Swarm 系列 5-- 手动配置 Swarm

手动配置 swarm

• swarm 项目参考地址：https://github.com/docker/swarm
• 可以下载编译 swarm 来手动运行 swarm。swarm 是一个容器编排工具，go 编译出一个可执行文件，配合相应的配置即可运行。

1. 手动运行

• 编译后手动运行，参考：Docker Swarm discovery
• 需要自定义配置服务发现服务，代码中默认是使用 docker Hub 的开放注册服务。生产环境需要配置自己的 distributed key/value store 注册服务。
• 所以本地采用 etcd

启动etcd
james@james-CW65:/media/james/linux/yangz/software/etcd/etcd-v3.3.0-rc.1-linux-amd64 > ./etcd --config-file etcd_default.conf
2018-03-06 11:51:20.890647 I | etcdmain: Loading server configuration from "etcd_default.conf"
2018-03-06 11:51:20.893130 I | etcdmain: etcd Version: 3.3.0-rc.1
2018-03-06 11:51:20.893167 I | etcdmain: Git SHA: d3c2acf
2018-03-06 11:51:20.893185 I | etcdmain: Go Version: go1.9.2
2018-03-06 11:51:20.893202 I | etcdmain: Go OS/Arch: linux/amd64
2018-03-06 11:51:20.893219 I | etcdmain: setting maximum number of CPUs to 4, total number of available CPUs is 4
2018-03-06 11:51:20.893242 W | etcdmain: no data-dir provided, using default data-dir ./default.etcd
2018-03-06 11:51:20.893342 N | etcdmain: the server is already initialized as member before, starting as etcd member...
2018-03-06 11:51:20.893452 I | embed: listening for peers on http://172.19.128.93:2380
2018-03-06 11:51:20.893481 I | embed: pprof is enabled under /debug/pprof
2018-03-06 11:51:20.893526 I | embed: listening for client requests on 172.19.128.93:2379

加入集群，在每个机器运行swarm agent。可以看到默认每分钟，agent去注册一次。
--advertise参数是Address of the Docker Engine joining the cluster. Swarm manager(s) MUST be able to reach the Docker Engine at this address. [$SWARM_ADVERTISE]
代码中的限制是：--advertise should be of the form ip:port or hostname:port
所以使用swarm必须通过tcp方式与docker daemon通信，不能用sock文件了。
MacBook-Air:src air$ swarm join --advertise=172.19.128.148:2375 etcd://172.19.128.93:2379
INFO[0000] Initializing discovery without TLS
INFO[0000] Registering on the discovery service every 1m0s...  addr=172.19.128.148:2375 discovery=etcd://172.19.128.93:2379
INFO[0060] Registering on the discovery service every 1m0s...  addr=172.19.128.148:2375 discovery=etcd://172.19.128.93:2379
INFO[0120] Registering on the discovery service every 1m0s...  addr=172.19.128.148:2

开启swarm管理节点：
--host, -H [--host option --host option]				ip/socket to listen on [$SWARM_HOST]

MacBook-Air:ac-agent air$ swarm manage -H tcp://172.19.128.148:2377  etcd://172.19.128.93:2379
INFO[0000] Initializing discovery without TLS
INFO[0000] Listening for HTTP                            addr=172.19.128.148:2377 proto=tcp

开始使用swarm:
可以看出在该节点上使用swarm的管理节点来获取集群信息，由于swarm是安装在一个没装docker的机器上，节点也是。所以没有获取到节点的容器任何信息。
james@james-CW65:/media/james/linux/yangz/software/etcd/etcd-v3.3.0-rc.1-linux-amd64 > docker -H tcp://172.19.128.148:2377  info
Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 0
Server Version: swarm/1.2.8
Role: primary
Strategy: spread
Filters: health, port, containerslots, dependency, affinity, constraint, whitelist
Nodes: 1
 (unknown): 172.19.128.148:2375
  └ ID:
  └ Status: Pending
  └ Containers: 0
  └ Reserved CPUs: 0 / 0
  └ Reserved Memory: 0 B / 0 B
  └ Labels:
  └ Error: Cannot connect to the Docker daemon at tcp://172.19.128.148:2375. Is the docker daemon running?
  └ UpdatedAt: 2018-03-06T04:11:37Z
  └ ServerVersion:
Plugins:
 Volume:
 Network:
 Log:
Swarm:
 NodeID:
 Is Manager: false
 Node Address:
Kernel Version: 16.7.0
Operating System: darwin
Architecture: amd64
CPUs: 0
Total Memory: 0B
Name: MacBook-Air.local
Docker Root Dir:
Debug Mode (client): false
Debug Mode (server): false
Experimental: false
Live Restore Enabled: false

