Design Summit - Intro to State Machines - John Hardy

State Machines

A big look at them from all angles!

John HardyProduct Manager

Fall 2014

Agenda

• What is a state machine?

• Real Life State Machines

• What is the difference between a State Machine and WorkFlow?

• Cyclic Graphs

• Acyclic Graphs

• The StateMachine

• Our StateMachine

• Fisher Price My First StateMachine

• Review : Why Are we talking statemachines?

• Wanna play? How to invoke statemachines.

• Q&A

What is a State Machine?

1. A state machine is simply a number of states.

2. A state is a process, something happening.

3. Only one state can be current at any one time.

4. The state of a state can be changed.

5. The initial entrance is event triggered, could be conditionally based.

6. Every change to a state is a transition.

Real Life State Machines

Traffic Lights – That change their sequence based on the cars waiting.

Turn Stile

Current

StateInput Next State Output

Lockedcoin Unlocked Release turnstile so customer can push through

push Locked None

Unlocked

coin Unlocked None

push LockedWhen customer has pushed through lock

turnstile.

What is the difference?

The shortest answer is that StateMachines are Cyclic and Workflows are Acyclic.

Workflows tend to be human representations to how a job is done, therefore ends, directive and event driven are

common place.

StateMachines are a map of states with transitions between them, sometimes allowing for loops.

Between a StateMachine and a WorkFlow

Cyclic Graphs

BA C

ED F

Cyclic graphs have CYCLES, as you can see here B,C,E,D.

At point E the graph decides to go F or to D and into a cycle.

Acyclic Graphs

BA

C E

D

F

aCyclic graphs are directive, shown here no point starts a cycle, only

completion to end.

Action

System/request

familycarClick Button

Instance

cfnow/fisherprice/myfir

ststatemachine

familycar

Attribute

number of

doors = 4

Value

cfnow/fisherprice/met

hods

Validate_car

On Entry Exit States


hods

Validate_error


hods

Build_car


hods

build_error


hods

Test_car


hods

Test_error


hods

Test_Complet

ed

$evm.root['ae_result'] = 'retry'


$evm.root['ae_retry_interval'] =

'10.seconds'


'10.seconds'

The State Machine

Action

System/request

familycarClick Button

Instance

cfnow/fisherprice/myfir

ststatemachine

familycar

Attribute

number of

doors = 4

Value


hods

Validate_car

On Entry Exit States


hods

Validate_error


hods

Build_car


hods

build_error


hods

Test_car


hods

Test_error


hods

Test_Complet

ed




'10.seconds'


'10.seconds'

The State Machine

State Machine

ae_result

• retry

• ok

• error

Our State Machines

Many state machines exist already in ManageIQ/CF

• Provisioning Hosts

• Provisioning Virtual Machines

• Provisioning Instances

• Retirement Hosts

• Retirement Virtual Machines

• Retirement Instances

• Provisioning Services

• Retirement Services

• Migration Virtual Machines

These can be copied and amended as you see fit.

So its not about creating state machine from new all the time.

Our State Machines – Provisioning VM

Starting with the basics

My First State Machine

My First State Machine

StateMachine

Goal – To teach the concepts of state machine

Give you some best practices, why?

Good State-Machines = Re-usable and Portable

Not to mention easier to debug too!

– My First StateMachine!

Skipping HelloWorld – That was My First Method!

Car Example – We are going to build a car, that during manufacturing we shall

up date the manufacturing cycle too. First steps will be;

1. Specify how many doors our car should have.

2. Validate the number of doors defined.

3. Error out if the doors are too many.

4. Build the car.

• The doors will be set on the StateMachine itself, and pulled into it as a

variable

• The validation will simply check to see if #Doors > 4, if so then it will error

out.

• If the validation succeeds then we shall go on and build the car.


Step 1 – Create a NameSpace

Why ? – We want to create out own working area within the model.


Step 2 – Create a Class

Why ? – We are going to create a class so we can instantiate multiple copies of

the same StateMachine.

Think, that the first car we will build is a family car, but later we may wish to

build a sports car. We do not want to rebuild the entire process just because of

a new car. A class allows us to have repeatability and also allows us to inherit

schema from other classes too.

