Technologist

Tech stuff about Cloud, DevOps, SysAdmin, Virtualization, SAN, Hardware, Scripting, Automation and Development

Browsing Posts tagged virtualization

One of the most important things you should do to your systems is to ensure they have the right time.
In this post I will show how to check and ensure your systems have the correct time using PowerCli.

==> Login to vCenter:

$admin = Get-Credential –Credential EXAMPLE\john
Connect-VIServer -Server vc.example.com -Credential $admin

==> Check time settings:

Output:

==> Set time to correct time:

==> Remove old NTP servers (if any):

Output:

==> Change NTP to desired configuration:

Output:

==> Enable Firewall Exception

==> Start NTPd service

==> Ensure NTPd service starts automatically (via policy)

==> Verify all is set the way you expected

Output:

Snapshots are a great feature, probably one of the coolest in virtualization. They can become a problem if they are not used appropriately, unfortunately sometimes we let them grow to an unmanageable size, which can bring performance issues and give us headaches when we need to delete them.

In this post, I will show you how to find out what snapshots are present in your environment, along with some other useful information, like size.

To run the commands below you will need to install PowerCLI (on windows), which is a way to manage a VMware environment programmatically using PowerShell scripting.

To get PowerCLI, go to: www.vmware.com/go/powercli

1) Once you have PowerCLI, open it up, a command prompt will appear:

// At this point you have a session open with your vCenter

2) Query your vCenter to find out what snapshots are present:

Let me explain what is going on:
Get-VM‘ asks for the VMs that are running on your vCenter, PowerCLI returns an object for each VM and you then asks for the snapshots of each returned VM object by using ‘Get-Snapshot‘, then you take that output and format it by using ‘Format-list‘, but you are only asking for the information about ‘vm,name,sizeGB,create,powerstate

You can request any of the following:
Description
Created
Quiesced
PowerState
VM
VMId
Parent
ParentSnapshotId
ParentSnapshot
Children
SizeMB
SizeGB
IsCurrent
IsReplaySupported
ExtensionData
Id
Name
Uid

3) The above will give you the info you want, but I prefer CSV reports that I can share with the team or management. To get a good CSV report run the following:

I recommend taking a look at VMware’s best practices around snapshots:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1025279