Swarm发现服务
- 用例
- 启用一个新发现后台（discovery backend）

Swarm发现服务

Docker Swarm带有多个Discovery后台

用例

使用hosted discovery服务

# create a cluster
 $ swarm create6856663cdefdec325839a4b7e1de38e8
# <- this is your unique <cluster_id>
# on each of your nodes, start the swarm agent#  <node_ip> doesn't have to be public (eg. 192.168.0.X),
#  as long as the swarm manager can access it.
$ swarm join --addr=<node_ip:2375> token://<cluster_id>
# start the manager on any machine or your laptop
$ swarm manage -H tcp://<swarm_ip:swarm_port> token://<cluster_id>
# use the regular docker cli
$ docker -H tcp://<swarm_ip:swarm_port> info
$ docker -H tcp://<swarm_ip:swarm_port> run ...
$ docker -H tcp://<swarm_ip:swarm_port> ps
$ docker -H tcp://<swarm_ip:swarm_port> logs ......
# list nodes in your cluster
$ swarm list token://<cluster_id><node_ip:2375>

使用静态文件描述服务

# for each of your nodes, add a line to a file
#  <node_ip> doesn't have to be public (eg. 192.168.0.X),
#  as long as the swarm manager can access it
$ echo <node_ip1:2375> >> /tmp/my_cluster
$ echo <node_ip2:2375> >> /tmp/my_cluster
$ echo <node_ip3:2375> >> /tmp/my_cluster# start the manager on any machine or your laptop
$ swarm manage -H tcp://<swarm_ip:swarm_port> file:///tmp/my_cluster# use the regular docker cli
$ docker -H tcp://<swarm_ip:swarm_port> info
$ docker -H tcp://<swarm_ip:swarm_port> run ...
$ docker -H tcp://<swarm_ip:swarm_port> ps
$ docker -H tcp://<swarm_ip:swarm_port> logs ......
# list nodes in your cluster
$ swarm list file:///tmp/my_cluster<node_ip1:2375><node_ip2:2375><node_ip3:2375>

使用 etcd

# on each of your nodes, start the swarm agent
#  <node_ip> doesn't have to be public (eg. 192.168.0.X),
#  as long as the swarm manager can access it.
$ swarm join --addr=<node_ip:2375> etcd://<etcd_ip>/<path>
# start the manager on any machine or your laptop
$ swarm manage -H tcp://<swarm_ip:swarm_port> etcd://<etcd_ip>/<path>
# use the regular docker cli
$ docker -H tcp://<swarm_ip:swarm_port> info
$ docker -H tcp://<swarm_ip:swarm_port> run ...
$ docker -H tcp://<swarm_ip:swarm_port> ps
$ docker -H tcp://<swarm_ip:swarm_port> logs ......
# list nodes in your cluster
$ swarm list etcd://<etcd_ip>/<path><node_ip:2375>

使用consul

# on each of your nodes, start the swarm agent
#  <node_ip> doesn't have to be public (eg. 192.168.0.X),
#  as long as the swarm manager can access it.
$ swarm join --addr=<node_ip:2375> consul://<consul_addr>/<path>
# start the manager on any machine or your laptop
$ swarm manage -H tcp://<swarm_ip:swarm_port> consul://<consul_addr>/<path>
# use the regular docker cli
$ docker -H tcp://<swarm_ip:swarm_port> info
$ docker -H tcp://<swarm_ip:swarm_port> run ...
$ docker -H tcp://<swarm_ip:swarm_port> ps
$ docker -H tcp://<swarm_ip:swarm_port> logs ......
# list nodes in your cluster
$ swarm list consul://<consul_addr>/<path><node_ip:2375>

使用zookeeper

# on each of your nodes, start the swarm agent
#  <node_ip> doesn't have to be public (eg. 192.168.0.X),
#  as long as the swarm manager can access it.
$ swarm join --addr=<node_ip:2375> zk://<zookeeper_addr1>,<zookeeper_addr2>/<path>
# start the manager on any machine or your laptop
$ swarm manage -H tcp://<swarm_ip:swarm_port> zk://<zookeeper_addr1>,<zookeeper_addr2>/<path>
# use the regular docker cli
$ docker -H tcp://<swarm_ip:swarm_port> info
$ docker -H tcp://<swarm_ip:swarm_port> run ...
$ docker -H tcp://<swarm_ip:swarm_port> ps
$ docker -H tcp://<swarm_ip:swarm_port> logs ......
# list nodes in your cluster
$ swarm list zk://<zookeeper_addr1>,<zookeeper_addr2>/<path><node_ip:2375>

　使用静态ip列表

# start the manager on any machine or your laptop
$ swarm manage -H <swarm_ip:swarm_port> nodes://<node_ip1:2375>,<node_ip2:2375>
# or
$ swarm manage -H <swarm_ip:swarm_port> <node_ip1:2375>,<node_ip2:2375>
# use the regular docker cli
$ docker -H <swarm_ip:swarm_port> info
$ docker -H <swarm_ip:swarm_port> run ...
$ docker -H <swarm_ip:swarm_port> ps
$ docker -H <swarm_ip:swarm_port> logs ......

IP地址范围匹配模式

文件和节点发现支持用范围匹配模式设定IP地址，如，10.0.0.[10:200] 为10.0.0.10 到10.0.0.200一系列节点。

例如

# file example$ echo "10.0.0.[11:100]:2375"   >> /tmp/my_cluster
$ echo "10.0.1.[15:20]:2375"    >> /tmp/my_cluster
$ echo "192.168.1.2:[2:20]375"  >> /tmp/my_cluster
# start the manager
swarm manage -H tcp://<swarm_ip:swarm_port> file:///tmp/my_cluster
# nodes example
$ swarm manage -H <swarm_ip:swarm_port> "nodes://10.0.0.[10:200]:2375,10.0.1.[2:250]:2375"

启用一个新发现后台（discovery backend）

启用新的发现后台很简单，只需实现下面的接口：

type DiscoveryService interface {
     Initialize(string, int) error
     Fetch() ([]string, error)
     Watch(WatchCallback)
     Register(string) error
}

初始化（Initialize）

这些参数是无需schema和心跳的定位。

Fetch

从discovery返回节点列表。

Watch

触发更新（Fetch）可以通过定时器（例如token）或者使用后台某些特点(如 etcd)实现。

Register

给发现服务添加新节点。