Sunday, March 11, 2018

PowerShell quick start guide

This post is for all those who would like to kickstart and learn PowerShell from the very basic level. When I started learning PowerShell I wrote few articles so that it will be helpful for folks who are looking forward to 'how to start and learn it' and I can also refer to it whenever I need. Here in this post, I am just putting all of them together in proper order so that anyone can easily make use of it.

PowerShell 101 blog series

Friday, March 9, 2018

Infrastructure testing using Pester - Part 2

In my previous post I explained briefly about the basics of using Pester to test and validate your infrastructure. This article is about how to create/ output custom messages on Pester test failures. Let's have a look at the below example.

#example_test.ps1
Describe "Verify drive D" {
    Context "Check file system type and AUS" {
        It "Test 1: Should be NTFS" {
            $drive_stat = fsutil fsinfo statistics D:
            ($drive_stat[0]) -match 'File System Type :\s+NTFS' | Should Be $true
        }
        It "Test 2: Should have 4K AUS" {
            $AUS_stat = fsutil fsinfo refsinfo D:
            ($AUS_stat[8]) -match 'Bytes Per Cluster :\s+4096' | Should Be $true
        }
    }
}

Describe "Verify Hyper-V vSwitch" {
    Context "Check for Corp vSwitch, its type and connected NIC" {
       
        $check = Get-VMSwitch | where name -eq Corp

        It "Test 3: Corp vSwitch should be present" {
            ($check.Name) | Should -BeExactly "Corp"
        }
        It "Test 4: Corp vSwitch type should be Internal" {
            ($check.SwitchType) | Should -BeExactly "Internal"  
        }
    }
}


I get the following output, when I run it against one of my test machine.


The above screenshot shows, Test 1 and Test 4 is failed. Eventhough you get the error message, some users/ admins prefer to have a custom message when a test fails. So that it will be very easy to troubleshoot for the one who is validating the infrastructure. To save custom messages for each test, I am using a hash table, and if a test is found to be failed, it will pick the respective custom message from the hash table and displays it and the end of the test. Here I created a new ps1 file as below.

#invoke_test.ps1
$test = Invoke-Pester .\example_test.ps1 -PassThru

$failmsg_table = @{
    "Test 1: Should be NTFS"                        = "Test 1: Failed because the filesystem of drive D is not NTFS"
    "Test 2: Should have 4K AUS"                    = "Test 2: Failed because the AUS of drive D is not 4K"
    "Test 3: Corp vSwitch should be present"        = "Test 3: Failed becuase Corp vSwitch is not present"
    "Test 4: Corp vSwitch type should be Internal"  = "Test 4: Failed because Corp vSwitch type is not Internal"
}

for ($i=0; $i -le $test.TotalCount; $i++){
    if ($test.TestResult[$i].Result -eq "Failed") {
        write-output $failmsg_table[$($test.TestResult[$i].Name)]
    }
}



When I execute "invoke_test.ps1", it invokes "example_test.ps1" and the output is saved to variable "test". The hash table has the list of tests and the corresponding custom message. If any of the "TestResult" is Failed, the corresponding custom message will be displayed. Sample output screenshot is given below.


 Hope this was useful. Cheers!

Wednesday, March 7, 2018

Working with ScaleIO REST API using PowerShell - Part 2

In my previous post, I explained how to connect and authenticate with ScaleIO REST API, and use Invoke-RestMethod. In this article, I will explain how to query selected statistics/ properties with POST method. 

First, you have to define the set of properties that you would like to query, and then pass it to "invoke-restmethod". You can get the list of available properties of the respective object from the ScaleIO REST API Reference Guide. 

Example 1: Query and collect MDM cluster information
Here I am collecting the below-mentioned properties of "MDMCluster" object. 

#selected properties to query

$param1 = @'
{
    "properties":["name", "clusterMode", "master", "clusterState", "virtualIps"]
}
'@

#invoke-restmethod with respective uri

$MDM_cluster_stats = (Invoke-RestMethod -Uri "https://192.168.11.15:443/api/instances/System/queryMdmCluster " -Body $param1 -ContentType "application/json" -Headers $ScaleIOAuthHeaders -Method Post)

#organize output in a hash table

$mdm_props = @{

    'Cluster name'      = ($MDM_cluster_stats).name
    'Mode'              = ($MDM_cluster_stats).clusterMode
    'Cluster state'     = ($MDM_cluster_stats).clusterState
    'Master MDM IP'     = ($MDM_cluster_stats.master).managementIPs[0]
    'Cluster VIP01'     = ($MDM_cluster_stats).virtualIps[0]
    'Cluster VIP02'     = ($MDM_cluster_stats).virtualIps[1]
}

Write-Output $mdm_props

#sample output screenshot given below


Example 2: Query and collect overall ScaleIO system capacity details
Here I am collecting some properties of "System Statistics" object. 

