gistfile1.txt

# Simple manifest
# by vkhomenko
#
# We want to create VM, and run bash command on it.
# We need 2 steps: provision (ask amazon to launch instance) and run-command.
# To define order for our steps, we use "phase - precedingPhases". precedingPhases means we shall wait until phases listed there finished.
# Also, after starting node, we need a way to access it. Adding roleName, we adds our node to pool, named "computes-pool".
# Parameter "roles", passed to execrun, tells where to execute command. Right now it's just one node.

launch:
  parameters:
      - ip:
          description: IP
          default: 54.211.39.45
  steps:
    - provision-vm:                          # Name of step
        action: compute.grow                 # Predefined action that adds compute node
        parameters:
          ip: "{$.ip}"
          roleName: computes-pool            # Name of pool we create.
          phase: init                        # Phase name, for ordering.
        output:                              # After running, action "compute.grow" will return some variables, "ips" is one of them.
          vm-ips: ips                        # We declare that our step should return it to step caller, so it can be accessible for other steps.

    - run-command:                           # Name of step
        action: execrun                      # Predefined action that executes shell command
        parameters:
          roles: [computes-pool]             # Where to run command. We've created one vm on privious step. What square braces means???
          precedingPhases: [init]            # We declare that step must be executed after "init" phase finished.
          command:                           # Parameter for execrun, passes command to execute
            - 'echo "Hello from execrun!"'
        output:                              # What this step should return
          cmd-out: stdout                    # Action "execrun" returns console output in "stdout" variable, we name it cmd-out, to use later
  return:                                    # Here we declare what our application should return
    vm-host:                                 # Name of variable
      value: '{$.vm-ips}'                    #? Value we can from local variables of manifest ???
      description: Newly created VM address  # Just description, to be shown in UI instead of "vm-host"
    console-output:
      value: '{$.cmd-out}'

destroy:                                     # Mandatory paramenter
  steps:
    - destroy-vm:
        action: compute.shrink-all           # Predefined action, destroys all created VM's

# Running this manifest will result in:
#
# console-output {174.129.222.333 : Hello from execrun!}
# Newly created VM address 174.129.222.33
# That means we created virtual machine and executed echo there