• Create a new class within the MyFirstStateMachine namespace.


Step 3 – Create the Schema

Why ? – We need to lay out the instructions/flow of the StateMachine.

This is very much about planning, thinking about what you want from your

statemachine. Schema – Our schema will be;

• Attribute – Number of Doors

• State – Validate Doors – This will have an On Entry that will perform the validation,

but if the validation fails then it will also have an On Error condition called Error

Doors.

• State – Build the Car, this will execute when the previous state (Validate Doors)

succeeds.


Step 4 – Create the States

There were 3 states in our StateMachine example as follows;

Validate

Doors

On

Error

BuildCar

Error

Doors

Simple Method that outputs to log “Building Car”

Simple Method that outputs to log “Error with

Car”

Method that grabs the Attribute (Number of Doors), checks it is less than <

5, if true then it exits MIQ_OK, otherwise it exits MIQ_ERROR


Check point

To re-cap, you should have a tree view to your StateMachine something like this;

The code behind build_car and error_doors should be something like;


Check point

The code behind validate_doors is slightly more complex and should be something

like;


Step 5 – Create the Instance

The instance will be the object that gets instantiated, here is the instance we will

create, this first time we will call it family car.

Later we are going to create other car types, and extend our use of this

StateMachine, showing how easy, reusable and extensible it can be.


Running the StateMachine

Executing the StateMachine can be done in numerous ways;

Policies – Raise Automation Event

Events – Raise Automation Event

Custom Buttons – Link direct to an Automation Request

Web Services – SOAP call to Automation Request

For this example we shall use a custom button.


Custom Button

Configuration

We will link the button to an

instance in the /System/Request

class called “car”.

Notice that the button Text we

are setting to “Family Car”

Don’t forget to wire your

/System/Request/car instance

to your

/MyFirstStateMachine/Car/fam

ilyCar instance.


Executing the StateMachine!

When the instance was created called “Family Car” the default for Number of Doors

was used, this should have been set to 4 in the schema. Therefore when the Validate

Doors state runs, we will pass with no error.

[----] I, [2013-09-10T12:19:38.351213 #11411:9919ffc] INFO -- : Following Relationship [miqaedb:/MyFirstStateMachine/car/familyCar#create]

[----] I, [2013-09-10T12:19:38.360325 #11411:9919ffc] INFO -- : In State=[validate_doors], invoking [on_entry] method=[validate_doors]

[----] I, [2013-09-10T12:19:38.362838 #11411:9919ffc] INFO -- : Invoking [inline] method [MyFirstStateMachine/car/validate_doors] with inputs

[{}]

[----] I, [2013-09-10T12:19:38.611718 #11411:d7fa0b4] INFO -- : <User-Defined Method> Automate Method Started

[----] I, [2013-09-10T12:19:38.612049 #11411:d7fa0b4] INFO -- : <User-Defined Method> ********* VALIDATE DOORS ***********

[----] I, [2013-09-10T12:19:38.612908 #11411:d7fa0b4] INFO -- : <User-Defined Method> Number of Doors = 4

[----] I, [2013-09-10T12:19:38.613257 #11411:d7fa0b4] INFO -- : <User-Defined Method> Automate Method Ended

[----] I, [2013-09-10T12:19:38.618829 #11411:9919ffc] INFO -- : Method exited with rc=MIQ_OK

[----] I, [2013-09-10T12:19:38.619363 #11411:9919ffc] INFO -- : Next State=[build_car]

[----] I, [2013-09-10T12:19:38.619714 #11411:9919ffc] INFO -- : In State=[build_car], invoking [on_entry] method=[build_car]

[----] I, [2013-09-10T12:19:38.622929 #11411:9919ffc] INFO -- : Invoking [inline] method [MyFirstStateMachine/car/build_car] with inputs [{}]

[----] I, [2013-09-10T12:19:38.911154 #11411:d82b8d0] INFO -- : <User-Defined Method> Automate Method Started

[----] I, [2013-09-10T12:19:38.911524 #11411:d82b8d0] INFO -- : <User-Defined Method> ******* BUILD THE CAR *******

[----] I, [2013-09-10T12:19:38.911843 #11411:d82b8d0] INFO -- : <User-Defined Method> Automate Method Ended


[----] I, [2013-09-10T12:19:38.919520 #11411:9919ffc] INFO -- : Next State=[]

[----] I, [2013-09-10T12:19:38.919667 #11411:9919ffc] INFO -- : Followed Relationship [miqaedb:/MyFirstStateMachine/car/familyCar#create]


Seeing the StateMachine Error outTo cause the StateMachine to error out to the “error_doors” state we simply just increase the

“number_of_doors” attribute to a figure equal to/greater than 5.

