Consul cluster deployment

Consul brief introduction

Consul yes HashiCorp Open source software launched by the company , be based on GO Language writing , Provide service registration and discovery 、 To configure 、 High availability solutions and other capabilities of multiple data centers , The distributed consistency aspect adopts raft Algorithm implementation , And it's easy to Spring Cloud Isomicroservice framework integration , It's very simple to use , Simple 、 Easy to use 、 Pluggable and other features .

In short ,Consul It is the control plane of the service grid ,Consul Provides a complete service grid solution .

Consul The running nodes are connected , It's called the data center , A data center will have 3 To 5 Servers and many clients .Consul The cluster architecture is as follows ：

Consul Cluster deployment

Here we use 3Server + 1Client Cluster architecture of ,3 platform Server On a separate virtual machine ,1 platform Client Then run directly on the host of the deployment service .

The name of the node	node IP	Agent type	OS edition
consul-01	192.168.94.10	server	Ubuntu 22.04 LTS
consul-02	192.168.94.11	server	Ubuntu 22.04 LTS
consul-03	192.168.94.12	server	Ubuntu 22.04 LTS
consul-client	192.168.94.13	client	Ubuntu 22.04 LTS

1、 install Consul

Configure host name , Order sample ：（ The following operations are configured on all nodes ）

 hostnamectl set-hostname consul-01
 hostnamectl set-hostname consul-02
 hostnamectl set-hostname consul-03
 hostnamectl set-hostname consul-client

download consul Binary

export VER="1.12.3"
wget https://releases.hashicorp.com/consul/${VER}/consul_${VER}_linux_amd64.zip

Unpack the installation

apt install -y unzip
unzip consul_${VER}_linux_amd64.zip -d /usr/local/bin/

View version

 consul version

establish consul Users and groups

sudo groupadd --system consul
sudo useradd -s /sbin/nologin --system -g consul consul

establish consul The installation directory

mkdir -p /data/consul/{
    config,data,logs}
chown -R consul:consul /data/consul
chmod -R 775 /data/consul

Set up DNS Or edit /etc/hosts File to configure the hostname of all servers , Replace example.com For your actual domain name .

cat >/etc/hosts<<EOF 192.168.94.10 consul-01.example.com consul-01 192.168.94.11 consul-02.example.com consul-02 192.168.94.12 consul-03.example.com consul-03 192.168.94.13 consul-client.example.com consul-client EOF

2、Server Node configuration

Generate Consul secret

consul keygen

by server Node creation json The configuration file , Other node configurations are modified IP Address and node name

consul-01 node

cat >/data/consul/config/consul.json<<EOF
{
    
    "advertise_addr": "192.168.94.10",
    "bind_addr": "192.168.94.10",
    "bootstrap_expect": 3,
    "client_addr": "0.0.0.0",
    "datacenter": "DC1",
    "node_name": "consul-01", 
    "data_dir": "/data/consul/data",
    "domain": "consul",
    "enable_script_checks": true,
    "dns_config": {
    
        "enable_truncate": true,
        "only_passing": true
    },
    "enable_syslog": true,
    "encrypt": "F0VSq05Die32sMUimbZ2LAzUIc5Ry4jCL2ouwz/Gu8Q=",
    "leave_on_terminate": true,
    "log_level": "INFO",
    "rejoin_after_leave": true,
    "retry_join": [
     "consul-01",
     "consul-02",
     "consul-03"
    ],
    "server": true,
    "start_join": [
        "consul-01",
        "consul-02",
        "consul-03"
    ],
    "ui": true
}
EOF

Configuration parameter description ：

• datacenter： This flag controls the data center where the agent runs . If not provided , The default is dc1.Consul First class support for multiple data centers , But it depends on the correct configuration . Nodes in the same data center should be located in a single location LAN On .

• data_dir： This flag provides a data directory for the agent to store state .

• node_name： Node name , Usually the host name .

• server： Specify whether to be server node .

• bootstrap_expect： In a datacenter We hope to provide server Number of nodes , When this value is provided ,consul Wait until the designated sever The number will guide the whole cluster , The mark cannot be used with bootstrap public .