WARNING: No kernel memory limit support


james@james-CW65:/media/james/linux/yangz/software/etcd/etcd-v3.3.0-rc.1-linux-amd64 > ./etcdctl --endpoint http://172.19.128.93:2379 get /docker/swarm/nodes/172.19.128.148:2375
172.19.128.148:2375

• 在另一台机器上使用 swarm

加入集群，指定注册地址和服务发现服务地址：
james@james-CW65:/media/james/linux/yangz/software/docker > ./swarm_linux join --advertise=172.19.128.93:2375 etcd://172.19.128.93:2379
INFO[0000] Initializing discovery without TLS
INFO[0000] Registering on the discovery service every 1m0s...  addr=172.19.128.93:2375 discovery=etcd://172.19.128.93:2379
会显示2个节点，但是由于docker没有开放tcp连接，没办法获取docker信息
james@james-CW65:/media/james/linux/yangz/software/etcd/etcd-v3.3.0-rc.1-linux-amd64 > docker -H tcp://172.19.128.148:2377 info
Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 0
Server Version: swarm/1.2.8
Role: primary
Strategy: spread
Filters: health, port, containerslots, dependency, affinity, constraint, whitelist
Nodes: 2
 (unknown): 172.19.128.148:2375
  └ ID:
  └ Status: Pending
  └ Containers: 0
  └ Reserved CPUs: 0 / 0
  └ Reserved Memory: 0 B / 0 B
  └ Labels:
  └ Error: Cannot connect to the Docker daemon at tcp://172.19.128.148:2375. Is the docker daemon running?
  └ UpdatedAt: 2018-03-06T05:18:00Z
  └ ServerVersion:
 (unknown): 172.19.128.93:2375
  └ ID:
  └ Status: Pending
  └ Containers: 0
  └ Reserved CPUs: 0 / 0
  └ Reserved Memory: 0 B / 0 B
  └ Labels:
  └ Error: Cannot connect to the Docker daemon at tcp://172.19.128.93:2375. Is the docker daemon running?
  └ UpdatedAt: 2018-03-06T06:16:52Z
  └ ServerVersion:
Plugins:
 Volume:
 Network:
 Log:
Swarm:
 NodeID:
 Is Manager: false
 Node Address:
Kernel Version: 16.7.0
Operating System: darwin
Architecture: amd64
CPUs: 0
Total Memory: 0B
Name: MacBook-Air.local
Docker Root Dir:
Debug Mode (client): false
Debug Mode (server): false
Experimental: false
Live Restore Enabled: false

WARNING: No kernel memory limit support


MacBook-Air:src air$ swarm list  etcd://172.19.128.93:2379
INFO[0000] Initializing discovery without TLS
172.19.128.148:2375
172.19.128.93:2375
MacBook-Air:src air$

• 注意这里 swarm 仅仅提供一个集群功能。将 docker 连成了一个整体。但是在该集群上吗并不能使用新版 docker 的命令行或 API client 来操作服务，会报错 404。
• 不要混淆了独立 swarm 和 swarm mode 的区别。这里我们创建的是 swarm 集群，并不提供服务级别的功能。参考：使用 Docker Toolbox 创建 Swarm 集群的问题-概念混淆导致
• 实际运行这样也是不能创建服务的。发现只有使用 docker swarm init 来从 docker Hub 上获取的 token 才能使用 swarm mode。为什么不在 docekr swarm init 的时候提供 kv 数据存储的参数，来本地注册呢。看 swarm 源代码也可以看出再创建集群的时候，使用的是默认的 docker hub 的数据库，真不知道这个为什么不让用户用自己的。