搭建docker swarm集群实现负载均衡

Swarm简介：

Swarm是Docker官方提供的一款集群管理工具，其主要作用是把若干台Docker主机抽象为一个整体，并且通过一个入口统一管理这些Docker主机上的各种Docker资源。
Swarm和Kubernetes比较类似，但是更加轻，具有的功能也较kubernetes更少一些

实验环境：

server1：172.25.66.1   manager
server2：172.25.66.2   node1
server3：172.25.66.3   node2

1.部署docker swarm集群

1.在物理机上制作证书

[root@foundation66 ~]# vim /etc/hosts

[root@foundation66 ~]# cd /tmp/docker/
[root@foundation66 docker]# mkdir certs
[root@foundation66 docker]# openssl req -newkey rsa:4096 -nodes -sha256 -keyout certs/domain.key -x509 -days 365 -out certs/domain.crt

[root@foundation66 docker]# cd certs/
[root@foundation66 certs]# ll
total 8
-rw-r--r--. 1 root root 2098 Mar 14 18:44 domain.crt
-rw-r--r--. 1 root root 3272 Mar 14 18:44 domain.key

[root@foundation66 certs]# cd ..
[root@foundation66 docker]# docker run -d \
> --restart=always \
> --name registry \
> -v `pwd`/certs:/certs \
> -e REGISTRY_HTTP_ADDR=0.0.0.0:443 \
> -e REGISTRY_HTTP_TLS_CERTIFICATE=/certs/domain.crt \
> -e REGISTRY_HTTP_TLS_KEY=/certs/domain.key \
> -p 443:443 \
> registry:2
Unable to find image 'registry:2' locally
2: Pulling from library/registry
Digest: sha256:3b00e5438ebd8835bcfa7bf5246445a6b57b9a50473e89c02ecc8e575be3ebb5
Status: Downloaded newer image for registry:2
21de9d97895639d9a371b4dde56ae121c36716947985589e3a9b4546d6fb5735

[root@foundation66 docker]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                            NAMES
21de9d978956        registry:2          "/entrypoint.sh /etc…"   20 seconds ago      Up 18 seconds       0.0.0.0:443->443/tcp, 5000/tcp   registry
[root@foundation66 docker]# netstat -antlp |grep :443
tcp        0      0 192.168.43.230:44402    111.7.188.1:443         ESTABLISHED 3264/firefox        
tcp6       0      0 :::443                  :::*                    LISTEN      8963/docker-proxy   
[root@foundation66 docker]# cd /etc/docker
[root@foundation66 docker]# ls
certs.d  daemon.json  key.json

2.配置主结点

（1）.下载并安装docker-engine

安装包：

docker-engine-17.05.0.ce-1.el7.centos.x86_64.rpm
docker-engine-selinux-17.05.0.ce-1.el7.centos.noarch.rpm

点击此处即可下载

[root@server1 ~]# ls
docker-engine-17.05.0.ce-1.el7.centos.x86_64.rpm
docker-engine-selinux-17.05.0.ce-1.el7.centos.noarch.rpm
[root@server1 ~]# yum install -y *
[root@sever1 ~]# yum install -y bash-*

（2）.启动docker

[root@server1 ~]# systemctl start docker
[root@sever1 ~]# netstat -antlp

（3）.初始化swarm集群

[root@server1 ~]# docker swarm init

3.配置从结点

[root@sever1 ~]# scp * [email protected]:
[root@sever1 ~]# scp * [email protected]:

在server2上：

（1）.安装docker-engine

[root@server2 ~]# ls
docker-engine-17.05.0.ce-1.el7.centos.x86_64.rpm
docker-engine-selinux-17.05.0.ce-1.el7.centos.noarch.rpm
[root@server2 ~]# yum install -y *

（2）启动docker

[root@server2 ~]# systemctl start docker

（3）.加入swarm集群

[root@server2 ~]# docker swarm join \
> --token SWMTKN-1-442o8zq8ph6h83sne03le48n2kslswc5yxrfd7tqef4vvr6dmw-d80ugn7jvlrs6b336r0zkptpe \
> 172.25.66.1:2377
This node joined a swarm as a worker.

在server3上：（操作同server2）

（1）.安装docker-engine

[root@server3 ~]# ls
docker-engine-17.05.0.ce-1.el7.centos.x86_64.rpm
docker-engine-selinux-17.05.0.ce-1.el7.centos.noarch.rpm
[root@server3 ~]# yum install -y *

（2）启动docker

[root@server3 ~]# systemctl start docker

（3）.加入warm集群

[root@server3 ~]# docker swarm join \
> --token SWMTKN-1-442o8zq8ph6h83sne03le48n2kslswc5yxrfd7tqef4vvr6dmw-d80ugn7jvlrs6b336r0zkptpe \
> 172.25.66.1:2377
This node joined a swarm as a worker.

