docker - 多个副本放入docker swarm

Question

试图将容器部署到群中。执行命令:

 docker service create --name backend --replicas 3 --publish published=8080,target=80 my-repo/subserver:latest

它启动了3个副本，但是其中一个始终有错误:

docker service ps --no-trunc backend

    ID                          NAME                   IMAGE                            NODE                          DESIRED STATE       CURRENT STATE                  ERROR                                                 PORTS
0759ox8aganle2banj4s1uc31   backend.1       my-repo/subserver:latest   Debian-70-wheezy-64-minimal   Running             Running 2 minutes ago
zjm9tf5ca1t58iuyjsyjqpjnq   backend.2       my-repo/subserver:latest   Debian-70-wheezy-64-minimal   Running             Running 2 minutes ago
u9ebicuyh0it6kvpaj9n7id2b   backend.3       my-repo/subserver:latest   Debian-70-wheezy-64-minimal   Ready               Ready less than a second ago
4kgwlm4rddj7zefr9tc1xst75    \_ backend.3   my-repo/subserver:latest   Debian-70-wheezy-64-minimal   Shutdown            Failed 2 seconds ago           "starting container failed: Address already in use"
dqvsyy5cjd95iid845ylrpdzi    \_ backend.3   my-repo/subserver:latest   Debian-70-wheezy-64-minimal   Shutdown            Failed 8 seconds ago           "starting container failed: Address already in use"
ki0y94msyswqirm03qr7ldzl6    \_ backend.3   my-repo/subserver:latest   Debian-70-wheezy-64-minimal   Shutdown            Failed 13 seconds ago          "starting container failed: Address already in use"
emydpjqzzo5ce2ngid9ap9pb7    \_ backend.3   my-repo/subserver:latest   Debian-70-wheezy-64-minimal   Shutdown            Failed 19 seconds ago          "starting container failed: Address already in use"

尝试了不同的端口。
容器包含PHP-FPM和nginx。服务以bash脚本开头:

#!/bin/bash

service nginx start
service php7.0-fpm start

while /bin/true; do
  ps aux |grep nginx |grep -q -v grep
  PROCESS_1_STATUS=$?
  ps aux |grep php |grep -q -v grep
  PROCESS_2_STATUS=$?
  # If the greps above find anything, they will exit with 0 status
  # If they are not both 0, then something is wrong
  if [ $PROCESS_1_STATUS -ne 0 -o $PROCESS_2_STATUS -ne 0 ]; then
    echo "One of the processes has already exited."
    exit -1
  fi
  sleep 60
done

Docker文件仅公开80端口。

Answer 1

这里发生的是，您正在尝试创建都附加到同一端口的多个服务。只有单个服务可以连接到任何端口-这不是Docker特有的，在将来的技术工作中也会遇到此问题。

然而;令人好奇的是，默认情况下，“群存”模式是ingress网络为set as the default network-这是具有路由网状网络的覆盖网络；实际情况是Docker正在为您处理的第3层IP负载平衡。

所以很好奇您遇到了这个问题-我很想说您正在运行旧版本的Docker。

如果您想自己解决这个问题-最简单的方法是创建覆盖网络，例如:

docker network create --driver overlay my_new_network

然后在创建服务时，请确保指定网络:

docker service create --network my_new_network --name backend --replicas 3 --publish published=8080,target=80 my-repo/subserver:latest

这将解决基于IP的路由；但是，如果您要执行一些基于主机的路由，则可以按照@Markus的说明进行操作，并使用Traefik，Docker Flow Proxy，HAProxy等7层负载均衡器。