swarm集群：
当有多台物理机的时候，就要考虑使用集群的模式了，那么docker如何来使用集群来进行管理呢？在这里主要
使用的是docker自带的swarm mode，也就是docker集群的管理和编排。所谓的编排就是指多台集群的管理，
主机的配置，容器的调度等。
swarm mode是docker engine中自带的一种模式，很容易使用，并且无须安装其他的软件。
swarm mode的使用：
在使用swarm mode的时候，几台主机上都要先安装好docker。实验环境：
1. manager：172.25.254.84
2. server1：172.25.254.11
3. server2：172.25.254.12首先在三台机子均安装docker：
[root@foundation38 ~]# systemctl start docker
[root@foundation38 Desktop]# docker swarm init --advertise-addr 172.25.254.84
Swarm initialized: current node (epzwfk7ricu0okf97qjo1dcah) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join \
--token SWMTKN-1-2ezaq50c7h1f1u1iwrr2bagoae4n1694916z8vit4p1jcwlc2z-5usc4mbpnn6a1rkpskn0wbanc \
172.25.254.84:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
该–advertise-addr标志配置管理器节点将其地址发布为192.168.99.100。群中的其他节点必须
能够访问IP地址的管理者。
输出包括将新节点加入到群中的命令。根据–token 标志的价值，节点将作为经理或工人加入。根据
上面输出在节点上执行，token是唯一标识server1:
[root@server1 ~]# ls
docker-engine-17.03.1.ce-1.el7.centos.x86_64.rpm docker-engine-selinux-17.03.1.ce-1.el7.centos.noarch.rpm
[root@server1 ~]# vim /etc/yum.repos.d/yum.repo
[root@server1 ~]# yum repolist
Loaded plugins: product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
repo id repo name status
!rhel-source Red Hat Enterprise Linux 7Server - x86_64 - Source 4,305
repolist: 4,305
[root@server1 ~]# yum install * -y
[root@server1 ~]# systemctl start docker
[root@server1 ~]# docker swarm join --token SWMTKN-1-2ezaq50c7h1f1u1iwrr2bagoae4n1694916z8vit4p1jcwlc2z-5usc4mbpnn6a1rkpskn0wbanc 172.25.254.84:2377
This node joined a swarm as a worker.
server2：
[root@server2 ~]# ls
docker-engine-17.03.1.ce-1.el7.centos.x86_64.rpm docker-engine-selinux-17.03.1.ce-1.el7.centos.noarch.rpm
[root@server2 ~]# vim /etc/yum.repos.d/yum.repo 配置7.3yum源
[root@server2 ~]# yum repolist
Loaded plugins: product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
repo id repo name status
rhel-source Red Hat Enterprise Linux 7Server - x86_64 - Source 4,305
repolist: 4,305
[root@server2 ~]# yum install docker-engine-* -y
[root@server2 ~]# systemctl start docker
[root@server2 ~]# docker swarm join --token SWMTKN-1-2ezaq50c7h1f1u1iwrr2bagoae4n1694916z8vit4p1jcwlc2z-5usc4mbpnn6a1rkpskn0wbanc 172.25.254.84:2377
This node joined a swarm as a worker.
[root@foundation38 Desktop]# docker info 查看所有节点状态
Containers: 3
Running: 2
Paused: 0
Stopped: 1
Images: 7
Server Version: 17.03.1-ce
Storage Driver: overlay
Backing Filesystem: xfs
Supports d_type: false
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Swarm: active
NodeID: epzwfk7ricu0okf97qjo1dcah
Is Manager: true
ClusterID: qipx7hnvjusn2il88pfl87joy
Managers: 1
Nodes: 3
Orchestration:
Task History Retention Limit: 5
Raft:
Snapshot Interval: 10000
Number of Old Snapshots to Retain: 0
Heartbeat Tick: 1
Election Tick: 3
Dispatcher:
Heartbeat Period: 5 seconds
CA Configuration:
Expiry Duration: 3 months
Node Address: 172.25.254.84
Manager Addresses:
172.25.254.84:2377
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 4ab9917febca54791c5f071a9d1f404867857fcc
runc version: 54296cf40ad8143b62dbcaa1d90e520a2136ddfe
init version: 949e6fa
Security Options:
seccomp
Profile: default
Kernel Version: 3.10.0-229.el7.x86_64
Operating System: Red Hat Enterprise Linux Server 7.1 (Maipo)
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 7.388 GiB
Name: foundation38.ilt.example.com
ID: 5XOY:NMVX:KRXT:WWIQ:RE6I:DJCP:WJQD:ONMX:A7UH:LLIS:AKGH:7QES
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
WARNING: bridge-nf-call-ip6tables is disabled
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false
[root@foundation38 Desktop]# docker node ls 查看所有节点信息
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