[----] I, [2013-09-10T12:51:35.789525 #11411:9919ffc] INFO -- : Following Relationship [miqaedb:/MyFirstStateMachine/car/familyCar#create]

[----] I, [2013-09-10T12:51:35.864078 #11411:9919ffc] INFO -- : In State=[validate_doors], invoking [on_entry] method=[validate_doors]

[----] I, [2013-09-10T12:51:35.866869 #11411:9919ffc] INFO -- : Invoking [inline] method [MyFirstStateMachine/car/validate_doors] with inputs [{}]

[----] I, [2013-09-10T12:51:35.926245 #12128:a922804] INFO -- : Following Relationship [miqaedb:/System/Event/ems_auth_unreachable#create]

[----] I, [2013-09-10T12:51:35.926752 #12128:a922804] INFO -- : Instance [/System/Event/ems_auth_unreachable] not found in MiqAeDatastore - trying

[.missing]

[----] I, [2013-09-10T12:51:35.932561 #12128:a922804] INFO -- : Followed Relationship [miqaedb:/System/Event/ems_auth_unreachable#create]

[----] I, [2013-09-10T12:51:36.290497 #11411:d29a4ac] INFO -- : <User-Defined Method> Automate Method Started

[----] I, [2013-09-10T12:51:36.290871 #11411:d29a4ac] INFO -- : <User-Defined Method> ********* VALIDATE DOORS ***********

[----] I, [2013-09-10T12:51:36.291846 #11411:d29a4ac] INFO -- : <User-Defined Method> Number of Doors = 10

[----] I, [2013-09-10T12:51:36.292288 #11411:d29a4ac] INFO -- : <User-Defined Method> Number of Doors has exceeded the maximum allowed of 4

[----] E, [2013-09-10T12:51:36.389610 #11411:9919ffc] ERROR -- : State=<validate_doors> running on_entry raised exception: <Method exited with

rc=MIQ_STOP>

[----] W, [2013-09-10T12:51:36.389870 #11411:9919ffc] WARN -- : Error in State=[validate_doors]

[----] I, [2013-09-10T12:51:36.390052 #11411:9919ffc] INFO -- : In State=[validate_doors], invoking [on_error] method=[error_doors]

[----] I, [2013-09-10T12:51:36.393388 #11411:9919ffc] INFO -- : Invoking [inline] method [MyFirstStateMachine/car/error_doors] with inputs [{}]

[----] I, [2013-09-10T12:51:36.945727 #11411:d2e3e04] INFO -- : <User-Defined Method> Automate Method Started

[----] I, [2013-09-10T12:51:36.946097 #11411:d2e3e04] INFO -- : <User-Defined Method> ******** ERROR DOORS ********

[----] I, [2013-09-10T12:51:36.946466 #11411:d2e3e04] INFO -- : <User-Defined Method> Automate Method Ended


[----] I, [2013-09-10T12:51:37.073905 #11411:9919ffc] INFO -- : Followed Relationship [miqaedb:/MyFirstStateMachine/car/familyCar#create]


Summary

We created;

Namespace, Class and set the schema.

Wrote the state methods for validate_doors, error_doors & build_car.

Created the instance that a custom button with initiate.

We had two runs of the StateMachine,

Run 1 – Everything succeeded due to the “number_of_doors” < 5

Run 2 – Failure occurred in validate_doors because number_of_doors was > 4, we

observed error_doors was executed.


What Next…?

We will now extend the custom button so we can execute a Family Car or a Sports

Car.

When we select

– Example 2

Step 1 – Create a new Custom Button

Create a new custom bottom with very similar

values to that of your first Custom Button.

