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1：前言
在docker1.12版本之前，众所周知dokcer本身只能单机上运行，而集群则要依赖mesos、kubernetes、swarm等集群管理方案。其中swarm是docker公司自己的容器集群管理工具，在当时的热度还是低于前两者。docker1.12.0版本发布中，Docker公司出于战略眼光，将swarm集成到docker-engine中，使docker内置了集群解决方案。于是swarm这个“亲儿子”的江湖地位迅速提升，在docker集群方案中与mesos，k8s形成三足鼎立之势，在未来则大有赶超之势。
2：规划
IP 主机名 角色
10.10.32.245 swarm1 swarm manager
10.10.32.246 swarm2 worker node
10.10.32.247 swarm3 worker node
10.10.32.248 swarm4 worker node
3：集群通信原理
通过/usr/lib/system.d/system/docker.service配置开启2375管理端口
ExecStart=/usr/bin/dockerd -s overlay --insecure-registry registry.cntv.net -H tcp://0.0.0.0:2375 -H unix:///va
每个node节点上，都开启2375远程管理端口，swarm集群管理通过2375管理端口来执行
4：swarm调度原理
swarm中实现调度功能的主要是scheduler模块，其中包括Filter和strategy。
Filter：根据下发的任务的资源需求，用来过滤节点，从集群所有节点中找出满足条件的节点（比如资源足够，节点正常等等）
Strategy：用来在过滤出的节点中根据策略选择一个最优的节点（比如对找出的节点进行对比，找到资源最多的节点等等）
5：swarm集群创建
（1）初始化manager节点
$docker swarm init --advertise-addr 10.10.32.245
Swarm initialized: current node (b73yii7s7rn321ejz8n3ch7ay) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join \
--token SWMTKN-1-2z3obrzww2zcnwaiq5dzocpmvz9kty25usroy3gh3xux0l32uo-8dxurdbms8yli2crdxbmyk7y2 \
10.10.32.245:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
（2）manage查看节点swarm状态
$docker info
Swarm: active
NodeID: ax13h89zlb5dqw980ddo1ox4f
Is Manager: true
ClusterID: d5nam0mink4wdk506o1ybbs9e
Managers: 1
Nodes: 1
（3）manage查看swarm 节点
$ docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
ax13h89zlb5dqw980ddo1ox4f * swarm1 Ready Active Leader
（4）node节点加入swarm集群
- 10.10.32.246 10.10.32.247 10.10.32.248
$ docker swarm join-token manager #manage上查询加入命令及token
To add a manager to this swarm, run the following command:
docker swarm join \
--token SWMTKN-1-2z3obrzww2zcnwaiq5dzocpmvz9kty25usroy3gh3xux0l32uo-8dxurdbms8yli2crdxbmyk7y2 \
10.10.32.245:2377
$ docker swarm join \
--token SWMTKN-1-2z3obrzww2zcnwaiq5dzocpmvz9kty25usroy3gh3xux0l32uo-8dxurdbms8yli2crdxbmyk7y2 \
10.10.32.245:2377
This node joined a swarm as a worker
$ docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
03b5w49n7uz663xwjuof3dsk0 swarm4 Ready Active
0g039jomhpad819a39yvkow6y swarm2 Ready Active
4kos85v5z6jh6lahwv8yjpku8 swarm3 Ready Active
ax13h89zlb5dqw980ddo1ox4f * swarm1 Ready Active Leader
$ docker swarm leave
Node left the swarm.