#selected properties to query

$param2 = @'
{
    "properties":["maxCapacityInKb", "capacityInUseInKb", "spareCapacityInKb", "failedCapacityInKb", "degradedFailedCapacityInKb"]
}
'@

#invoke-restmethod with respective uri

$system_overall_stats = (Invoke-RestMethod -uri "https://192.168.11.15:443/api/types/System/instances/action/querySelectedStatistics " -Body $param2 -ContentType "application/json" -Headers $ScaleIOAuthHeaders -Method Post)

#organize output in a hash table


$system_capacity_props = @{

    "System max capacity (TB)"                = (($system_overall_stats.maxCapacityInKb)/1024/1024/1024)
    "System capacity in use (TB)"             = (($system_overall_stats.capacityInUseInKb)/1024/1024/1024)
    "System spare capacity (TB)"              = (($system_overall_stats.spareCapacityInKb)/1024/1024/1024)
    "System failed capacity (TB)"             = (($system_overall_stats.failedCapacityInKb)/1024/1024/1024)
    "System degraded failed capacity (TB)"    = (($system_overall_stats.degradedFailedCapacityInKb)/1024/1024/1024)
}

Write-Output $system_capacity_props

#sample output screenshot given below


Hope this was useful. Please refer Dell EMC ScaleIO Ready Node Version 2.5 API Reference Guide for more details.

Wednesday, February 28, 2018

Working with Dell EMC PowerFlex REST API using PowerShell - Part 1

In this article, I will explain briefly how to work with REST API exposed by PowerFlex (formerly known as ScaleIO and VxFlex OS Software) using PowerShell to manage/ monitor your PowerFlex cluster. The PowerFlex REST API is served from the PowerFlex Gateway which allows querying information and performing actions related to PowerFlex software components. PowerFlex Gateway connects and queries master MDM, reformats the results in a RESTful manner, and passes it to a REST client.

Access to the API requires a login using Gateway username and password. A successful login returns a token, and you can use this token for later authentications for other requests. The responses or results returned are in JSON format. In the following sections, I will explain how to use PowerShell to query PowerFlex REST API and obtain relevant results.  

PowerShell uses Invoke-RestMethod cmdlet which sends HTTP/ HTTPS requests to REST web services that return rich structured data. PowerShell will format the response based on the data type. For JSON PowerShell converts the response content to objects. 

Step 1: Authentication and token generation

#Note: 192.168.11.15 is the IP of PowerFlex Gateway
$User = Read-Host -Prompt "Please enter username"
$SecurePassword = Read-Host -Prompt "Enter Password for user $user" AsSecureString
$Credentials = New-Object System.Management.Automation.PSCredential ($user,$Securepassword)

#HTTPS Get request is invoked with credentials for authentication
$Token = Invoke-RestMethod -Uri "https://192.168.11.15:443/api/login" -Method Get -Credential $Credentials

Step 2: Create header with the token
$auth = [System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes(':'+$Token))
$global:PowerFlexAuthHeaders = @{'Authorization' = "Basic $auth"
'Content-Type' = "application/json" }

Step 3: Invoke-RestMethod

#Query all alerts in the system
$alerts = (Invoke-RestMethod -Uri "https://192.168.11.15:443/api/types/Alert/instances/" -Method Get -Headers $PowerFlexAuthHeaders)

#Query all SDSs in a PD
$all_SDS = (Invoke-RestMethod -Uri "https://192.168.11.15:443/api/instances/ProtectionDomain::3ce4af5f00000000/relationships/Sds " -Method Get -Headers $PowerFlexAuthHeaders)

#Query a specified PD
$pd01 = (Invoke-RestMethod -Uri "https://192.168.11.15:443/api/instances/ProtectionDomain::3ce4af5f00000000 " -Method Get -Headers $PowerFlexAuthHeaders)
#Query statistics of a specified PD
$pd01_stats = (Invoke-RestMethod -Uri "https://192.168.11.15:443/api/instances/ProtectionDomain::3ce4af5f00000000/relationships/Statistics " -Method Get -Headers $PowerFlexAuthHeaders)

Hope this was useful. Refer to the PowerFlex REST API Reference Guide for more details.
In the next article, I will explain how to query selected statistics/ parameters with POST method which will help you to
create custom monitoring scripts for your PowerFlex clusters.

Note:
If you are getting the below error while trying to create the token during step 1, please add the below lines of code to the
start of your script.

"Invoke-RestMethod : The underlying connection was closed: An unexpected error occurred on a send."

#Solution to above error!
add-type @"
    using System.Net;
    using System.Security.Cryptography.X509Certificates;
    public class TrustAllCertsPolicy : ICertificatePolicy {
        public bool CheckValidationResult(
            ServicePoint srvPoint, X509Certificate certificate,
            WebRequest request, int certificateProblem) {
            return true;
        }
    }
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls12 -bor [System.Net.SecurityProtocolType]::Tls11