2-acquiring-nodes

Acquiring nodes for use with Bolt

Difficulty: Basic

Time: Approximately 5 minutes

In this exercise you will create nodes with which you can experiment with bolt. We have provided multiple options below as examples, feel free to pick one.

• Existing nodes
• Using Vagrant
• Using Docker

Prerequisites

If you're using Vagrant or Docker you will need those installed on your local machine. For Docker we recommend Docker for Mac or Docker for Windows for people on those platforms.

Existing nodes

If you already have, or can easily launch, a few Linux or Windows nodes then you're all set. These nodes would need to be accessible via SSH or WinRM but that's it. If you can already access them via an SSH or WinRM client then bolt should be able to access them too.

Using Vagrant

Save the following as Vagrantfile, or use the file accompanying this exercise.

$nodes_count = 1

if ENV['NODES'].to_i > 0 && ENV['NODES']
  $nodes_count = ENV['NODES'].to_i
end

Vagrant.configure('2') do |config|
  config.vm.box = 'centos/7'
  config.ssh.forward_agent = true

  (1..$nodes_count).each do |i|
    config.vm.define "node#{i}" do |node|
      ip = "192.168.50.#{i+100}"
      node.vm.network "private_network", ip: ip
      ['vmware_fusion', 'vmware_workstation', 'virtualbox'].each do |provider|
        config.vm.provider provider do |_, override|
          override.ssh.host = ip
          override.ssh.port = 22
        end unless ENV['BOOT']
      end
    end
  end
end

This will by default launch one node. Run the following command. We are assuming you have some familiarity with Vagrant and have a suitable hypervisor configured.

BOOT=true vagrant up

If you would like to run more than one SSH server then you can set the NODES environment variable and run vagrant up again. With a Linux shell this is:

NODES=3 BOOT=true vagrant up

Note that the BOOT environment variable is only required when launching new nodes with vagrant up and should be left out when running other commands like vagrant ssh or vagrant ssh-config.

On Windows you can do the same thing with PowerShell:

$env:NODES = 3
vagrant up

Finally you can generate the SSH configuration so bolt knows how to authenticate with the SSH daemon. The following command will output the required details.

vagrant ssh-config

Note that if you've created more than one SSH server as above, this should be:

NODES=3 vagrant ssh-config

You can save that so it will be automatically picked up by most SSH clients, including bolt. This uses the ability to specify hosts along with there connection details in a configuration file.

mkdir ~/.ssh
NODES=3 vagrant ssh-config >> ~/.ssh/config

When passing nodes to bolt in the following exercises you will use something like --nodes node1,node2, up to the number of nodes you decided to launch. The reason you can use the node name, rather than the IP address, is the above SSH configuration file.

Using Docker

Using Docker we can quickly launch a number of ephemeral SSH servers. To make that even easier we'll use Docker Compose. Save the following as docker-compose.yml or use the file accompanying this lab.

version: '3'
services:
  ssh:
    image: rastasheep/ubuntu-sshd
    ports:
      - 22

Run the following command to launch a single SSH server in the background.

docker-compose up -d

If you'd like to launch more SSH servers then use the --scale flag like so:

docker-compose up --scale ssh=3 -d

You can see the running containers using ps:

docker-compose ps
        Name                 Command        State           Ports
-------------------------------------------------------------------------
2acquiringnodes_ssh_1   /usr/sbin/sshd -D   Up      0.0.0.0:32768->22/tcp
2acquiringnodes_ssh_2   /usr/sbin/sshd -D   Up      0.0.0.0:32769->22/tcp

Note the Ports column. We are forwarding a local port to the SSH server running in the container. So you should be able to SSH to 127.0.0.1:32768 (in the example above).

The image sets the username to root and the password to root. Test the connection out if you have a local SSH client like so, changing the port to one you get from running the docker-compose ps command above.

ssh [email protected] -p 32768

When passing nodes to bolt in the next section you will use --nodes 127.0.0.1:32768,127.0.0.1:32769, replacing the ports with those you see when you run the docker-compose ps command shown above.

Next steps

Now you have nodes with which to experiment with bolt you can move on to:

1. Running Commands