Create a task in Task Scheduler using PowerShell Script

 

We all know how to create a task in Task Scheduler. When we create a task we need to add many settings to run the task periodically as per the settings. But what to do when we want to create the same task in multiple environments in your project. Creating them manually is a tedious task and as usual Microsoft heard you and provided the option to configure the tasks using the mighty powerful “PowerShell script”. But with one exception that this is available for Windows 8.1 and higher and Windows 2012.

To demonstrate the powerful PowerShell capability, let’s dive in.

I want to create the following task in order to run a testapp.exe periodically.

We want to accomplish the following:

Create a new task and the task name should be “Test Task” and it should run as “NT Authority”.

Figure 1: General properties

Trigger tab should be set with the settings as

1. It should run daily and start date is 3/1/2016 and at 12:00:00 AM and it should recur for every 1 day.

2. Also the task should repeat every one hour and it should run for a duration of 1 hour.

Figure 2: Trigger settings

The action tab should be configured to run the program “TestApp.exe” which is located in C Drive.

Figure 3: Action settings

Our settings tab should be configured with the following settings:

1. Allow task to run on demand

2. If the task fails, restart every 1 hour and it should attempt restarting for 3 times

3. If the task runs for more than 1 hour then stop it and also force it to be stopped if it’s not stopping

Figure 4: Setting tab

Let us write the PowerShell script to accomplish the above mentioned task in the task scheduler. Here are the steps:

Step 1: Name of the task.

Create a variable and assign task name. In our case it should be “Test Task”.

# Name of Task to create $taskName = "Test Task"

Step 2: Set the credentials.

Create two more variables and assign it the credentials.

In our case, we want the task to run as “NT Authority” and password is not required. But if you want to run with a particular account username and password, create username and password variables and assign them the values.

# UserName to run task as $user = "NT AUTHORITY\SYSTEM" # Password for above user #$password = "userPassword" Uncomment this line if you need to set up password

Step 3: Now create the task

In our case we do not have any arguments. But if you need to add then uncomment the $argument line and set the $argumentvalue

$action defines the action to perform i.e. to execute the exe file and uncomment the argument parameter after the exe if you need to add it.

$trigger defines the trigger settings

$settings defines the settings settings

#$argument = "-Noninteractive -Noprofile -Command &'" + $argumentvalue + "'" $action = New-ScheduledTaskAction -Execute "C:\MyTestApp.exe" #-Argument $argument $trigger = New-ScheduledTaskTrigger -Daily -At 12am $settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 60) $settings.RestartCount=3 $settings.RestartInterval = 'PT01H'

Step 4: Get the instance of scheduled task by specifying New-ScheduledTask command and set the action and trigger and register the scheduled task.

$inputObject = New-ScheduledTask -Action $action -Trigger $trigger -Settings $settings Register-ScheduledTask -TaskName $taskName -InputObject $inputObject -User $user

Step 5: Now wait for 5 seconds and then set the trigger repetition interval and duration and set the scheduled task.

Start-Sleep -Seconds 5 $t = get-scheduledtask -TaskName $taskName $t.Triggers.repetition.Duration = 'PT60M' $t.Triggers.repetition.Interval = 'PT01H' $t | Set-ScheduledTask

The completed script will look as below:

# Name of Task to create $taskName = "Test Task" #$argumentvalue = "first" # UserName to run the task created as $user = "NT AUTHORITY\SYSTEM" # Password for above user #$password = "userPassword" # Create Task #$argument = "-Noninteractive -Noprofile -Command &'" + $argumentvalue + "'" $action = New-ScheduledTaskAction -Execute "C:\MyTestApp.exe" #-Argument $argument $trigger = New-ScheduledTaskTrigger -Daily -At 12am $settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 60) $settings.RestartCount=3 $settings.RestartInterval = 'PT01H' $inputObject = New-ScheduledTask -Action $action -Trigger $trigger -Settings $settings Register-ScheduledTask -TaskName $taskName -InputObject $inputObject -User $user Start-Sleep -Seconds 5 $t = get-scheduledtask -TaskName $taskName $t.Triggers.repetition.Duration = 'PT60M' $t.Triggers.repetition.Interval = 'PT01H' $t | Set-ScheduledTask

The above few lines of code will do the job of creating the task with the same settings and you can automate it so that you can run wherever you want.

When you run the script you should see following screen:

Figure 5: Script execution

A trick if you do not know how to set the parameters for the commands. Go to “Windows PowerShell ISE” and run as administrator if needed and type the command that you want to add to the script by using the command window as below:

Figure 6: Command window

You can find more commands in the MSDN and hope this article is useful for creating a basic task in the task scheduler using the PowerShell script. With the growth of automation and agile methodologies everywhere, it would be beneficial for the teams to explore the PowerShell more and more and to replace your manual tasks wherever it is possible.

IaaS, Internal Load Balancing (ILB) in AZURE

 

When we speak of cloud we always think of Platform as a service (PaaS), Infrastructure as a service (IaaS) and Software as a Service (SaaS).

In this article we discuss about the IaaS and how to scale websites or applications running in virtual machines that forms a part of IaaS infrastructure. In simple terms, IaaS means we buy a storage from cloud provider and we deploy or create our own machines or provider’s pre-built Images and we control the infrastructure like operating systems, ports and all the software installed on the machines.

