Consul Quick Start

 

What is the Consul

Consul is a service grid (TCP / IP between micro-service network calls between the responsible services, current limiting, fuse and monitoring) solution, which is a distributed, highly available system, and are developed using very simple. It provides a full-featured control plane, the main features are: service discovery, health checks, key storage, security service communication, multiple data centers.

Installation Consul

Here are two Centos: consul1, consul2
Installation:

[root@consul2 ~]# wget https://releases.hashicorp.com/consul/1.2.2/consul_1.2.2_linux_amd64.zip
[root@consul2 ~]# unzip consul_1.2.2_linux_amd64.zip 
[root@consul2 ~]# ./consul 
Usage: consul [--version] [--help] <command> [<args>]
# consul1 同上

 

Run Agent

Agent must be run after installation Consul, may choose server or client mode. Each data center has at least one server (3-5 recommendation server cluster).

For simplicity, start to develop a model of Agent:

Development model # Agent of 
[root @ consul2 ~] # ./consul Agent - dev
 ==> Starting Consul Agent ...
 ! ==> Consul Agent running 

# View cluster members 
[root @ consul2 ~] # ./ Consul Members 
the Node the Address the Status the Type the Build Protocol the DC Segment 
consul2   127.0 . 0.1 : 8301   Alive Server   1.2 . 2   2          DC1 <All> 

# using HTTP API view 
[the root @ consul2 ~] # curl localhost: 8500 / V1 / Catalog / Nodes 
[ 
    { 
        " ID " : "796b14fe-1332-4aa0-d96f-8f287a4ccc7e",
        "Node": "consul2",
        "Address": "127.0.0.1",
        "Datacenter": "dc1",
        "TaggedAddresses": {
            "lan": "127.0.0.1",
            "wan": "127.0.0.1"
        },
        "Meta " : {
             " Consul-Network-segment " : " " 
        }, 
        " the CreateIndex " : . 9 ,
         " ModifyIndex " : 10 
    } 
] 
# can also use the DNS interface query nodes (default port: 8600 ) 
[the root @ consul2 ~] # yum  install bind- utils 
[root @ consul2 ~] # @ DIG 127.0 . 0.1 -p 8600 consul2.node.consul 
... 
;; the SECTION QUESTION:  
; consul2.node.consul the IN A.
;; ANSWER the SECTION:
consul2.node.consul.    0   IN  A   127.0.0.1
...

 

Registration Service

1, the definition of a service

[root@consul2 ~]# mkdir /etc/consul.d
[root@consul2 ~]# echo '{"service": {"name": "web", "tags": ["rails"], "port": 80}}'  | sudo tee /etc/consul.d/web.json
[root@consul2 ~]# ./consul agent -dev -config-dir=/etc/consul.d

 

2, a service inquiry

# 使用 DNS API
[root@consul2 ~]# dig @127.0.0.1 -p 8600 web.service.consul
...
;; QUESTION SECTION:
;web.service.consul.        IN  A
;; ANSWER SECTION:
web.service.consul. 0   IN  A   127.0.0.1

# 使用 DNS API 查找 SRV 记录
[root@consul2 ~]# dig @127.0.0.1 -p 8600 web.service.consul SRV
...
;; QUESTION SECTION:
;web.service.consul.        IN  SRV
;; ANSWER SECTION:
web.service.consul. 0   IN  SRV 1 1 80 consul2.node.dc1.consul.
;; ADDITIONAL SECTION:
. consul2.node.dc1.consul 0   the IN A    127.0 . 0.1 
... 

# using the HTTP API query 
[root @ consul2 ~] # curl HTTP: // localhost: 8500 / v1 / Cataog / Service / Web 
# health check 
[root consul2 @ ~] # curl  ' HTTP: // localhost:? 8500 / v1 / Health / Service / Web passing '

 

Consul cluster

1, create node1, consul server

[consul1 the root @ ~] # ./consul Agent -bootstrap-Expect = -server. 1 \ 
-data-the dir = / tmp / Consul \ 
-node -bind One-Agent = = 192.168.56.112 \ 
-enable-Script-Checks = = the dir--config to true / etc / consul.d \ 
-client 0.0.0.0 - UI 
# - node: name of the node 
# - the bind: bind an address, the address used for communication between nodes, may be external network , must be accessible to the address 
# - Server: this is indicates that the node is a SERVER 
# -bootstrap- the expect: this indicates the number is expected to provide SERVER node, the number of a reach, it will be activated, then that is the LEADER 
# - DC: name specifies the data center 
# -client 0.0 . 0.0 -ui: start UI (UI in order to facilitate follow-up visit)

2, create node2, consul client

[root@consul2 ~]# ./consul agent -data-dir=/tmp/consul \
-node=agent-two   \
-bind=192.168.56.113 -enable-script-checks=true \
-config-dir=/etc/consul.d \
-ui

3, join the cluster

[root@consul2 ~]# ./consul join 192.168.56.112
Successfully joined cluster by contacting 1 nodes.
[root@consul2 ~]# ./consul members
Node       Address            Status  Type    Build  Protocol  DC   Segment
agent-one  192.168.1.13:8301  alive   server  1.2.2  2         dc1  <all>
agent-two  192.168.1.12:8301  alive   client  1.2.2  2         dc1  <default>

4, query node

[root@consul2 ~]# dig @127.0.0.1 -p 8600 agent-two.node.consul
...
;; QUESTION SECTION:
;agent-two.node.consul.     IN  A
;; ANSWER SECTION:
agent-two.node.consul.  0   IN  A   192.168.1.12

 

KV data

Similarly Redis, it is generally used for service configuration.
Learn simple command like:

consul kv put redis/config/minconns 1
consul kv put redis/config/minconns 2 # 更新
consul kv get redis/config/minconns
consul kv delete redis/config/minconns
consul kv delete -recurse redis # 批量删除

 

WEB UI

Under Access: http://192.168.56.112:8500/ui

 

Column Analysis: The above operation is something generated

1, services: placing service
2, nodes: node placed consul
3, key / value: some configuration information is placed
4, dc1: configuration data center