Getting Started with Nomad

about Nomad

Nomad is a tool that manages the machine cluster and runs the application on the cluster.

Nomad Features: Jobs that support Docker,nomad can deploy applications to the cluster using Docker drivers. Nomad installs only a single binary in Linux and does not require additional service coordination, and Nomad integrates the capabilities of the Resource manager and scheduler into one system. Multiple data centers that can be dispatched across data centers. Distributed high availability, support for multiple drivers (Docker, VMS, Java) run job, support for multiple systems (Linux, Windows, BSD, OSX). Nomad Installation

In general, install Vagrant First, and use vagrant to connect to local VirtualBox to create a local test environment. However, due to the lack of components in the local Win7 environment during the learning process, the vagrant cannot be installed and used.
So use a Linux virtual machine directly to learn. This environment uses Ubuntu16.04,docker version 17.09.0-ce.

Download the Nomad binaries and select the appropriate installation package for your system.

# wget Https://releases.hashicorp.com/nomad/0.7.0/nomad_0.7.0_linux_amd64.zip?_ga= 2.169483045.503594617.1512349197-1498904827.1511322624

Unzip the installation package and place the Nomad file under/usr/local/bin.

# unzip-o nomad_0.7.0_linux_amd64.zip-d/usr/local/bin/
# cd/usr/local/bin
# chmod +x Nomad

Terminal Input Nomad, you can see the NOMAD hint that the installation was successful.
Start Nomad

To run in a simple way, we run the Nomad agent in development mode. The development model can quickly launch server-side and client-side, test-learning nomad.

# Nomad Agent-dev ==> starting Nomad agent ... ==> nomad agent Configuration:Client:true Log level:debug Region:global (DC:DC1) server:true ==> Nomad Agent started! Log data would stream in below: [INFO] serf:EventMemberJoin:nomad.global 127.0.0.1 [INFO] nomad:starting 4 sche Duling worker (s) for [service batch _core] [info] client:using alloc directory/tmp/nomadclient599911093 [INFO] R Aft:node at 127.0.0.1:4647 [Follower] Entering Follower State [INFO] nomad:adding server Nomad.global (addr:127.0.0 .1:4647) (DC:DC1) [WARN] Fingerprint.network:Ethtool not found, checking/sys/net speed file [WARN] Raft:heartb Eat timeout reached, starting election [INFO] Raft:node at 127.0.0.1:4647 [candidate] entering candidate state [D Ebug] Raft:votes needed:1 [DEBUG] raft:vote granted. tally:1 [INFO] Raft:election won. tally:1 [INFO] Raft:node at 127.0.0.1:46[Leader] Entering Leader State [INFO] raft:disabling Enablesinglenode (bootstrap) [DEBUG] Raft:node 127.0.0.1 : 4647 updated Peer set (2): [127.0.0.1:4647] [INFO] nomad:cluster leadership acquired [DEBUG] client:applied fin Gerprints [Arch CPU host Memory storage network] [debug] client:available drivers [docker exec Java] [debug] Clie Nt:node registration Complete [DEBUG] client:updated allocations at index 1 (0 allocs) [Debug] Client:allocs: ( Added 0) (removed 0) (updated 0) (ignore 0) [DEBUG] client:state updated to Ready

As seen in the terminal output, both server and client are true, indicating that both server and client are turned on. Nomad cluster Nodes

# Nomad Node-status

ID             DC   Name           Class   Drain  status
fb533fd8  DC1  yc-jumpbox  <none>  false  ready

The output shows our node ID, which is a randomly generated UUID, its data center, node name, node category, funnel mode, and current state. We can see that our node is in the ready state.

# Nomad Server-members

Name                      Address     Port  Status  Leader  Protocol  Build  Datacenter  Region
yc-jumpbox.global  10.30.0.52  4648  Alive   true            2         0.7.0  DC1             Global

The output shows our own server, the running address, the health, some version information, and the data center and region. Stop Nomad Agent

You can use Ctrl-c to interrupt the agent. By default, all signals cause the agent to be forced to shut down. Nomad Job

Job is our main interactive content with Nomad. Sample Job

Enter your working directory using the NOMAD init command. It generates a Example.nomad in the current directory, which is an example of the Nomad job configuration file.
# cd/tmp
# Nomad init
Example job file written to Example.nomad

To run this job, we use the Nomad Run command.

# Nomad Run Example.nomad   
==> monitoring Evaluation "13EBB66D"
    evaluation triggered by job "example"
    Allocation "883269BF" Created:node "e42d6f19", Group "cache"
    Evaluation within Deployment: "B0a84e74"
    Evaluation status changed: ' Pending ', ' complete '
==> Evaluation ' 13ebb66d ' finished with status ' complete '

To view the job status, we use the Nomad status command

# Nomad Status Example
ID            = Example
Name          = Example
Submit Date   = 12/05/17 10:58:40 UTC
Type          = Service
Priority      =
datacenters   = DC1
Status        = running
periodic      = False
parameterized = False

Summary
Task Group  Queued  starting  Running  Failed  Complete  Lost
cache       0       0         1        0       0         0

Latest Deployment
ID          = B0a84e74
Status      = successful
Description = Deployment completed successfully

Deployed
Task Group  desired  Placed  Healthy  unhealthy
cache       1        1       1        0

Allocations
ID        Node ID   Task Group  Version  desired  Status   Created
at 883269BF  e42d6f19  cache       0        run      running  12/05/17 10:58:40 UTC

To check the job assignment, we use the Nomad alloc-status command.

# Nomad alloc-status 83269BF id = 83269bf Eval id = 3ebb66d Name = EXAMPLE.CAC HE[0] Node id = e42d6f19 Job id = Example Job Version = 0 Client Status = running C Lient Description = <none> desired Status = run desired Description = <none> Created at = 12/05 /17 10:58:49 UTC Deployment ID = b0a84e74 Deployment health = Healthy Task "Redis" is "Running" task Resources CP U Memory Disk IOPS Addresses 8/500 MHz 6.3 mib/256 MiB 0 db:127.0.0.1:22672 Task Ev
ents:started at = 12/05/17 10:58:49 UTC finished at = n/A total restarts = 0 Last Restart = N/A recent Events:  Time Type Description 10/31/17 22:58:49 UTC Started Task Started by client 10/31/17 22:58:40  UTC Driver downloading image redis:3.2 10/31/17 22:58:40 UTC task Setup Building task Directory 10/31/17 22:58:40 UTC Received Task REceived by client 

To view the job log, we use the Nomad Logs command. Note the parameters that follow the logs are UUID and task names. The UUID can be obtained through the Nomad status Example command, and the task name is defined in the Example.nomad configuration file.

# Nomad Logs 883269bf Redis
                 _._
            _.-' __ '-._
       _.-'    .  `_.  '' -._