Centos7 Docker 集群实验（实验篇）

编写Dockerfile

1. 使用PHPStorm Docker插件编写Dockerfile

Docker 服务开启远程连接功能

vim /usr/lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock -H tcp://0.0.0.0:2375
systemctl daemon-reload
systemctl restart docker

2.nginx php-fpm dockerfile

#Execute: docker run -d --rm --privileged -p 80:80 php72-yaf:v1
FROM centos
LABEL maintainer="[email protected]"
ENV PHP_BIN /opt/remi/php72/root/usr/bin
WORKDIR /workspace/software/
ADD ./yaf-3.0.8.tgz ./
RUN rpm -Uvh http://nginx.org/packages/centos/7/noarch/RPMS/nginx-release-centos-7-0.el7.ngx.noarch.rpm && \
    yum install -y nginx && \
    yum install -y epel-release && \
    yum install -y yum-utils && \
    yum install -y http://rpms.remirepo.net/enterprise/remi-release-7.rpm && \
    yum-config-manager --enable remi-php72 && \
    yum -y update && \
    yum install -y php72 && \
    yum install -y php72-php-fpm php72-php-gd php72-php-json php72-php-mbstring php72-php-mysqlnd php72-php-xml php72-php-xmlrpc php72-php-opcache php72-php-pecl-redis5 \
        php72-php-bcmath php72-php-devel && \
    cd /workspace/software/yaf-3.0.8 && \
    $PHP_BIN/phpize && \
    ./configure --with-php-config=$PHP_BIN/php-config && \
    make && \
    make install && \
    systemctl enable php72-php-fpm && \
    systemctl enable nginx
EXPOSE 80
CMD ["/usr/sbin/init"] #因为php-fpm及nginx都是以后台服务运行因此需要执行此指令

---

ps:期间采用增加 entrypoint.sh的方式 即:

ENTRYPOINT ["./entrypoint.sh"]

entrypoint.sh的内容为:

#!/usr/bin/env bash
set -e  #执行中任何语句出错，中止

/usr/sbin/init

exec "$@" #执行后面的指令

运行报错:Couldn't find an alternative telinit implementation to spawn.
需要使用 exec /usr/sbin/init

---

2.1 ENTRYPOINT CMD使用说明:

	No ENTRYPOINT	ENTRYPOINT exec_entry p1_entry	ENTRYPOINT [“exec_entry”, “p1_entry”]
No CMD	error, not allowed	/bin/sh -c exec_entry p1_entry	exec_entry p1_entry
CMD [“exec_cmd”, “p1_cmd”]	exec_cmd p1_cmd	/bin/sh -c exec_entry p1_entry	exec_entry p1_entry exec_cmd p1_cmd
CMD [“p1_cmd”, “p2_cmd”]	p1_cmd p2_cmd	/bin/sh -c exec_entry p1_entry	exec_entry p1_entry p1_cmd p2_cmd
CMD exec_cmd p1_cmd	/bin/sh -c exec_cmd p1_cmd	/bin/sh -c exec_entry p1_entry	exec_entry p1_entry /bin/sh -c exec_cmd p1_cmd

3.集群部署

3.1 初始化swarm集群

在192.168.101.252 运行指令:

docker-machine ssh Node1 "docker swarm init --advertise-addr 192.168.101.253"

结果如下:

Swarm initialized: current node (8byxvzemg17dlsq1zt199y2e3) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-3c2gclwswbpfynj3jv46beuth4kq95so3ljyodzjqvhim9cqgd-2qhqn9bw51b3sm6wo947o9cut 192.168.101.253:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

执行:

docker-machine ssh Node2 "docker swarm join --token SWMTKN-1-3c2gclwswbpfynj3jv46beuth4kq95so3ljyodzjqvhim9cqgd-2qhqn9bw51b3sm6wo947o9cut 192.168.101.253:2377"

在Manager上运行“docker node ls”来查看节点

[root@192 ~]# docker-machine ssh Node1 "docker node ls"
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
8byxvzemg17dlsq1zt199y2e3 *   Node1               Ready               Active              Leader              19.03.1
66vjclco8d9twjk3w1y0lz82h     Node2               Ready               Active                                  19.03.1

3.2 部署nginx,php-fpm到集群上

在192.168.101.252 运行指令:

eval $(docker-machine env Node1)

docker-machine ls

显示如下结果:

NAME    ACTIVE   DRIVER    STATE     URL                        SWARM   DOCKER     ERRORS
Node1   *        generic   Running   tcp://192.168.101.253:2376           v19.03.1   
Node2   -        generic   Running   tcp://192.168.101.254:2376           v19.03.1   

部署服务,运行指令:

docker stack deploy -c docker-compose.yml php72yaf

ps:使用的docker-compose.yml文件如下:

version: "3"
services:
  web:
    image: nginx
    deploy:
      replicas: 3
      resources:
        limits:
          cpus: "0.2"
      restart_policy:
        condition: on-failure
    ports:
      - "80:80"
    networks:
      - webnet
networks:
  webnet:

运行指令:

docker stack ps php72yaf

查看各节点上的容器部署情况

ID                  NAME                IMAGE                                 NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS
34ji2447cjxh        php72yaf_web.1      nginx:latest   Node2               Running             Running 29 minutes ago                       
77kaoz565uif        php72yaf_web.2      nginx:latest   Node1               Running             Running 29 minutes ago                       
orxdvbxe9gj1        php72yaf_web.3      nginx:latest   Node1               Running             Running 29 minutes ago                       

访问集群:
此时请求 http://192.168.101.253或http://192.168.101.254
都可以访问到nginx服务

ps:本篇在实验过程中想使用第二节中所写的dockerfile来构建自定义镜像，但是因为需要privileged权限，而swarm集群不支持此选项，所以在docker-compose.yml中使用了官方的nginx镜像进行了集群实验。因此本篇的第二、三节内容有点脱节，第二节dockerfile产生的镜像适用于单独运行，第三节仅是集群的一个演示，下一篇会讲php-fpm与nginx进行分拆，重新部署在集群中。