• bind_addr： This address is used for communication within the cluster , All nodes in the cluster must be reachable , The default is 0.0.0.0.

• client_addr：Consul Will bind the address of the client interface , Include HTTP and DNS The server . By default , This is a 127.0.0.1, Only loopback connections are allowed . stay Consul 1.0 And later , This can be set to a space delimited address list to bind to .

• log_json： This flag enables the agent to JSON Format output log . The default is false.

• log_level: stay Consul The log level displayed after the agent starts . The default is info . The available log levels are trace、debug、info、warn and err.

• retry_join： Specify the IP list , If you fail , Will automatically retry , Know until you successfully join .

• start_join： The address to join the cluster at startup

• ui_config： This object allows you to set multiple subkeys , Used to control the UI Displays or functions available in .

• rejoin_after_leave ： Allow rejoining the cluster

consul-02 node

cat >/data/consul/config/consul.json<<EOF
{
    
    "advertise_addr": "192.168.94.11",
    "bind_addr": "192.168.94.11",
    "bootstrap_expect": 3,
    "client_addr": "0.0.0.0",
    "datacenter": "DC1",
    "node_name": "consul-02", 
    "data_dir": "/data/consul/data",
    "domain": "consul",
    "enable_script_checks": true,
    "dns_config": {
    
        "enable_truncate": true,
        "only_passing": true
    },
    "enable_syslog": true,
    "encrypt": "F0VSq05Die32sMUimbZ2LAzUIc5Ry4jCL2ouwz/Gu8Q=",
    "leave_on_terminate": true,
    "log_level": "INFO",
    "rejoin_after_leave": true,
    "retry_join": [
     "consul-01",
     "consul-02",
     "consul-03"
    ],
    "server": true,
    "start_join": [
        "consul-01",
        "consul-02",
        "consul-03"
    ],
    "ui": true
}
EOF

consul-03 node

cat >/data/consul/config/consul.json<<EOF
{
    
    "advertise_addr": "192.168.94.12",
    "bind_addr": "192.168.94.12",
    "bootstrap_expect": 3,
    "client_addr": "0.0.0.0",
    "datacenter": "DC1",
    "node_name": "consul-03", 
    "data_dir": "/data/consul/data",
    "domain": "consul",
    "enable_script_checks": true,
    "dns_config": {
    
        "enable_truncate": true,
        "only_passing": true
    },
    "enable_syslog": true,
    "encrypt": "F0VSq05Die32sMUimbZ2LAzUIc5Ry4jCL2ouwz/Gu8Q=",
    "leave_on_terminate": true,
    "log_level": "INFO",
    "rejoin_after_leave": true,
    "retry_join": [
     "consul-01",
     "consul-02",
     "consul-03"
    ],
    "server": true,
    "start_join": [
        "consul-01",
        "consul-02",
        "consul-03"
    ],
    "ui": true
}
EOF

3、Client Node configuration

client yes consul client , The client does not save data , The client forwards the received request to Server End .Server Data consistency is achieved through LAN or WAN communication between . Every Server or Client It's all one consul agent.

establish consul-client Node profile

cat >/data/consul/config/consul.json<<EOF
{
    
    "advertise_addr": "192.168.94.13",
    "bind_addr": "192.168.94.13",
    "client_addr": "0.0.0.0",
    "datacenter": "DC1",
    "node_name": "consul-client", 
    "data_dir": "/data/consul/data",
    "domain": "consul",
    "enable_script_checks": true,
    "dns_config": {
    
        "enable_truncate": true,
        "only_passing": true
    },
    "enable_syslog": true,
    "encrypt": "F0VSq05Die32sMUimbZ2LAzUIc5Ry4jCL2ouwz/Gu8Q=",
    "leave_on_terminate": true,
    "log_level": "INFO",
    "rejoin_after_leave": true,
    "retry_join": [
     "consul-01",
     "consul-02",
     "consul-03"
    ],
    "server": false,
    "start_join": [
        "consul-01",
        "consul-02",
        "consul-03"
    ],
    "ui": true
}
EOF