2drpp42jfkajmalbb8424v66w server1 Ready Active
epzwfk7ricu0okf97qjo1dcah * foundation38.ilt.example.com Ready Active Leader
o5i3sivzf2zyknas7heaaczri server2 Ready Active 
部署一个服务群集：
[root@foundation38 Desktop]# docker service create --replicas 1 --name hellowalld alpine ping 172.25.254.100
v1r7925h36lyjhxza9jvj4j33
[root@foundation38 Desktop]# docker service ls
ID NAME MODE REPLICAS IMAGE
v1r7925h36ly hellowalld replicated 1/1 alpine:latest该docker service create命令创建该服务。
该–name标志命名该服务helloworld。
该–replicas标志指定了正在运行的实例的所需状态。
参数alpine ping xxx将服务定义为执行命令的Alpine Linux容器ping xxx。
运行docker service ls以查看正在运行的服务的列表：检查集群服务:
[root@foundation38 Desktop]# docker service inspect --pretty hellowalld
ID: v1r7925h36lyjhxza9jvj4j33
Name: hellowalld
Service Mode: Replicated
Replicas: 1
Placement:
UpdateConfig:
Parallelism: 1
On failure: pause
Max failure ratio: 0
ContainerSpec:
Image: alpine:latest@sha256:7043076348bf5040220df6ad703798fd8593a0918d06d3ce30c6c93be117e430
Args: ping 172.25.254.100
Resources:
Endpoint Mode: vip
[root@foundation38 Desktop]# docker service inspect hellowalld
[
{
"ID": "v1r7925h36lyjhxza9jvj4j33",
"Version": {
"Index": 21
},
"CreatedAt": "2018-08-20T13:55:54.126701518Z",
"UpdatedAt": "2018-08-20T13:55:54.126701518Z",
"Spec": {
"Name": "hellowalld",
"TaskTemplate": {
"ContainerSpec": {
"Image": "alpine:latest@sha256:7043076348bf5040220df6ad703798fd8593a0918d06d3ce30c6c93be117e430",
"Args": [
"ping",
"172.25.254.100"
],
"DNSConfig": {}
},
"Resources": {
"Limits": {},
"Reservations": {}
},
"RestartPolicy": {
"Condition": "any",
"MaxAttempts": 0
},
"Placement": {},
"ForceUpdate": 0
},
"Mode": {
"Replicated": {
"Replicas": 1
}
},
"UpdateConfig": {
"Parallelism": 1,
"FailureAction": "pause",
"MaxFailureRatio": 0
},
"EndpointSpec": {
"Mode": "vip"
}
},
"Endpoint": {
"Spec": {}
},
"UpdateStatus": {
"StartedAt": "0001-01-01T00:00:00Z",
"CompletedAt": "0001-01-01T00:00:00Z"
}
}
]
检查哪些节点在使用该服务：
[root@foundation38 Desktop]# docker service ps hellowalld
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
ifdyvv68ope8 hellowalld.1 alpine:latest foundation38.ilt.example.com Running Running 3 minutes ago
[root@foundation38 Desktop]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
61367d9e17a9 alpine@sha256:7043076348bf5040220df6ad703798fd8593a0918d06d3ce30c6c93be117e430 "ping 172.25.254.100" 21 minutes ago Up 21 minutes hellowalld.1.ifdyvv68ope8mqal9gulryqg4
90565b96c147 nginx "nginx -g 'daemon ..." About an hour ago Up About an hour 80/tcp vm2
2b8d70405744 game2048 "/bin/sh -c 'sed -..." About an hour ago Up About an hour 80/tcp, 443/tcp vm1
一旦您将服务部署到群集中，就可以使用Docker CLI来扩展服务中的容器数量。运行在服务中的容器被称为“任务”。运行以下命令以更改在群集中运行的服务的所需状态：
ocker service scale =
[root@foundation38 Desktop]# docker service scale hellowalld=5
hellowalld scaled to 5
[root@foundation38 Desktop]# docker service ps hellowalld 查看更改之后的信息
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
ifdyvv68ope8 hellowalld.1 alpine:latest foundation38.ilt.example.com Running Running 26 minutes ago
wqeu0kanb951 hellowalld.2 alpine:latest Ready Pending less than a second ago
lc6xp0er37bt \_ hellowalld.2 alpine:latest server2 Shutdown Rejected 3 seconds ago "No such image: alpine@sha256:…"
xp2b6vu3avia \_ hellowalld.2 alpine:latest server2 Shutdown Rejected 6 seconds ago "No such image: alpine@sha256:…"
sh3ohb2mqfy2 hellowalld.3 alpine:latest server2 Ready Rejected 3 seconds ago "No such image: alpine@sha256:…"
h8f6l5zz6c7u \_ hellowalld.3 alpine:latest server2 Shutdown Rejected 5 seconds ago "No such image: alpine@sha256:…"
1gm8vxv4i1l9 hellowalld.4 alpine:latest foundation38.ilt.example.com Running Running 5 seconds ago
