当你没有使用swarm时候，使用是docker的命令，如果使用swarm这使用的是swarm提供的一些命令服务编排进行操作，可以但节点使用或者集群服务。尽管这些服务大多数是无状态的，但是，我们应该明白，一旦使用集群那么很多东西都需要进行考虑，比如存储方案，使用本地存储还是跨主机存储，如何进行选型等，镜像参考，编排工具等。总而言之，swarm也是很好的选择，我们可以进行简单安装和配置。
Swarm守护进程是使用Go编写，发展的速度非常快，在使用中但swarm Leader(Manager)节点创建后，其他工作节点加入后，集中管理在Leader节点，工作节点接收并执行从管理器节点分派的任务。默认情况下，管理器节点也会以服务器节点运行服务，它可能是这样的：
了解searm：https://docs.docker.com/engine/swarm/key-concepts/#what-is-a-node
https://docs.docker.com/engine/swarm/#feature-highlights
在开始之前，参与的机器需要能够互通，并且安装docker
swarm节点
[root@DS-VM-Node117-LinuxEA ~]# docker swarm init --advertise-addr 10.10.240.117 --listen-addr 0.0.0.0
Swarm initialized: current node (as4u4yh1h5h84y06h2etad4yb) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join
--token SWMTKN-1-4s87dp8n3mlraw9vd1amq6b2x3007it5n609t6ls82n3lj0mm8-agkh99gkc1ezyk8jnlev0kckz
10.10.240.117:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
[root@DS-VM-Node117-LinuxEA ~]# 添加防火墙规则：iptables -I INPUT 4 -p tcp --dport 2377 -j ACCEPT
worker节点：
[root@DS-VM-Nod114-LinuxEA ~]# docker swarm join --token SWMTKN-1-4s87dp8n3mlraw9vd1amq6b2x3007it5n609t6ls82n3lj0mm8-agkh99gkc1ezyk8jnlev0kckz 10.10.240.117:2377
This node joined a swarm as a worker.
[root@DS-VM-Nod114-LinuxEA ~]# swarm查看
[root@DS-VM-Node117-LinuxEA ~]# docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
34lehmydkl4sji5o799y813nr DS-VM-Nod114-LinuxEA.cluster.com Ready Active
as4u4yh1h5h84y06h2etad4yb * DS-VM-NodeLinuxEA.cluster.com Ready Active Leader
[root@DS-VM-Node117-LinuxEA ~]# 在加一台
[root@DS-VM-Node98-LinuxEA ~]# docker swarm join --token SWMTKN-1-4s87dp8n3mlraw9vd1amq6b2x3007it5n609t6ls82n3lj0mm8-agkh99gkc1ezyk8jnlev0kckz 10.10.240.117:2377
This node joined a swarm as a worker.
[root@DS-VM-Node98-LinuxEA ~]#此时有两台workd加入到集群中
[root@DS-VM-Node117-LinuxEA ~]# docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
34lehmydkl4sji5o799y813nr DS-VM-Nod114-LinuxEA.cluster.com Ready Active
as4u4yh1h5h84y06h2etad4yb * DS-VM-Node117-LinuxEA.cluster.com Ready Active Leader
d464utrj8hgseauht11zddy2i DS-VM-Node98-LinuxEA.cluster.com Ready Active 我们运行一个服务来大致了解下简单的使用方法：
创建一个服务
[root@DS-VM-Node117-LinuxEA ~]# docker service create --replicas 1 --name helloworld alpine ping docker.com
82q0h1jwpudm91g4fkgr0l3v4
查看
[root@DS-VM-Node117-LinuxEA ~]# docker service ls
ID NAME REPLICAS IMAGE COMMAND
82q0h1jwpudm helloworld 0/1 alpine ping docker.com查看状态
[root@DS-VM-Node117-LinuxEA ~]# docker service inspect --pretty helloworld
ID: 82q0h1jwpudm91g4fkgr0l3v4
Name: helloworld
Mode: Replicated
Replicas: 1
Placement:
UpdateConfig:
Parallelism: 1
On failure: pause
ContainerSpec:
Image: alpine
Args: ping docker.com
Resources:
[root@DS-VM-NodeLinuxEA ~]#此时服务运行在集群的这台机器，我们扩展下，使他运行到work两台上
[root@DS-VM-Node117-LinuxEA ~]# docker service scale helloworld=5
helloworld scaled to 5查看，有的在启动的状态
[root@DS-VM-Node117-LinuxEA ~]# docker service ps helloworld
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR
8odhtpxb0fe4sqaq2t82jbzmg helloworld.1 alpine DS-VM-Node117-LinuxEA.cluster.com Running Running 7 minutes ago
aphzf56gddnmznq0scgiec6js helloworld.2 alpine DS-VM-Nod114-LinuxEA.cluster.com Running Starting less than a second ago
4hg4qhg9v40w0hc6yyt8oaqmz helloworld.3 alpine DS-VM-Nod114-LinuxEA.cluster.com Running Starting less than a second ago
5s62m16vlvsvnu4zqdj6ffen9 helloworld.4 alpine DS-VM-Node98-LinuxEA.cluster.com Running Running less than a second ago
bgbjw088bb2meqbman2ubz54t helloworld.5 alpine DS-VM-Node98-LinuxEA.cluster.com Running Running less than a second ago在查看都启动完成
[root@DS-VM-Node117-LinuxEA ~]# docker service ps helloworld
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR
8odhtpxb0fe4sqaq2t82jbzmg helloworld.1 alpine DS-VM-Node117-LinuxEA.cluster.com Running Running 10 minutes ago
aphzf56gddnmznq0scgiec6js helloworld.2 alpine DS-VM-Nod114-LinuxEA.cluster.com Running Running less than a second ago
4hg4qhg9v40w0hc6yyt8oaqmz helloworld.3 alpine DS-VM-Nod114-LinuxEA.cluster.com Running Running less than a second ago
5s62m16vlvsvnu4zqdj6ffen9 helloworld.4 alpine DS-VM-Node98-LinuxEA.cluster.com Running Running less than a second ago
bgbjw088bb2meqbman2ubz54t helloworld.5 alpine DS-VM-Node98-LinuxEA.cluster.com Running Running less than a second ago
[root@DS-VM-Node117-LinuxEA ~]# 到work机器查看：
[root@DS-VM-Nod114-LinuxEA ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4266875173af alpine:latest "ping docker.com" 40 seconds ago Up Less than a second helloworld.3.4hg4qhg9v40w0hc6yyt8oaqmz
2fa0d6351756 alpine:latest "ping docker.com" 40 seconds ago Up 3 seconds helloworld.2.aphzf56gddnmznq0scgiec6js
[root@DS-VM-Nod114-LinuxEA ~]#
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d0690fd20f3d alpine:latest "ping docker.com" 4 minutes ago Up 4 minutes helloworld.4.5s62m16vlvsvnu4zqdj6ffen9
f5e90f235064 alpine:latest "ping docker.com" 4 minutes ago Up 4 minutes helloworld.5.bgbjw088bb2meqbman2ubz54t
[root@DS-VM-Nod114-LinuxEA ~]# 删除服务
[root@DS-VM-Node117-LinuxEA ~]# docker service rm helloworld
helloworld
[root@DS-VM-Node117-LinuxEA ~]# docker service inspect helloworld
[]
Error: no such service: helloworld即使服务不再存在，任务容器需要几秒钟的时间来清理。您可以使用docker ps节点来验证任务何时被删除。
