mercoledì 23 aprile 2014

VMware: Automate the manual deployment of vCloud Agent

While creating provider VDCs in vCloud Director sometimes occurs that not every host is being prepared successfully due to various reasons: something configured incorrectly, cannot place host into maintenance mode, cannot communicate with host, etc. This incapability to correctly dialogue with ESXi hosts leads to the missing deployment of vCloud agent on the hosts belonging to a provider VDC.

The best way to solve this is to fix the underlying problem. Let's be clear: when everything is fine vCloud Director agent deployment works smooth but when something is not the host preparation may become quite a pita. A way to fix this is to proceed with a manual deployment of vCloud agent but, as you reckon, this is quite uncomfortable when dealing with a large number of ESXi hosts.

Today's post goal is to provide a PowerCLI script that allows you to automate the manual process of vCloud agent deployment as well as a mass agent upgrade.

The following script will:

-Connect to a vCenter Server
-Download to your local machine the specified vCloud agent version from vCloud Director virtual machine
-For each host on which you need to install vCloud agent script will:
    -Place host into maintenance mode
    -Enable SSH
    -Check whether vCloud agent is installed or not. If already installed uninstall it first
    -Transfer vCloud agent over to ESXi host using Putty Secure Copy
    -Install vCloud agent
    -Disable SSH
    -Exit maintenance mode
Once vCloud agent is successfully installed ESXi host is seen as correctly prepared from vCloud Director.

This is the PowerCLI code. As always you can also find it in my GitHub repository. Automate vCloud Agent Deployment.ps1

Code is quite well commented but let me spend a few words on some cmdlets.

Initial part comprises variable declaration. $FileVcloudAgent is the version of vCloud agent that will be downloaded from vCloud Director virtual machine and later installed on all specified ESXi hosts. In the script I use file. As name states this version is for ESXi 5.1. If you have different ESXi versions you MUST choose the appropriate ones, like if you are using ESXi 5.5 (with vCloud Director 5.5) or in case of ESXi 5.0, etc.

$puttyScpLocation points to the location of Putty Secure Copy (pscp.exe) that can be downloaded from here and must be placed somewhere on your local machine. Putty Secure Copy is used to copy vCloud agent over to /tmp/ folder of each ESXi host.

Copy-VMGuestFile is a PowerCLI cmdlet used to download specified file from vCloud Director virtual machine to your local machine. -GuestToLocal parameter states that we are downloading files from a VM. Au contraire -LocalToGuest would have been used.

Crucial commands of script above are the VIB uninstall/install ones. To perform a VIB installation on an ESXi host you must use esxcli commands using the following syntax:

 $esx=Get-EsxCli -VMHost <ESXi host on which use esxcli>  

esxcli commands can be executed from PowerCLI by exposing the esxcli functionalities. This is done using:

 $esx=Get-EsxCli -VMHost <ESXi host on which use esxcli>  

and later calling esxcli installation command:

 $"/tmp/$($FileVcloudAgent)", $false, $false, $true, $false, $false)  

On which each parameter has the following meaning:  
    install(string[] depot, boolean dryrun, boolean force,  
    boolean maintenancemode, boolean noliveinstall, boolean  
    nosigcheck, string proxy, string[] vibname, string[]  

That's all!!

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