6：在swarm集群上创建服务
$docker service create --network net3 --replicas 4 -p 8099:80 --name time-php registry.cntv.net/heqin/tvtime-php:v0.85dongsi
bdkwsgchcydz5ixatrbiyr1fx
$ docker service ls #查看服务
ID NAME REPLICAS IMAGE COMMAND
bdkwsgchcydz time-php 4/4 registry.cntv.net/heqin/tvtime-php:v0.85dongsi
$docker service ps time-php #查看服务的实例
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR
d15ambrdd7pyi22951vi497xa time-php.1 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm4 Running Running 5 minutes ago
3wtmmggo65cmyutg7zwikb94s time-php.2 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm3 Running Running 5 minutes ago
5ulbhndwgswpicx8g62af8k5z time-php.3 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm2 Running Running 5 minutes ago
4b9rh8aiwfi88xrdgmyss9ili time-php.4 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm2 Running Running 5 minutes ago
$docker service inspect time-php #查看服务的详细信息
[
{
"ID": "bdkwsgchcydz5ixatrbiyr1fx",
"Version": {
"Index": 3074
},
"CreatedAt": "2016-08-31T01:41:18.892483521Z",
"UpdatedAt": "2016-08-31T01:41:18.909164422Z",
"Spec": {
"Name": "time-php",
"TaskTemplate": {
"ContainerSpec": {
"Image": "registry.cntv.net/heqin/tvtime-php:v0.85dongsi"
},
"Resources": {
"Limits": {},
"Reservations": {}
},
"RestartPolicy": {
"Condition": "any",
"MaxAttempts": 0
},
"Placement": {}
},
"Mode": {
"Replicated": {
"Replicas": 4
}
},
"UpdateConfig": {
"Parallelism": 1,
"FailureAction": "pause"
},
"Networks": [
{
"Target": "d83qc9rgkkj1ws8kvmod4x759"
}
],
"EndpointSpec": {
"Mode": "vip",
"Ports": [
{
"Protocol": "tcp",
"TargetPort": 80,
"PublishedPort": 8099
}
]
}
},
"Endpoint": {
"Spec": {
"Mode": "vip",
"Ports": [
{
"Protocol": "tcp",
"TargetPort": 80,
"PublishedPort": 8099
}
]
},
"Ports": [
{
"Protocol": "tcp",
"TargetPort": 80,
"PublishedPort": 8099
}
],
"VirtualIPs": [
{
"NetworkID": "biu7m9hi8fgbbihfzg48whxqi",
"Addr": "10.255.0.19/16"
},
{
"NetworkID": "d83qc9rgkkj1ws8kvmod4x759",
"Addr": "10.88.0.2/24"
}
]
},
"UpdateStatus": {
"StartedAt": "0001-01-01T00:00:00Z",
"CompletedAt": "0001-01-01T00:00:00Z"
}
}
]
$ docker service scale time-php=10
time-php scaled to 10
$ docker service ls
ID NAME REPLICAS IMAGE
bdkwsgchcydz time-php 6/6 registry.cntv.net/heqin/tvtime-php:v0.85dongsi
$ docker service update --image registry.cntv.net/heqin/tvtime-php:v0.84xidan --log-driver=syslog time-php
time-php
$ docker service ls
ID NAME REPLICAS IMAGE
bdkwsgchcydz time-php 6/6 registry.cntv.net/heqin/tvtime-php:v0.84xidan
$docker service rm time-php
time-php
7：网络
（1）查看容器网络
$docker network ls
NETWORK ID NAME DRIVER SCOPE
a17f16650bf9 bridge bridge local #容器使用独立网络Namespace，连接docker0虚拟网卡（默认模式）
f1c102babcf8 host host local #容器与主机共享网络Namespace，拥有主机相同网卡
b6a2efce65ef none null local #容器没有任何网卡，适合不需要与外部通信的容器
asa2hv41mtci ingress overlay swarm #swarm集群的的overlay网络，容器可以跨主机网络通信
注：上面三个网络是docker安装后默认带的三个网络，第四个overlay网络是启动swarm之后默认创建的overlay网络。
（2）查看overlay网络信息
$docker network inspect ingress
[
{
"Name": "ingress",
"Id": "asa2hv41mtci2qzjkaonusnc8",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.255.0.0/16",
"Gateway": "10.255.0.1"
}
]
},
"Internal": false,
"Containers": null,
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "258"
},
"Labels": null
}
]
（3）创建自定义的overlay网络
$docker network create --driver=overlay --subnet=10.88.0.0/24 --gateway=10.88.0.1 net3
c654pb76q9jnni5bpdvd34rg4
$docker network ls
NETWORK ID NAME DRIVER SCOPE
c654pb76q9jn net3 overlay swarm
$docker network inspect net3
[
{
"Name": "net3",
"Id": "c654pb76q9jnni5bpdvd34rg4",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.88.0.0/24",
"Gateway": "10.88.0.1"
}
]
},
"Internal": false,
"Containers": null,
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "258"
},
"Labels": null
}
]
注：在manage上创建overlay网络后，各node上并没有同步创建该网络，只有当使用该overlay网络的容器在node节点上运行时，才会在node节点上自动创建,容器删除后，网络也会在node节点上删除。
（4）将容器绑定到自定义的网络中
$docker service create --network net3 --replicas 4 --name time-php registry.cntv.net/heqin/tvtime-php:v0.85dongsi
5qiv4hhv7ra5p65fpq2v6ok0x
$docker service ls
5qiv4hhv7ra5 time-php 4/4 registry.cntv.net/heqin/tvtime-php:v0.85dongsi
$docker service ps time-php
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR
529kuyazgxxl8l0eds4f740nu time-php.1 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm3 Running Running 32 seconds ago
