详解使用docker 1.12 搭建多主机docker swarm集群

swarm是docker公司自己的容器集群管理工具，本文介绍了使用docker 1.12 搭建多主机docker swarm集群，分享给大家

准备

准备至少两台的centos 7 主机(全新最小安装, 可以使用虚拟机安装)
开放端口2377 tcp端口, 7946 4789 tcp udp 端口
本文使用192.168.99.101(hostname:centos-node4) 作为swarm manager
192.168.99.102(hostname:centos-node5) 作为swarm agent1

安装docker engine 1.12
在每台机器上执行以下命令

# sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository 
baseurl=https://yum.dockerproject.org/repo/main/centos/7/ 
enabled=1 
gpgcheck=1 
gpgkey=https://yum.dockerproject.org/gpg 
EOF

# sudo yum install docker-engine
# sudo systemctl enable docker
# sudo systemctl start docker

安装完后查看Docker 版本

[root@centos-node4 ~]# docker version 
Client: 
 Version:   1.12.0
 API version: 1.24
 Go version:  go1.6.3
 Git commit:  8eab29e
 Built:    
 OS/Arch:   linux/amd64

Server: 
 Version:   1.12.0
 API version: 1.24
 Go version:  go1.6.3
 Git commit:  8eab29e
 Built:    
 OS/Arch:   linux/amd64

开放端口相关命令

firewall-cmd --zone=public --add-port=2377/tcp --permanent 
firewall-cmd --zone=public --add-port=7946/tcp --permanent 
firewall-cmd --zone=public --add-port=7946/udp --permanent 
firewall-cmd --zone=public --add-port=4789/tcp --permanent 
firewall-cmd --zone=public --add-port=4789/udp --permanent 
firewall-cmd --reload

新版docker swarm 命令详情

有关集群的docker命令如下：

docker swarm：集群管理，子命令有init, join,join-token, leave, update
docker node：节点管理，子命令有demote, inspect,ls, promote, rm, ps, update
docker service：服务管理，子命令有create, inspect, ps, ls ,rm , scale, update
docker stack/deploy：试验特性，用于多应用部署

创建swarm 集群

查看docker swarm 命令说明

[root@centos-node4 ~]# docker swarm -h
Flag shorthand -h has been deprecated, please use --help

Usage:  docker swarm COMMAND

Manage Docker Swarm

Options: 
   --help  Print usage

Commands: 
 init    Initialize a swarm
 join    Join a swarm as a node and/or manager
 join-token Manage join tokens
 update   Update the swarm
 leave    Leave a swarm

Run 'docker swarm COMMAND --help' for more information on a command.

在swarm manager(centos-node4:192.168.99.101)初始化swarm集群

用--listen-addr指定监听的ip与端口

#命令格式: docker swarm init --listen-addr <MANAGER-IP>:<PORT>
[root@centos-node4 ~]# docker swarm init --listen-addr 192.168.99.101:2377
Swarm initialized: current node (a60d5c3ttymvtozr46uvk17q4) is now a manager.

查看结果

[root@centos-node4 ~]# docker node ls
ID              HOSTNAME   MEMBERSHIP STATUS AVAILABILITY MANAGER STATUS 
a60d5c3ttymvtozr46uvk17q4 * centos-node4 Accepted  Ready  Active    Leader

把swarm-agent1(centos-node5: 192.168.99.102)添加到swarm集群

在swarm-agent1上执行:

#命令格式: docker swarm join <MANAGER-IP>:<PORT>
[root@centos-node5 ~]# docker swarm join 192.168.99.101:2377
This node joined a Swarm as a worker.

在swarm manager查看结果

[root@centos-node4 ~]# docker node ls
ID              HOSTNAME   MEMBERSHIP STATUS AVAILABILITY MANAGER STATUS 
0ypcw58hjlcvr0xqbtizmau62  centos-node5 Accepted  Ready  Active 
a60d5c3ttymvtozr46uvk17q4 * centos-node4 Accepted  Ready  Active    Leader

创建一个overlay 跨主机网络

查看原有网络

[root@centos-node4 ~]# docker network ls
NETWORK ID     NAME        DRIVER       SCOPE 
abec77415f48    bridge       bridge       local 
e2fff9d572a6    docker_gwbridge   bridge       local 
166bd71f7d0e    host        host        local 
9gr6bfff1rv9    ingress       overlay       swarm 
1d2bfc590294    none        null        local

可以看到在swarm上默认已有一个名为ingress的overlay 网络,默认在swarm里使用，本文会创建一个新的

创建一个新的overlay网络

 [root@centos-node4 ~]# docker network create --driver overlay docker-net
aoqs3p835s5glx69hi46ou2dw 
 [root@centos-node4 ~]# docker network ls
NETWORK ID     NAME        DRIVER       SCOPE 
abec77415f48    bridge       bridge       local 
aoqs3p835s5g    docker-net     overlay       swarm 
e2fff9d572a6    docker_gwbridge   bridge       local 
166bd71f7d0e    host        host        local 
9gr6bfff1rv9    ingress       overlay       swarm 
1d2bfc590294    none        null        local