Notice that we have added Attribute/Value Pairs.

This will allow the button to pass the attribute

“carType” with the value “sportsCar” to the

Request instance.

Update your previous button “Family Car” with

the Attribute/Value combination, with value as

“familyCar”

– Example 2

Step 2 – Using Variables in Relationships

Using variables to connect two instances together gives us huge flexibility in how we

can fork and control the path of a StateMachine.

Adjust your /System/Request/car instance, so that the relationship to the

/MyFirstStateMachine/familyCar is changed to find an instance that is “${/#carType}”

– Example 2

Step 3 – Create the Sport Car Instance

Create the new instance Sports Car in your /MyFirstStateMachine/Car class.

Set the number of doors to 2.

– Example 2

Try it out

You should now have two buttons configured, Sports Car and Family Car. There is

only one StateMachine setup, but with two instances for the Sports Car and Family

Car executions.

When the Sports Car StateMachine executes, you will see Validate_Doors report only

2 doors, and when Family Car is instantiated you will get 10 doors reported and it

errors out.

Summary – Multiple buttons, single

StateMachine, variablized relationships to

multiple instances.

Why are we here?

Real Cloud Based State Machines

Real Cloud Use-Cases

What sort of automation is possible?

Inbound or Outbound?

First question is

Real Cloud Use-Cases - InboundFrom What?

HelpDesk – We return Insight data back via an agreed standard.

HelpDesk – We are initiated to perform a SmartState scan, to update the

information that they are displaying.

HelpDesk – We are initiated to retire a VM.

HelpDesk – We are initiated to evacuate a host of its VMs

CMDB – The CMDB calls into us for specific data sets that we format and return.

CMDB – The CMDB has raised an event on a failed network, it notifies CF/MIQ to

tag all VMs associated with the failure.

Real Cloud Use-Cases - InboundFrom What?

ServiceCatalog – The catalog reads from us values to populate its dialogs, then

upon submission of the item we are initiated to provision the requested item.

Real Cloud Use-Cases - OutboundTo What?

CMDB– We the CMP deliver inventory data that we are collecting to the webservice

of the CMDB.

HelpDesk – Tickets are automatically opened and closed by the CMP upon tasks

like provisioning, retirement etc..

Placement – Use external systems to provide value to virtual machine placement in

the environment during provisioning.

Quota – Look up in financial systems or other Cloud Costing products for further

data to aid quota evaluation.

IPAM – During provisioning goto an IPAM system to retrieve an IP address for the

instance or virtual machine.

Real Cloud Use-Cases - OutboundTo What?

IPAM – During retirement goto an IPAM system to release an IP address from the

instance or virtual machine back to the pool.

CIP – Work with the Cloud Infrastructure Platform to provision storage, switches or

further hosts.

Not to mention some of the others like;

• DNS (create/delete records),

• DHCP (create/delete reservations),

• Active Directory (domain membership management)

• Foreman/Cobbler/Satellite 5/6 (OS build/assignments)

• Puppet/Radia/SCCM Software Management

Invocation

How to make things happen!

Choices

• Alerts

• Policies

• SoapAPI

• RestAPI

• Buttons

You can also use Simulation to invoke;

• Policies

• Automation Directly

Buttons

Button Groups, group Buttons.

• A button may have a dialog.

• A button must have an image.

• A button can pass messages.

• Attributes/Values can be passed.

The last item is nice as one method can

be called with different attribute/values

from different buttons. Eg, Clone2MS,

Clone2EC2, Clone2vAIR = 1 method,

with a case select.

Policies

Policies can call automation in two

different ways.

1. Invoke a Custom Automation

2. Raise Automation Event

Policies – Invoke a Custom Automation

Policies – Raise an Automation Event

[miqaedb:/System/Event/assigned_company_tag#create]

The raise an automation event, depending on the event you choose to monitor is

raised, first example is “assigned_company_tag” because I selected;

Policies – Raise an Automation EventOther examples…

[miqaedb:/System/Event/PowerOnVM_Task#create]

Or

[miqaedb:/System/Event/PowerOffVM_Task#create]

Policies – Raise an Automation EventFrom your miqaedb:/System/Event/……

You can configure routes to anything you want!