brdelpbuwm3p9cujy6k78cpzo time-php.2 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm3 Running Running 33 seconds ago
3csp6fmrsg5cvski270732q98 time-php.3 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm2 Running Running 34 seconds ago
2ismj5zt9o3t2hfe1j1lx7dcw time-php.4 registry.cntv.net/heqin/tvtime-php:v0.85dongsi swarm4 Running Running 33 seconds ago
进入swarm3 ，可以看到net3网络下有两个容器。
$docker docker network inspect net3
[
{
"Name": "net3",
"Id": "d83qc9rgkkj1ws8kvmod4x759",
"Scope": "swarm",
"Driver": "overlay",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "10.88.0.0/24",
"Gateway": "10.88.0.1"
}
]
},
"Internal": false,
"Containers": {
"d465611683b69f20c28ec9eb276a9e4088867e35508ecf2bf28c07c5d3e1b33a": {
"Name": "time-php.1.529kuyazgxxl8l0eds4f740nu",
"EndpointID": "ca667c89550f88eabf54eeaaaa3c55c678ec8184f121fc845bbaab1cd4be20ff",
"MacAddress": "02:42:0a:58:00:05",
"IPv4Address": "10.88.0.5/24",
"IPv6Address": ""
},
"d8fa64c4f8357418304ed1f19a049e4aac196c94ef50a27a0686ebe4ee734225": {
"Name": "time-php.2.brdelpbuwm3p9cujy6k78cpzo",
"EndpointID": "ab45bcf8e73d114e9bdf97cac128750a6c7a073149783746a9962c6cd4c599a8",
"MacAddress": "02:42:0a:58:00:06",
"IPv4Address": "10.88.0.6/24",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.driver.overlay.vxlanid_list": "257"
},
"Labels": {}
}
]
用swarm3的容器去ping swarm2主机上的容器，是可以ping通的
$docker exec -it d8fa64c4f835 ping 10.88.0.3
PING 10.88.0.3 (10.88.0.3) 56(84) bytes of data.
64 bytes from 10.88.0.3: icmp_seq=1 ttl=64 time=0.611 ms
64 bytes from 10.88.0.3: icmp_seq=2 ttl=64 time=5.45 ms
64 bytes from 10.88.0.3: icmp_seq=3 ttl=64 time=0.439 ms
64 bytes from 10.88.0.3: icmp_seq=4 ttl=64 time=0.586 ms
64 bytes from 10.88.0.3: icmp_seq=5 ttl=64 time=0.603 ms
8：swarm基本命令
docker swarm Command
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
docker service Command
Commands:
create Create a new service
inspect Display detailed information on one or more services
ps List the tasks of a service
ls List services
rm Remove one or more services
scale Scale one or multiple services
update Update a service
docker service create [OPTIONS] IMAGE
Options:
--constraint value Placement constraints (default [])
--container-label value Container labels (default [])
--endpoint-mode string Endpoint mode (vip or dnsrr)
-e, --env value Set environment variables (default [])
--help Print usage
-l, --label value Service labels (default [])
--limit-cpu value Limit CPUs (default 0.000)
--limit-memory value Limit Memory (default 0 B)
--log-driver string Logging driver for service
--log-opt value Logging driver options (default [])
--mode string Service mode (replicated or global) (default "replicated")
--mount value Attach a mount to the service
--name string Service name
--network value Network attachments (default [])
-p, --publish value Publish a port as a node port (default [])
--replicas value Number of tasks (default none)
--reserve-cpu value Reserve CPUs (default 0.000)
--reserve-memory value Reserve Memory (default 0 B)
--restart-condition string Restart when condition is met (none, on-failure, or any)
--restart-delay value Delay between restart attempts (default none)
--restart-max-attempts value Maximum number of restarts before giving up (default none)
--restart-window value Window used to evaluate the restart policy (default none)
--stop-grace-period value Time to wait before force killing a container (default none)
--update-delay duration Delay between updates
--update-failure-action string Action on update failure (pause|continue) (default "pause")
--update-parallelism uint Maximum number of tasks updated simultaneously (0 to update all at once) (default 1)
-u, --user string Username or UID
9：利用2375端口远程管理
注：-H 指定远程地址和端口，即可在任意一台有docker客户端的机器远程操作swarm集群
$docker -H 10.00.32.245:2375 service ls
ID NAME REPLICAS IMAGE COMMAND
3e0ihi2lnnaa test_api 1/1 registry.cntv.net/heqin/api-web:1.1
5mdqw6r53tom test_apimem 1/1 registry.cntv.net/heqin/memcache-1.4
5ucxo9wqywo9 test_tomcatmem 1/1 registry.cntv.net/heqin/memcache-1.4
cjd1z14ug28g HQtest_tvtime 5/5 registry.cntv.net/heqin/tvtime-php:v0.85dongsi
ex4mahzt5k8u test_tomcat 1/1 registry.cntv.net/heqin/jdk7-tomcat7.0.52:201608011wq
10：swarm与mesos对比
（1）：部署配置简单，集群管理便利，但是没有web管理界面
（2）：每个节点无需手动安装agent，集群间只需要通过暴露tcp：//2375端口来保证节点间的通信。
（3）：无需bamboo来做负载均衡，swarm集群使用IPVS负载均衡
（4）：无需marathon、chrons等调度组件，swarm内置调度模块。
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