新的网络(docker-net)已创建

在新的跨主机overlay 网络(docker-net)上创建应用

部署

用alpine镜像在docker-net网络上启动两个实例, 并编排为一组服务

[root@centos-node4 ~]# docker service create --replicas 2 --name helloworld --network=docker-net alpine ping docker.com
5lgdq3ihiez0o7h2uegu4fgd3

查看部署结果

[root@centos-node4 ~]# docker service ls
ID      NAME    REPLICAS IMAGE  COMMAND 
5lgdq3ihiez0 helloworld 0/2    alpine ping docker.com 
[root@centos-node4 ~]# docker service tasks helloworld
ID             NAME     SERVICE   IMAGE  LAST STATE     DESIRED STATE NODE 
eul3bus45qz3b555wekotdmo5 helloworld.1 helloworld alpine Running 14 seconds Running    centos-node5 
55uhq6xxcv53xlkqv2f0be9b9 helloworld.2 helloworld alpine Running 14 seconds Running    centos-node4

可以看到两个实例分别运行在两个节点上

测试两个主机的网络是否能互通

分别查看两个实例的名称

# 在swarm-manager 上执行
[root@centos-node4 ~]# docker ps -a
CONTAINER ID    IMAGE        COMMAND         CREATED       STATUS          PORTS        NAMES 
f4a197abdb0b    alpine:latest    "ping docker.com"    42 minutes ago   Up 42 minutes                 helloworld.2.55uhq6xxcv53xlkqv2f0be9b9

# 在swarm-agnet1 上执行
[root@centos-node5 ~]# docker ps -a
CONTAINER ID    IMAGE        COMMAND       CREATED       STATUS       PORTS        NAMES 
39cc35cd54b5    alpine:latest    "ping docker.com"  50 seconds ago   Up 49 seconds              helloworld.1.eul3bus45qz3b555wekotdmo5

在swarm-manager 上测试

[root@centos-node4 ~]# docker exec -ti helloworld.2.55uhq6xxcv53xlkqv2f0be9b9 sh
/ # ping helloworld.1.eul3bus45qz3b555wekotdmo5
PING helloworld.1.eul3bus45qz3b555wekotdmo5 (10.0.9.3): 56 data bytes 
64 bytes from 10.0.9.3: seq=0 ttl=64 time=0.514 ms 
64 bytes from 10.0.9.3: seq=1 ttl=64 time=0.508 ms 
64 bytes from 10.0.9.3: seq=2 ttl=64 time=0.381 ms 
64 bytes from 10.0.9.3: seq=3 ttl=64 time=0.408 ms 
^C
--- helloworld.1.eul3bus45qz3b555wekotdmo5 ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss 
round-trip min/avg/max = 0.381/0.452/0.514 ms

在swarm-agent1 上测试

[root@centos-node5 ~]# docker ps -a
CONTAINER ID    IMAGE        COMMAND       CREATED       STATUS       PORTS        NAMES 
39cc35cd54b5    alpine:latest    "ping docker.com"  50 seconds ago   Up 49 seconds              helloworld.1.eul3bus45qz3b555wekotdmo5 
[root@centos-node5 ~]# docker exec -ti helloworld.1.eul3bus45qz3b555wekotdmo5 sh
/ # ping helloworld.2.55uhq6xxcv53xlkqv2f0be9b9
PING helloworld.2.55uhq6xxcv53xlkqv2f0be9b9 (10.0.9.4): 56 data bytes 
64 bytes from 10.0.9.4: seq=0 ttl=64 time=0.892 ms 
64 bytes from 10.0.9.4: seq=1 ttl=64 time=0.463 ms 
64 bytes from 10.0.9.4: seq=2 ttl=64 time=0.462 ms 
64 bytes from 10.0.9.4: seq=3 ttl=64 time=0.478 ms 
64 bytes from 10.0.9.4: seq=4 ttl=64 time=0.468 ms 
64 bytes from 10.0.9.4: seq=5 ttl=64 time=0.459 ms 
^C
--- helloworld.2.55uhq6xxcv53xlkqv2f0be9b9 ping statistics ---
6 packets transmitted, 6 packets received, 0% packet loss 
round-trip min/avg/max = 0.459/0.537/0.892 ms

现在新版的docker swarm 管理非常简单, 可以快速的搭建起一个跨主机的集群并部署应用

dokcer swarm自带的负载均衡

创建一组服务

docker service create --replicas 2 --name whoami -p 8080:80 daocloud.io/nginx:alpine

访问服务(可以多执行几次)

# 访问地址格式: swarm-manager.ip + (-p映射的端口)
curl -v 192.168.99.101:8080

然后用docker logs 查看容器中nginx的访问日志, 可以现两个容器都有访问记录

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持呐喊教程。

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