Policies – Invoke a Custom AutomationThis is a lot easier, once you have created your ACTION, with a valid message and

request URI, you are free to create what you specified.

Best Practice – Always set your request to /System/Request

Whilst you can point anywhere, most OOTB functions will look in /System/Request

for the start of an automation task.

Alerts – Management EventVery much the same as Invoke a Custom Automation,

Set the Event Name in the Event.

The create an instance by the same name in the /System/Event class

soapAPI - 1The soapAPI has been superseded in most by the newly added restAPI as found

in ManageIQ Anand and Cloudforms 3.1.

When should I use soapAPI?

When restAPI is NOT available!

About the API

• Read the Integration guide (great info with examples)

• Broken down into 3 different sections

• Insight web services – performs queries against vmdb items

• Control web services – query control related information and perform basic tasks like tagging

• Automate web services – create/query automation and provisioning requests

• Simple Object Access Protocol (SOAP) based Extensible Markup Language (XML)

• Ruby, PowerShell, Perl, JScript, etc…

WSDL Review

• https://<cloudforms-appliance>/vmdbws/wsdl

• There are 3 types of calls

• Query – calls that query CFME for data (I.e. GetEmsList - returns all Management Systems as list objects)

• Action – calls that perform an action (I.e. VmSetTag -applies a tag to a VM by specifying the tag category and name

• Request – calls that create automation and provision requests

Query Example

Query EMS – Ruby#!/usr/bin/env ruby

# CFME Automate Method: GetEmsList.rb

# Require necessary gems

require 'savon'

# Set up Savon client

client = Savon::Client.new do |wsdl, http|

wsdl.document = "https://cloudforms.cloudelicious.com/vmdbws/wsdl"

http.auth.basic 'admin', ‘’smartvm'

http.auth.ssl.verify_mode = :none

end

# Query CFME web-service

response = client.request 'GetEmsList'

# Convert response to hash

response_hash = response.to_hash[:get_ems_list_response][:return]

puts "CFME web-service returned: #{response_hash.inspect}"

# Loop through each management system in the array and log the name and guid

response_hash[:item].each { |key| puts "Found Management System: #{key[:name].inspect} GUID:

#{key[:guid].inspect}" }

Query EMS – Ruby Output

CFME web-service returned: {:item=>[{:guid=>"9f41086a-f488-11e2-9677-001a4a0ba4f3", :name=>"RHEVM-001"},

{:guid=>"035f424e-f48e-11e2-9677-001a4a0ba4f3", :name=>"VMware-001"}],

:"@xmlns:n2"=>"http://schemas.xmlsoap.org/soap/encoding/", :"@n2:array_type"=>"n1:VmdbwsSupport..EmsList[2]",

:"@xsi:type"=>"n2:Array"}

Found Management System: "RHEVM-001" GUID: "9f41086a-f488-11e2-9677-001a4a0ba4f3"

Found Management System: "VMware-001" GUID: "035f424e-f48e-11e2-9677-001a4a0ba4f3"

Action Example

VM Set Tag - Ruby#!/usr/bin/env ruby

# CFME Automate Method: VMSetTag.rb


require 'savon'




http.auth.basic 'admin', ‘smartvm'


end

# Query CFME web-service

response = client.request :vm_set_tag do

soap.body = { 'vmGuid'=>'9badadc8-fe2b-11e2-a507-005056a231cb', 'category'=>'function',

'name'=>'database' }

end

# Convert response to hash

response_hash = response.to_hash[:vm_set_tag_response]

puts "CFME web-service hash returned: #{response_hash.inspect}"

# Loop through each management system in the array and log the name and guid

puts "CFME Returned: #{response_hash[:return].inspect}"}

VM Set Tag – Ruby Output<?xml version="1.0" encoding="UTF-8" ?>

<env:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:xsd="http://www.w3.org/2001/XMLSchema"

xmlns:env="http://schemas.xmlsoap.org/soap/envelope/">

<env:Body>

<n1:VmSetTagResponse env:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"

xmlns:n1="urn:ActionWebService">

<return xsi:type="xsd:boolean">true</return>

</n1:VmSetTagResponse>

</env:Body>

</env:Envelope>

CFME web-service hash returned: {:return=>true,

:"@env:encoding_style"=>"http://schemas.xmlsoap.org/soap/encoding/",

:"@xmlns:n1"=>"urn:ActionWebService"}

CFME Returned: true

Request Example -Automation

Create Automation Request

• This method initiates an automation request. It can be

used to drive an automation workflow and provide

feedback to the requester.