qu5t7x9ujmad hellowalld.5 alpine:latest server2 Ready Accepted less than a second ago
c56eynow1pfe \_ hellowalld.5 alpine:latest server1 Shutdown Rejected 3 seconds ago "No such image: alpine@sha256:…"
ktmu4ulhewnj \_ hellowalld.5 alpine:latest server1 Shutdown Rejected 5 seconds ago "No such image: alpine@sha256:…" 您可以看到，swarm创建了4个新任务，可以扩展到总共5个运行的Alpine Linux实例。
任务分布在群体的三个节点之间。一个正在运行manager1。删除服务节点：
[root@foundation38 Desktop]# docker service rm hellowalld
hellowalld
[root@foundation38 Desktop]# docker service inspect helloworld
[]
Status: Error: no such service: helloworld, Code: 1
将滚动更新应用于服务：
[root@foundation38 Desktop]# docker service create --replicas 3 --name redis --update-delay 10s redis:3.0.6
55882crlxuf9d6qnr1j276dte
检查redis服务：
[root@foundation38 Desktop]# docker service inspect --pretty redis
ID: 55882crlxuf9d6qnr1j276dte
Name: redis
Service Mode: Replicated
Replicas: 3
Placement:
UpdateConfig:
Parallelism: 1
Delay: 10s
On failure: pause
Max failure ratio: 0
ContainerSpec:
Image: redis:3.0.6@sha256:6a692a76c2081888b589e26e6ec835743119fe453d67ecf03df7de5b73d69842
Resources:
Endpoint Mode: vip
更新节点版本：
[root@foundation38 Desktop]# docker service update --image redis:3.0.7 redis
redis
```
更新过程：
停止第一个任务。
为已停止的任务计划更新。
启动更新的任务的容器。
如果更新任务返回RUNNING，请等待指定的延迟时间，然后开始下一个任务。
如果在更新期间的任何时候任务返回FAILED，请暂停更新。
查看更新后的状态：变成了新的版本查看更新节点信息：
[root@foundation38 Desktop]# docker service inspect --pretty redis
ID: 55882crlxuf9d6qnr1j276dte
Name: redis
Service Mode: Replicated
Replicas: 3
UpdateStatus:
State: paused
Started: 2 minutes
Message: update paused due to failure or early termination of task zrt7rjnuy73l6vnmaau7xr5oi
Placement:
UpdateConfig:
Parallelism: 1
Delay: 10s
On failure: pause
Max failure ratio: 0
ContainerSpec:
Image: redis:3.0.7@sha256:730b765df9fe96af414da64a2b67f3a5f70b8fd13a31e5096fee4807ed802e20
Resources:
Endpoint Mode: vip
[root@foundation38 Desktop]# docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
2drpp42jfkajmalbb8424v66w server1 Ready Active
epzwfk7ricu0okf97qjo1dcah * foundation38.ilt.example.com Ready Active Leader
o5i3sivzf2zyknas7heaaczri server2 Ready Active 
将server1节点下线：
[root@foundation38 Desktop]# docker node update --availability drain server1
server1
[root@foundation38 Desktop]# docker service ps redis |grep Running
a1w7n1oh8a6v redis.1 redis:3.0.6 foundation38.ilt.example.com Running Running 35 minutes ago
46ziwdmbzczc redis.2 redis:3.0.7 foundation38.ilt.example.com Running Preparing 9 minutes ago
imgnqk20578c redis.3 redis:3.0.6 foundation38.ilt.example.com Running Running 35 minutes ago
[root@foundation38 Desktop]# docker node inspect --pretty server1
ID: 2drpp42jfkajmalbb8424v66w
Hostname: server1
Joined at: 2018-08-20 13:51:35.856400581 +0000 utc
Status:
State: Ready
Availability: Drain
Address: 172.25.254.11
Platform:
Operating System: linux
Architecture: x86_64
Resources:
CPUs: 1
Memory: 490.1 MiB
Plugins:
Network: bridge, host, macvlan, null, overlay
Volume: local
Engine Version: 17.03.1-ce
将server1节点重新上线：
将节点设置回Active可用性时，可以接收新的任务：
在服务更新期间要扩大规模
在滚动更新
当你设置另一个节点的Drain可用性
当一个任务在另一个活动节点上失败时
即后备，等下一个滚动更新，加入集群或者替代死的[root@foundation38 Desktop]# docker node update --availability active server1
server1
[root@foundation38 Desktop]# docker node inspect --pretty server1
ID: 2drpp42jfkajmalbb8424v66w
Hostname: server1
Joined at: 2018-08-20 13:51:35.856400581 +0000 utc
Status:
State: Ready
Availability: Active
Address: 172.25.254.11
Platform:
Operating System: linux
Architecture: x86_64
Resources:
CPUs: 1
Memory: 490.1 MiB
Plugins:
Network: bridge, host, macvlan, null, overlay
Volume: local
Engine Version: 17.03.1-ce