What is the REST equivalent of the OnTAP CLI command "cluster ring show"

[SCOTT_LINDLEY]

Looking to query the "epoch" values for the mgmt, vldb, vifmgr, bcomd, crs, availd units via the OnTAP REST API. Doing this as part of a "health check" type process.

Please advise.

[mbeattie · Accepted solution]

Hi Scott,

I don't believe there is a public API for this command. You will need to to use the private REST CLI for this. Please see the code below. I tested this successfully in a lab:

Param(
   [Parameter(Mandatory = $True, HelpMessage = "The cluster name or IP Address")]
   [String]$Cluster,
   [Parameter(Mandatory = $True, HelpMessage = "The Credentials to authenticate to the cluster")]
   [System.Management.Automation.PSCredential]$Credential
)
#'------------------------------------------------------------------------------
#'Set the certificate policy and TLS version.
#'------------------------------------------------------------------------------
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]::SecurityProtocol  = [System.Net.SecurityProtocolType]'Tls12'
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy
#'------------------------------------------------------------------------------
Function Get-NcAuthorization{
   [Alias("Get-NcAuth")]
   [CmdletBinding()]
   Param(
      [Parameter(Mandatory = $True, HelpMessage = "The Credential to authenticate to the cluster")]
      [ValidateNotNullOrEmpty()]
      [System.Management.Automation.PSCredential]$Credential
   )
   #'---------------------------------------------------------------------------
   #'Set the authentication header to connect to the cluster.
   #'---------------------------------------------------------------------------
   $auth    = [System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes($Credential.UserName + ':' + $Credential.GetNetworkCredential().Password))
   $headers = @{
      "Authorization" = "Basic $auth"
      "Accept"        = "application/json"
      "Content-Type"  = "application/json"
   }
   Return $headers;
}#'End Function Get-NcAuthorization.
#'------------------------------------------------------------------------------
#'Invoke the command via the private REST CLI.
#'------------------------------------------------------------------------------
$headers         = Get-NcAuth -Credential $Credential
[String]$command = "set diag`;cluster ring show -fields unitname, epoch, db-epoch, db-trnxs, master, online"
[String]$uri     = "https://$Cluster/api/private/cli/cluster/ring?fields=unitname,epoch,db-epoch,db-trnxs,master,online"
Write-Host "Executing Command`: $command"
Try{
   $response = Invoke-RestMethod -Method GET -Uri $uri -Headers $headers -ErrorAction Stop
}Catch{
   Write-Warning -Message $("Failed Executing Command`: $command. Error " + $_.Exception.Message)
   Break;
}
#'------------------------------------------------------------------------------
#'Display the records.
#'------------------------------------------------------------------------------
If($Null -eq $response -Or $response.num_records -eq 0){
   Write-Warning -Message "No records were returned from executing command`: $command"
}Else{
   $response.records
}
#'------------------------------------------------------------------------------

To invoke the code use the following syntax:

PS C:\Scripts\PowerShell\Projects\ClusterRingShow> $credential = Get-Credential -Credential admin

Windows PowerShell credential request
Enter your credentials.
Password for user admin: ********************

PS C:\Scripts\PowerShell\Projects\ClusterRingShow> .\ClusterRingShow.ps1 -Cluster 10.20.30.40 -Credential $credential

Hope that helps

/Matt

[SCOTT_LINDLEY]

Thanks, somehow I didn't think about the private REST CLI. I really prefer using a publicly published and long-term supported endpoint, but this is still better than the "screen-scraping" I've been doing. I translated the above into a format that my Perl module will understand and implemented it, I'll stick with it until (hopefully) NetApp implements a public endpoint.

I'm more than a little disappointed that there isn't yet a 1:1 parity between CLI commands and REST endpoints. I seem to recall that this was one of the original design goals but perhaps staffing cuts got in the way. It's distressing to note that the ZAPI/OnTAPi calls were far closer to 1:1 than REST is, especially given that REST has been "in the works" as long as it has. That and I've found far more bugs in the existing REST endpoints than I did in the well over 10 years I spent using ZAPI.

Well, I guess that I got my rant in for the day. 🙂 I'll mark the post as "Accept as Solution" and hope that the NetApp Engineering Team gets wind of this and makes sure it's on the implementation list.

Thanks for the assistance!

[mbeattie]

Hi Scott,

Glad that solution works for you (even if not ideal it's definitely better than CLI screen scraping). I can certainly empathize with your viewpoint and will definitely forward your feedback. Thanks 

/Matt