测试：

[root@server1 ~]# docker node ls

4.传输证书

[root@foundation66 ~]# cd /etc/docker/
[root@foundation66 docker]# ls
certs.d  daemon.json  key.json
[root@foundation66 docker]# scp -r certs.d/ [email protected]:/etc/docker
[root@foundation66 docker]# scp -r certs.d/ [email protected]:/etc/docker
[root@foundation66 docker]# scp -r certs.d/ [email protected]:/etc/docker

5.添加解析

[root@server1 ~]# vim /etc/hosts

[root@server2 ~]# vim /etc/hosts

[root@server3 ~]# vim /etc/hosts

6.上传镜像

[root@foundation66 ~]# cd /etc/docker/
[root@foundation66 docker]# docker tag nginx westos.org/nginx
[root@foundation66 docker]# docker push westos.org/nginx

7.创建nginx服务

#服务数量为3，公开指定端口是8080映射容器80,使用nginx镜像
[root@server1 ~]# docker service create --name nginx --publish 80:80 --replicas 3 westos.org/nginx

#多执行几次，看到3/3就表示节点部署成功
[root@server1 ~]# docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE                     PORTS
aaw4wl9q7bvd        nginx               replicated          3/3                 westos.org/nginx:latest   *:80->80/tcp
[root@server1 ~]# docker ps
CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS               NAMES
ceace64fe731        westos.org/nginx:latest   "nginx -g 'daemon ..."   9 minutes ago       Up 8 minutes        80/tcp              nginx.1.ijwxybakh8iuzz5hu6hf2m0ma
[root@server1 ~]# docker service ps nginx
ID                  NAME                IMAGE                     NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS
ijwxybakh8iu        nginx.1             westos.org/nginx:latest   server1             Running             Running 9 minutes ago                       
rol3e3dh55eh        nginx.2             westos.org/nginx:latest   server2             Running             Running 9 minutes ago                       
xghzsv46okz1        nginx.3             westos.org/nginx:latest   server3             Running             Running 9 minutes ago                       

#添加3个nginx服务
[root@server1 ~]# docker service scale nginx=3
nginx scaled to 3
[root@server1 ~]# docker service ps nginx
ID                  NAME                IMAGE                     NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS
ijwxybakh8iu        nginx.1             westos.org/nginx:latest   server1             Running             Running 12 minutes ago                       
rol3e3dh55eh        nginx.2             westos.org/nginx:latest   server2             Running             Running 12 minutes ago                       
xghzsv46okz1        nginx.3             westos.org/nginx:latest   server3             Running             Running 12 minutes ago     
#发现每个结点均分一个nginx服务                
[root@server1 ~]# docker ps
CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS               NAMES
ceace64fe731        westos.org/nginx:latest   "nginx -g 'daemon ..."   12 minutes ago      Up 12 minutes       80/tcp              nginx.1.ijwxybakh8iuzz5hu6hf2m0ma
[root@server2 ~]# docker ps
CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS               NAMES
48385ae882d3        westos.org/nginx:latest   "nginx -g 'daemon ..."   12 minutes ago      Up 12 minutes       80/tcp              nginx.2.rol3e3dh55eh1ox9wmv430ydy
[root@server3 ~]# docker ps
CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS               NAMES
42ca62659a89        westos.org/nginx:latest   "nginx -g 'daemon ..."   12 minutes ago      Up 12 minutes       80/tcp              nginx.3.xghzsv46okz1l2b1yvullo90w

注意：如果nginx服务创建错误，执行以下命令即可删除，再重新创建即可

[root@sever1 ~]#  docker service rm nginx
nginx

测试：

无论输入3个节点的ip均可以看到nginx默认发布首页

2.集群负载均衡

1.拉取镜像

[root@foundation66 Desktop]# docker pull docker.io/dockersamples/visualizer

2.上传镜像

#更改名称
[root@foundation66 Desktop]# docker tag dockersamples/visualizer westos.org/visualizer
#上传镜像
[root@foundation66 Desktop]# docker push westos.org/visualizer

3.创建visualizer服务

[root@server1 ~]# docker service create \
> --name=viz \
> --publish=8080:8080/tcp \
> --constraint=node.role==manager \
> --mount=type=bind,src=/var/run/docker.sock,dst=/var/run/docker.sock \
> westos.org/visualizer
8lxnuxxt8ayuaifk04209nd7m
Since --detach=false was not specified, tasks will be created in the background.
In a future release, --detach=false will become the default.

#多执行几次，直到查看到REPLICAS变为1/1
[root@server1 ~]# docker service ls

4.编写发布页面

在server1上：

#1.编写文件
[root@server1 docker]# echo server1 > index.html
[root@server1 ~]# cat index.html 
server1
#2.拷贝文件
[root@server1 ~]# docker ps
[root@server1 ~]# docker container cp index.html nginx.2.ykxkni9lxcy306jtyyr089e9u:/usr/share/nginx/html

在server2上：

[root@server2 ~]# echo server2 > index.html
[root@sever2 ~]# cat index.html 
server2
[root@server2 ~]# docker ps
[root@server2 ~]# docker container cp index.html nginx.3.tcitff6ljd980kzua8os540lq:/usr/share/nginx/html

在server3上：

[root@server3 ~]# echo server3 > index.html
[root@server3 ~]# cat index.html 
server3
[root@server3 ~]# docker ps
[root@server3 ~]# docker container cp index.html nginx.1.vc2goxg1rjxchn2mbyfvntqqw:/usr/share/nginx/html

测试：

#利用for循环，访问10次。发现server1和server2和server3交替，说明负载均衡搭建成功
[root@foundation66 ~]# for i in {1..10}; do curl 172.25.66.1;done

在网页上输入：172.25.66.1:8080

模拟server3结点宕机

[root@server3 ~]# systemctl stop docker

刷新网页：