Common scenarios for opting to IaaS is when a company wants to setup a testing environment for a particular period of time, or a dev team is doing some R&D and needs a machine with particular configuration for temporary purpose and later those machines will be decommissioned. This way, we do not need to invest on the infrastructure that we use only for a particular amount of time. But this may not be correct always. It always depends upon the requirements.

Before jumping into the details on how to create ILBs, let us try to understand how ILBs differ from typical load balances (F5s).

F5 Load Balancers:

Figure 1: F5 Load balancers (Firewall sitting between is optional)

F5 load balancers primarily sit between clients and the hosts that provide the services.

F5 load balancers typically are used when we expose our services to the outside of our company network. This does not mean they will not be used within the company network. But when we deploy our services or applications in ON PREMISE and want to expose the services/applications to the outside world.

The typical transaction flow will be as follows:

Let us make the following assumptions to understand the transaction flow:

Load Balancer URL – 192.168.89.1

Web Server 1 – 192.168.77.76

Web server 2 – 192.168.77.77 and the service name - weatherinfo

Figure 2: Load balancing flow between the clients and the hosts through Load Balancers

Load Balancers uses the health monitoring mechanism to periodically check the health of the hosts and accordingly will forward the request to the host. A simple health check mechanism will be PINGING to the server and checking for the response. Next level mechanism is to deploy the health check application that provides the health of the intended service and gives accurate information to the Load balancer if it has to forward a request or not.

If health of all the hosts are good then LBs use Round Robin as a simple mechanisms to complex algorithms based on connection counts, host utilization and other important criterion to decide which host needs to be responding to a particular request.

Internal Load Balancers (ILBs):

ILBs comes into picture when we talk about Cloud services created in AZURE, AWS and so on. Unlike Load balancers, ILBs supports the following types of load balancing:

- Load balancing between the virtual machines within a cloud service.

- Load balancing between virtual machines between different cloud services that are contained within a virtual network.

In this article, we would be going through the first type i.e. load balancing of incoming internet traffic to different virtual machines within a cloud service. This is also called as Network Level type of load balancing.

Figure 3: ILB with VMs

Let’s go through the steps to create the ILB by creating two virtual machines and creating a load balanced set to load balance the two VMs. There is no direct way to create Load Balanced set in portal and it should be done as a part of creation of VMs.

Step 1: Create a cloud service first so that we can add the VMs to the cloud service. (I am not using portal instead I am using manage.windowsazure.com for this article)

Figure 4: Creation of cloud service

2. Create a Virtual machine.

Figure 5: Selecting Compute à Virtual Machine

Figure 6: Choosing the image (Windows server 2012 R2 Datacenter)

Figure 7: VM Configuration

Figure 8: Added HTTP and HTTPS endpoints by clicking “Add” button on the bottom of the page

Step 3: Now select HTTPS endpoint and click edit icon and create a LOAD-BALANCED SET. I want to load balance the VMs through the port 443.

Figure 9: Editing the HTTPS endpoint to create a Load Balanced set

Figure 10: Setting the load-balanced set details

In the figure 9, Probe Protocol indicates which protocol does the load balancer should use to probe the health of the VM and the port denotes the port to be used, Probe Interval tells the load balancer to attempt a TCP connect to the specified probe port for every 15 seconds. If it did not get TCP ACK back for two times (Number of probes), then it will consider that the node is offline and will stop traffic to that node.

Figure 11: Check the load-balanced set is created on HTTPS endpoint 443.

Now create another VM by following the above steps and then add a HTTPS endpoint and select option “Add an endpoint to an Existing load balanced set” and proceed.

Figure 12: Adding an endpoint to an existing load balanced set

After completing the above steps, create a website in IIS for both the VMs and expose the sites on port 443. I have created a website with a simple html page in both the VMs. For VM1, the html displays the text “This is from WEBMAC1” and for VM2 it displays “This is from WEBMAC2”.

Now when I browse

Figure 13: Website page

Now browse the cloud service and you should see the web page randomly displaying the messages from the both the boxes. Try to stop the website in one of the box or stop the VM and see if you are still able to browse. It should not be trying to hit the stopped VM or website.

Additional points:

In the figure 6 while creating VMs, I did not add “Availability Set”. But if you create one and assign it to both the VMs, Windows Azure will make sure that the two VMs are created on separate racks in the data center. This will also help during the host patching by not taking down all the nodes at same time and makes sure that your application will always run. This is most critical in any organization that needs 24/7 availability.

Also while configuring load balanced set, I have configured on TCP port. But you can do the same with HTTP port. This will allow you to write your own website or app that informs the health of the application which is more accurate than hitting the TCP port. You can add your custom logic to tell if the application is healthy. For example, if your application is not able to talk to database from the hosted server, you do not want the requests to be forwarded to that server and thus you can eliminate error screens for clients.

One more thing is that I have used same port 443 for both application and probing port. In real time situations they need not be or will not be same. Also for HTTP probes make sure that the application on that port does not support any authentication mechanism. It should respond without providing any credentials.

In real time scenarios, we will not follow the manual steps mentioned in the article. It will be easier to perform these in automated fashion using Powershell. You can check MSDN for more information on using Powershell scripts.