4、systemd Startup file

All nodes created systemd Service document /etc/systemd/system/consul.service, All nodes have the same content , The configuration is as follows ：

cat >/etc/systemd/system/consul.service<<EOF [Unit] Description=Consul Service Discovery Agent Documentation=https://www.consul.io/ After=network-online.target Wants=network-online.target [Service] Type=simple User=consul Group=consul ExecStart=/usr/local/bin/consul agent -config-dir=/data/consul/config/consul.json ExecReload=/bin/kill -HUP $MAINPID KillSignal=SIGINT TimeoutStopSec=5 Restart=on-failure SyslogIdentifier=consul [Install] WantedBy=multi-user.target EOF

All nodes start consul service

systemctl enable --now consul.service

see consul Service running status

[email protected]:~# systemctl status consul
● consul.service - Consul Service Discovery Agent
     Loaded: loaded (/etc/systemd/system/consul.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2022-07-19 11:17:02 CST; 3s ago
       Docs: https://www.consul.io/
   Main PID: 46248 (consul)
      Tasks: 8 (limit: 4537)
     Memory: 23.3M
        CPU: 249ms
     CGroup: /system.slice/consul.service
             └─46248 /usr/local/bin/consul agent -config-dir=/data/consul/config/consul.json

Jul 19 11:17:03 consul-01 consul[46248]: agent: Joining cluster
Jul 19 11:17:03 consul-01 consul[46248]: agent: (LAN) joining: lan_addresses=[consul-01, consul-02, consul-03]
Jul 19 11:17:03 consul-01 consul[46248]: agent: (LAN) joined: number_of_nodes=3
Jul 19 11:17:03 consul-01 consul[46248]: agent: Join cluster completed. Synced with initial agents: cluster=LAN num_agents=3
Jul 19 11:17:03 consul-01 consul[46248]: agent: (LAN) joined: number_of_nodes=3
Jul 19 11:17:03 consul-01 consul[46248]: agent: Join completed. Initial agents synced with: agent_count=3
Jul 19 11:17:03 consul-01 consul[46248]: agent: started state syncer
Jul 19 11:17:03 consul-01 consul[46248]: agent: Consul agent running!
Jul 19 11:17:03 consul-01 consul[46248]: 2022-07-19T11:17:03.431+0800 [INFO]  agent: Synced node info
Jul 19 11:17:03 consul-01 consul[46248]: agent: Synced node info

5、 see Consul State of the cluster

3 platform Server and 1 platform Client Upper Consul After the services are started, they will be based on consul.json The configuration in automatically forms a cluster , also Server Will pass Raft The agreement Server Choose... From the nodes leader node .

You can use the following command to view the status of cluster nodes on any machine ：

[email protected]:~# consul members
Node           Address             Status  Type    Build   Protocol  DC   Partition  Segment
consul-01      192.168.94.10:8301  alive   server  1.12.3  2         dc1  default    <all>
consul-02      192.168.94.11:8301  alive   server  1.12.3  2         dc1  default    <all>
consul-03      192.168.94.12:8301  alive   server  1.12.3  2         dc1  default    <all>
consul-client  192.168.94.13:8301  alive   client  1.12.3  2         dc1  default    <default>

see server Node member status information ：

[email protected]:~# consul operator raft list-peers
Node       ID                                    Address             State     Voter  RaftProtocol
consul-02  edefb129-e0fd-804d-bbfb-76e259077d03  192.168.94.11:8300  leader    true   3
consul-01  50f9830f-45cd-683c-2382-77e1cf6d6e48  192.168.94.10:8300  follower  true   3
consul-03  5dae09d2-7079-4611-1ab5-7728d0966cbe  192.168.94.12:8300  follower  true   3

visit Consul UI：http://192.168.94.10:8500/ui

Reference resources ：

• https://www.cnblogs.com/wangguishe/p/15599233.html
• https://computingforgeeks.com/how-to-install-consul-cluster-18-04-lts/