Terminology

Cluster Terms

Phrase	Definition
agent	A process running in server or client mode.
client/node	A Nomad client is responsible for running tasks assigned to it. A client registers itself with servers and watches for work to be assigned. When running the agent, the client may be referred to as a node.
server	A Nomad server manages all jobs and clients, monitors tasks, and controls which tasks get placed on which nodes.
dev_agent	The development agent is an agent configuration that provides useful defaults for running a single node cluster of nomad.

Work terms

Phrase	Definition
task	The smallest unit of work in Nomad. Tasks are executed by task drivers like `docker` or `exec`, which allows Nomad to be flexible in the types of tasks it supports. Tasks specify their required task driver, configuration for the driver, constraints, and resources required.
task driver	Task drivers are used by nomad clients to execute a task and provide resource isolation.
group	A series of tasks that run on the same Nomad client.
job	The core unit of control for Nomad and defines the application and its configuration. It can contain one or many tasks
job_specification/jobspec	A job specification, also known as a jobspec defines the schema for nomad jobs. This describes the type of the job, the tasks and resources necessary for the job to run, job information like which clients it can run on, or more.
allocation	An allocation is a mapping between a task group in a job and a client node. When a job is run, Nomad will chose a client capable of running it and allocates resources on the machine for the ask(s) in the task group defined for the job.
workload artifact	The runnable blob to be scheduled on a task driver. Examples include docker images, raw binaries, java applications, and VMs using QEMU.

Typical Workflow

Running a task is generally done by:

Define a job specification for your task(s): it'll contain info like where the workload artifact is located, ports used by the service, the number of instances desired, and more.
Deploying the job: The jobspec is submitted to Nomad and it schedules an allocation for the job on one or more clients.
Updating and redploying the job.

Deployment

Installing the CLI

https://developer.hashicorp.com/nomad/tutorials/get-started/gs-install#install-the-nomad-cli

Creating a single node cluster

https://stackoverflow.com/questions/56112422/nomad-configuration-for-single-node-to-act-as-production-server-and-client

Install the nomad binary.
Create a config file with in /etc/nomad.d named config.hcl:

# https://developer.hashicorp.com/nomad/docs/configuration
# The client block configures the Nomad agent to accept jobs as assigned
# by the server.
# https://developer.hashicorp.com/nomad/docs/configuration/client
client {
  enabled = true
}
# https://developer.hashicorp.com/nomad/docs/configuration/server
server {
  enabled = true
  # The number of server nodes to wait for before bootstrapping.
  bootstrap_expect = 1
}
# The local directory where agent state is stored. 
data_dir = "/opt/nomad"
name =  "YOUR_NOMAD_NAME_HERE"

Create a Linux service nomad.service inside /etc/systemd/system:

[Unit]
Description=Nomad
Documentation=https://nomadproject.io/docs/
Wants=network-online.target
After=network-online.target

[Service]
ExecReload=/bin/kill -HUP $MAINPID
ExecStart=/usr/local/bin/nomad agent -config /etc/nomad.d
KillMode=process
KillSignal=SIGINT
LimitNOFILE=infinity
LimitNPROC=infinity
Restart=on-failure
RestartSec=2
StartLimitBurst=3
TasksMax=infinity

[Install]
WantedBy=multi-user.target

Load the service file with sudo systemctl daemon-reload, then start the service with sudo systemctl enable nomad && sudo systemctl start nomad.

6.2 KiB Raw Blame History

Terminology

Cluster Terms

Work terms

Typical Workflow

Deployment

Installing the CLI

Creating a single node cluster

Resources

6.2 KiB

Raw Blame History