微服务之consul初体验

service discovery：consul通过DNS或者HTTP接口使服务注册和服务发现变的很容易，一些外部服务，例如saas提供的也可以一样注册。
health checking：健康检测使consul可以快速的告警在集群中的操作。和服务发现的集成，可以防止服务转发到故障的服务上面。
key/value storage：一个用来存储动态配置的系统。提供简单的HTTP接口，可以在任何地方操作。
multi-datacenter：无需复杂的配置，即可支持任意数量的区域。

Usage: consul [--version] [--help] <command> [<args>]
Available commands are:
    agent          Runs a Consul agent
    catalog        Interact with the catalog
    connect        Interact with Consul Connect
    event          Fire a new event
    exec           Executes a command on Consul nodes
    force-leave    Forces a member of the cluster to enter the "left" state
    info           Provides debugging information for operators.
    intention      Interact with Connect service intentions
    join           Tell Consul agent to join cluster
    keygen         Generates a new encryption key
    keyring        Manages gossip layer encryption keys
    kv             Interact with the key-value store
    leave          Gracefully leaves the Consul cluster and shuts down
    lock           Execute a command holding a lock
    maint          Controls node or service maintenance mode
    members        Lists the members of a Consul cluster
    monitor        Stream logs from a Consul agent
    operator       Provides cluster-level tools for Consul operators
    reload         Triggers the agent to reload configuration files
    rtt            Estimates network round trip time between nodes
    snapshot       Saves, restores and inspects snapshots of Consul server state
    validate       Validate config files/directories
    version        Prints the Consul version
    watch          Watch for changes in Consul

#consul members
Node Address Status Type Build Protocol DC Segment
cn1 192.168.1.202:8301 alive server 1.0.2 2 dc1 <all>
cn2 192.168.1.201:8301 alive server 1.0.2 2 dc1 <all>
cn3 192.168.1.200:8301 alive client 1.0.2 2 dc1 <default>

#consul  join  192.168.1.202

#consul agent  -ui  -data-dir /data/consul0 -node=cn4 -bind=192.168.1.198 -config-dir /etc/consul.d -enable-script-checks=true  -datacenter=dc1  -join 192.168.1.202

#consul agent  -ui  -data-dir /data/consul0 -node=cn4 -bind=192.168.1.198 -config-dir /etc/consul.d -enable-script-checks=true  -datacenter=dc1  -rejoin

{
    "service":{
        "name":"web",
        "tags":[
            "rails"
        ],
        "port":80,
        "check":{
            "name":"ping",
            "script":"curl -s localhost:80",
            "interval":"3s"
        }
    }
}

package main
import (
    "io"
    "log"
    "net/http"
    "strconv"
    "fmt"
)
var iCnt  int = 0;
func helloHandler(w http.ResponseWriter, r*http.request)  {
    iCnt++;
    str :="Hell eorld ! friend("+ strconv.Itoa(iCnt)+")"
    io.WriteString(w,str)
    fmt.Println(str)
}
func main(){
    ht :=http.HanderFunc(helloHandler)
    if ht != nil {
        http.Handle("/hello",ht)
    }
    err := http.ListenAndServe(":80",nil)
    if err != nil{
        log.Fatal("ListenAndserve:",err.Error())
    }
}

#go  build -o  web  web.go
#./web

# dig @127.0.0.1 -p 8600 web.service.consul SRV
;; ANSWER SECTION:
web.service.consul.  0  IN  SRV  1 1 80 cn2.node.dc1.consul.
web.service.consul.  0  IN  SRV  1 1 80 cn3.node.dc1.consul.
;; ADDITIONAL SECTION:
cn2.node.dc1.consul.  0  IN  A  192.168.1.201
cn2.node.dc1.consul.  0  IN  TXT  "consul-network-segment="
cn3.node.dc1.consul.  0  IN  A  192.168.1.200
cn3.node.dc1.consul.  0  IN  TXT  "consul-network-segment="
;; Query time: 17 msec
;; SERVER: 127.0.0.1#8600(127.0.0.1)
;; WHEN: 四 1月 04 14:39:32 CST 2018
;; MSG SIZE rcvd: 229

#!/usr/bin/env python
#encoding: utf8
#decription: registered a service to consul
from subprocess import call
import sys
hosts = {"b1":"10.10.1.01:8500","b2":"10.10.7.1:8500","b3":"10.10.8.21:8500"}
def consul_relaod():
    if (len(sys.argv) != 2) or sys.argv[1] == '-h':
        print(("Usage: {0} [option] :{1} ,if you wang update all of them,you must use 'all'").format(sys.argv[0],hosts.keys()))
        sys.exit()
    elif(sys.argv[1] == 'all'):
        for i in hosts.keys():
           call(("consul reload -http-addr {}").format(hosts[i]),shell=True)
    else:
       call(("consul reload -http-addr {}").format(hosts[sys.argv[1]]),shell=True)
if __name__ == '__main__':
    consul_relaod()

script check：
"check": {
    "args": ["/data/scripts/kubeadm-ha-0.sh",""],
    "interval": "10s"
}
http check:
{
  "check": {
       "id": "api",
       "name": "HTTP API  500",
       "http": "http://loclhost:500/health",
        "interval": "10s",
        "timeout": "1s"
}
}
tcp  check:
{
  "check": {
      "id": "ssh",
      "name": "ssh TCP 26622",
      "tcp": "localhost:26622",
      "interval": "10s",
      "timeout": "1s"
 }
}
ttl  check:
{
   "check": {
       "id": "web-app",
       "name": "Web APP status",
       "notes": "Web APP does a curl  internally every 10 seconds",
       "ttl": "30s"
}
}