   upstart示例（ / etc / init / test） conf ）：

   
   
   

   描述我的测试容器
在文件系统上启动并启动docker
停在运行级别[！2345]
respawn
script
/ usr / bin / docker start -a test
end script
/ p>




2. 不太优雅：注意更改cidfile内容

   
   
   

   docker run - itd --name = test --cidfile = / tmp / cidfile_path ubuntu

   
   
   

   urly cron可能...

    ＃！/ bin / bash 
    
    RUNNING = $（docker ps -a --no-trunc | awk'/ test /&& / Up /'| awk'{print $ 1}'）
    CIDFILE = $（cat / tmp / cidfile_path）
    
   如果[$ RUNNING！=$ CIDFILE] 
   然后
   ＃做某事聪明
    fi 
     




3. 与上述类似，你可以看到如果给定的容器正在运行...在循环/ cron /无论什么

    ＃！/ bin / bash 
    RUNNING = $（docker inspect --format'{{.State.Running}}'test）
    
   如果[$ RUNNING== false] 
   然后
   ＃一些聪明的
    fi 
     

你可以结合命令来做任何你喜欢的检查脚本，我去了 upstart ，因为它适合我的情况，但是如果你需要更多的控制，这些例子可以用于所有可能的情况。 p>

I'm using docker on quite a lot of servers right now but sometimes some of the containers I use crash due to heavy load. I was thinking on adding a cron that checks every minute of the container is running or not but I didn't find any satisfactory method on doing that.

I'm starting the container with a cidfile that saves the id of the running container. If the container crashes the cidfile stays there with the id inside and I was just wondering how do you guys make sure a container is running or not and respawn it in case it went down. Should I just parse the output of docker ps -a or is there more elegant solution?

解决方案

The answer is somewhat buried levels deep but I found out multiple ways of doing it starting with the most elegant:

1. Name your container when running it so you can attach to it's process logging and couple that with a process monitor such as upstart/systemd/supervisord

   docker run -itd --name=test ubuntu

   upstart example (/etc/init/test.conf):

   description "My test container" start on filesystem and started docker stop on runlevel [!2345] respawn script /usr/bin/docker start -a test end script

2. Less elegant: watch for changes in cidfile contents

   docker run -itd --name=test --cidfile=/tmp/cidfile_path ubuntu

   An hourly cron maybe...

   #!/bin/bash
   
   RUNNING=$(docker ps -a --no-trunc | awk '/test/ && /Up/' | awk '{print $1}')
   CIDFILE=$(cat /tmp/cidfile_path)
   
   if [ "$RUNNING" != "$CIDFILE" ]
   then
      # do something wise
   fi
   

3. Similar to the above you can see if a given container is running...in a loop/cron/whatever

   #!/bin/bash
   RUNNING=$(docker inspect --format '{{.State.Running}}' test)
   
   if [ "$RUNNING" == false ]
   then
      # do something wise
   fi
   

You can combine commands to do whatever checking script you like, I went with upstart because it suits my situation but these examples could be used for all possible scenarios should you need more control.

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