Tag: update

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Run powershell command on virtual machines scale set

Azure Virtual Machine Scale Sets let you create and manage a group of load balanced VMs. The number of VM instances can automatically increase or decrease in response to demand or a defined schedule. Scale sets are commonly used for critical infrastructure like Kubernetes and service fabric. In this guide we will examine how we can perform an action massively on all nodes of the vmss.

The below vmss is composed of windows virtual machines that belong to an azure resource.

When you need to update all the nodes of vmss with a specific action, for instance to install a powershell module, you will need to use the run-command.

az vmss run-command | Microsoft Learn

First you will need to get all instances ids as they are a parameter for the next commands.

az vmss list-instances -n $vmss_name -g $rg_name --query "[].id" --output tsv

The output should be similar with the below.

/subscriptions/ID/resourceGroups/rg/providers/Microsoft.Compute/virtualMachineScaleSets/vmssname/virtualMachines/0
/subscriptions/ID/resourceGroups/rg/providers/Microsoft.Compute/virtualMachineScaleSets/vmssname/virtualMachines/1
/subscriptions/ID/resourceGroups/rg/providers/Microsoft.Compute/virtualMachineScaleSets/vmssname/virtualMachines/2

Then you can execute a powershell script on the vmss nodes by specifying the node id of the previous command and the resource group name along with the vmss name.

az vmss run-command invoke  --command-id RunPowerShellScript -n $vmss_name -g $rg_name --scripts 'hostname' --instance-id 0

Youtube video:

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Update variable group using Azure DevOps rest API – pipeline example

Following my previous article about how to update a variable group using POSTMAN, I will now document how to implement the same behavior through a pipeline.

Update variable group using Azure DevOps rest API – POSTMAN

First things first you will need a PAT. I have included this PAT in a different variable group than the one that I will update. this is because when you update the variable group, all the variables that are inside will get lost. If you need to retain them, you should have to get them first and then add them again on the variable group.

For this reason I have created a variable group named token-group which holds my PAT. I also made this variable a secret.

The variable group that I will update has the name of var-group and the id of 5.

The pipeline includes two tasks. The first task will loop through the variables on the group and print them out. The second task will update the variable group based on the JSON that you provided. You should change your ORG and project URLs.

trigger:
– none
pr: none
pool:
vmImage: ubuntu-latest
variables:
– group: token-group
steps:
– task: PowerShell@2
displayName: Get variables from variable-group
inputs:
targetType: 'inline'
script: |
$connectionToken="$(PAT)"
$base64AuthInfo= [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes(":$($connectionToken)"))
$URL = "https://dev.azure.com/geralexgr/test-project/_apis/distributedtask/variablegroups?groupIds=5&api-version=7.1-preview.1"
$Result = Invoke-RestMethod -Uri $URL -Headers @{authorization = "Basic $base64AuthInfo"} -Method Get
$Variable = $Result.value.variables | ConvertTo-Json -Depth 100
Write-Host $Variable
– task: PowerShell@2
displayName: add variables on variable-group
inputs:
targetType: 'inline'
script: |
$connectionToken="$(PAT)"
$base64AuthInfo= [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes(":$($connectionToken)"))
$URL = "https://dev.azure.com/GeralexGR/test-project/_apis/distributedtask/variablegroups/5?api-version=5.1-preview.1"
$body = '{"id":5,"type":"Vsts","name":"var-group","variables":{"rest-var1":{"isSecret":false,"value":"rest-var-value-1"},"rest-var2":{"isSecret":false,"value":"rest-var-value-2"},"rest-var3":{"isSecret":false,"value":"rest-var-value-3"}}}'
$Result = Invoke-RestMethod -Uri $URL -Headers @{authorization = "Basic $base64AuthInfo"} -Method Put -Body $body -ContentType "application/json"
$Variable = $Result.value.variables | ConvertTo-Json -Depth 100
Write-Host $Variable
view raw update-variable-group-powershell-azure-devops hosted with ❤ by GitHub

After running the pipeline you will notice a null output on the update of the variable group. This is the requested result and as task has not failed your var group will get updated.

Variables inside json

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Update variable group using Azure DevOps rest API – POSTMAN

I was struggling to update a variable group using the Azure DevOps Rest API. In this article I will document the procedure using POSTMAN.

First things first you should create a PAT in order to interact with the API. If you do not know how to create such a thing you should read my previous article about running a build through a REST api on which I documented also the creation of a PAT.

Trigger Azure Devops build pipelines using REST API

Then you will need to add the access token under authorization tab of POSTMAN using Type Basic Auth. The PAT should be added as plain text.

Then you will need to add Content-Type as application/json under Headers.

Then you will have to create your URL. This should be of the format:

https://dev.azure.com/Organization/project/_apis/distributedtask/variablegroups/groupVariableID?api-version=5.1-preview.1

Important: You should use the version=5.1-preview.1. If you use the latest version you will notice an error on the call. This is a bug that has not been fixed as I found online.

In my example I wanted to update the variable group with the ID 5 and add a variable named new-var. The body of your request should be like below. Keep in mind that we use the PUT HTTP verb to update the variable group. This means everything that is inside the variable group will be discarded. If you followed all the steps correctly you will notice the below output JSON. This should indicate success on the procedure.

Lastly you can locate your new variable inside the variable group.

Variablegroups – Update – REST API (Azure DevOps Task Agent) | Microsoft Docs

Video tutorial on YouTube:

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Automatically update your GitHub repositories with a powershell script

Developers often have a lot of repositories stored on their local machines. These repositories get updated from other developers and they stay outdated. In many cases developers forget to fetch and pull the latest changes on those repositories and when they commit code, the IDE will notify of the new changes. When this is the case, the commit will get an non explanatory message as the latest of the commit and you will have to navigate on the actual commit to verify the changes and commit message.

Commit message
Merge branch test/v3.0.0 of https://github.com/org/repository

In order to resolve this issue, you can create a powershell script that can automatically fetch the latest changes of your local repositories. You will need to change your repositories base location.

#change your github location
$github_directory = "C:\Users\galexiou\Documents\GitHub"
Get-ChildItem $github_directory | ForEach-Object {
if($_.Attributes -eq "Directory")
{
Write-Host $_.FullName
Set-Location $_.FullName
git fetch
git pull
}
}
view raw github-update.ps1 hosted with ❤ by GitHub

As you can see from the output below this script will go and fetch the latest changes on the repositories that have been updated.

You can also create a cron job or an automated windows task in order to run this job automatically on computer startup or on your work schedule start. For example

On task scheduler press create task

and select your triggers (when this task will run) along with the action. This will be the run of the powershell script. On the argument you must specify the -File location (where you stored your powershell script).