• Execute any instance or SateMachine you want!

• Input parameters• version

• uri_parts

• Parameters – these guys show up in $evm.root

• requester

Create Automation Request - Ruby

#!/usr/bin/env ruby

# CreateAutomationRequest.rb


require 'savon'




http.auth.basic 'admin', 'smartvm'


end

# Build has of paramters

body_hash = {}

body_hash['version'] = '1.1'

body_hash['uri_parts'] = "namespace=Sample|class=Methods|instance=InspectMe|message=create"

body_hash['parameters'] = 'parm1=parameter1|parm2=parameter2'

body_hash['requester'] = "auto_approve=true"

response = client.request :create_automation_request do |soap|

soap.body = body_hash

end

request_hash = response.to_hash

puts "Request Returned: #{request_hash.inspect}"

puts "Automation Request Id: #{request_hash[:create_automation_request_response][:return].inspect}"

exit

Create Automation Request – Ruby Output

<?xml version="1.0" encoding="UTF-8" ?>

<env:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:xsd="http://www.w3.org/2001/XMLSchema"

xmlns:env="http://schemas.xmlsoap.org/soap/envelope/">

<env:Body>

<n1:CreateAutomationRequestResponse

env:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"

xmlns:n1="urn:ActionWebService">

<return xsi:type="xsd:string">919000000000071</return>

</n1:CreateAutomationRequestResponse>

</env:Body>

</env:Envelope>

Request Returned: {:create_automation_request_response=>{:return=>"919000000000071",

:"@env:encoding_style"=>"http://schemas.xmlsoap.org/soap/encoding/",

:"@xmlns:n1"=>"urn:ActionWebService"}}

Automation Request Id: "919000000000071"

Request Example -Provisioning

VM Provision Request

• VmProvisionRequest – This initiates a VM provision

request and returns an request id object that provides

feedback

• EVMProvisionRequestEx – This initiates a VM provision

request and returns true|false with no added feedback

• VmProvisionRequest Input parameters• version

• templateFields

• vmFields

• requester

• tags

• Options

• Dialogs are the keys to success

VM Provision Request - Ruby#!/usr/bin/env ruby

# VMProvisionRequest.rb


require 'savon'




http.auth.basic 'admin', ‘smartvm'


end

# Build hash of paramters

body_hash = {}

body_hash['version'] = '1.1'

body_hash['templateFields'] = "name=rhel63|request_type=template|guid=cb73axb8-f46f-11e2-ba2d-005056a231cb"

body_hash['vmFields'] = 'vm_name=changeme|cores_per_socket=1|vm_memory=1024|vm_auto_start=true'

body_hash['requester'] = "user_name=admin|owner_last_name=Lastname|owner_first_name=Firstname"

body_hash['tags'] = "environment=dev|function=database"

body_hash['options'] = { 'values' => 'parm1=parameter1|parm2=parameter2', 'miq_custom_attributes' => "", 'ems_custom_attributes'

=> "" }

response = client.request :vm_provision_request do |soap|

soap.body = body_hash

end

request_hash = response.to_hash

puts "Request Returned: #{request_hash.inspect}"

puts "Provision Request Id: #{request_hash[:vm_provision_request_response][:return][:id].inspect}”

VM Provision Request – Ruby Output

VM Request Returned: {:vm_provision_request_response=>{:return=>{:id=>"919000000000074",

:description=>"Provision from [rhel63] to [cfmedev###]", :approval_state=>"pending_approval"….(Output is too

large to show all of it)

VM Provision Request Id: "919000000000074"

Design Summit - Intro to State Machines - John Hardy

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Transcript of Design Summit - Intro to State Machines - John Hardy