Nomad

Nomad是HashiCorp推出的资源管理软体。

架构

Nomad分成Server与Client架构：

• Server负责协调与分配工作。
• Client负责实际执行工作。

正式环境下Server建议至少三台机器，Client建议至少两台机器。

安装

Nomad server与Nomad client的安装都相同（透过设定扮演不同的角色），这边是安装官方的apt repository：

curl https://apt.releases.hashicorp.com/gpg | sudo apt-key add -; sudo apt-add-repository "deb https://apt.releases.hashicorp.com $(lsb_release -cs) main"; sudo apt update && sudo apt install -y nomad

Nomad client建议再安装Docker。

设定

测试环境

单机同时跑server与client：

#
bind_addr = "0.0.0.0"
data_dir = "/opt/nomad/data"

client {
  enabled = true
  network_interface = "{{ Interfaces | limit 1 }}"
}

server {
  bootstrap_expect = 1
  enabled = true
}

正式环境

Nomad server的部份，依照官方的建议放到/etc/nomad.d/server.hcl：

datacenter = "us-east-1a"
data_dir = "/srv/nomad"
enable_syslog = true
log_level = "INFO"
region = "us-east-1"
server {
    enabled = true
    bootstrap_expect = 3
    server_join {
        retry_join = ["10.1.1.10:4648", "10.1.1.11:4648", "10.1.1.12:4648"]
    }
}

Nomad client的部份，依照官方的建议放到/etc/nomad.d/client.hcl：

datacenter = "us-east-1a"
data_dir = "/srv/nomad"
enable_syslog = true
log_level = "INFO"
region = "us-east-1"
client {
    enabled = true
    servers = ["10.1.1.10:4648", "10.1.1.11:4648", "10.1.1.12:4648"]

    chroot_env {
        "/bin" = "/bin"
        "/etc" = "/etc"
        "/lib32" = "/lib32"
        "/lib64" = "/lib64"
        "/lib" = "/lib"
        "/run/resolveconf" = "/run/resolveconf"
        "/run/systemd/resolve" = "/run/systemd/resolve"
        "/sbin" = "/sbin"
        "/usr" = "/usr"
    }
}
ports {
    http = 5656
}

设定完成后（无论是server或是client）都可以启用：

sudo service nomad restart
sudo service nomad status

档案

一份example.nomad档案：

job "example" {
  datacenters = ["us-east-1a", "us-east-1b", "us-east-1c"]
  type = "batch"
  group "example" {
    count = 10
    task "example" {
      driver = "exec"
      config {
        command = "/usr/bin/curl"
        args = ["https://wiki.gslin.org/robots.txt"]
      }
    }
  }
}

常用指令

目前测试的情况下，所有的指令都接受NOMAD_ADDR环境变数。如果没有设定环境的话，需要在命令列加上-address=http://a.b.c.d:4646参数：

export NOMAD_ADDR=http://nomad-server:4646

操作类性指令：

nomad alloc status <id>
nomad alloc logs <id>
nomad server members
nomad node status
nomad job run example.nomad
nomad job status
nomad job stop example

外部连结

• 官方网站 （英文）