Category: Server
Get system uptime
We all have our own ways of finding a servers / computers uptime.
But I thought I’d share my favorite way:
function Get-SrvUptime
{
$operatingSystem = Get-WmiObject Win32_OperatingSystem
[Management.ManagementDateTimeConverter]::ToDateTime($operatingSystem.LastBootUpTime)
}
HTTP 400 IIS Token Bloat
An old “friend” keeps keeps showing up in different environments. So since my old Blog is gone, I will add this again.
But this time I’ll just copy the info from Microsoft’s website.
Thank you Microsoft:Â https://support.microsoft.com/en-us/help/2020943/-http-400—bad-request-request-header-too-long-error-in-internet-info
HTTP 400 – Bad Request (Request Header too long)” error in Internet Information Services (IIS)
Symptoms
A domain user attempts to browse to a website hosted on Internet Information Services (IIS) 6.0 or higher by using Internet Explorer 6.0 or later. The website is configured to use Kerberos authentication. Instead of receiving the expected web page, the user is presented with an error message similar to the following:
HTTP 400 – Bad Request (Request header too long)
Cause
This issue may occur when the user is a member of many Active Directory user groups. When a user is a member of a large number of active directory groups the Kerberos authentication token for the user increases in size. The HTTP request that the user sends to the IIS server contains the Kerberos token in the WWW-Authenticate header, and the header size increases as the number of groups goes up. If the HTTP header or packet size increases past the limits configured in IIS, IIS may reject the request and send this error as the response.
Resolution
To work around this problem, choose one of the following options:
A) Decrease the number of Active Directory groups that the user is a member of.
OR
B) Modify the MaxFieldLength and the MaxRequestBytes registry settings on the IIS server so the user’s request headers are not considered too long. To determine the appropriate settings for the MaxFieldLength and the MaxRequestBytes registry entries, use the following calculations:
-
- Calculate the size of the user’s Kerberos token using the formula described in the following article:
New resolution for problems with Kerberos authentication when users belong to many groups
http://support.microsoft.com/kb/327825 - Configure the MaxFieldLength and the MaxRequestBytes registry keys on the IIS server with a value of 4/3 * T, where T is the user’s token size, in bytes.  HTTP encodes the Kerberos token using base64 encoding and therefore replaces every 3 bytes in the token with 4 base64 encoded bytes. Changes that are made to the registry will not take effect until you restart the HTTP service. Additionally, you may have to restart any related IIS services.
- Calculate the size of the user’s Kerberos token using the formula described in the following article:
NOTE: Depending on your application environment, you could also consider configuring the web site to use NTLM instead of Kerberos to work around this problem. Some application environments require Kerberos to be used for delegation purposes, and Kerberos is more secure than NTLM, so it is recommended that you do not disable Kerberos before considering the security and delegation ramifications of doing so.
More Information
By default, the MaxFieldLength registry entry is not present. This registry entry specifies the maximum size limit of each HTTP request header. The MaxRequestBytes registry entry specifies the upper limit for the total size of the Request line and the headers. Typically, this registry entry is configured together with the MaxRequestBytes registry entry. If the MaxRequestBytes value is lower than the MaxFieldLength value, the MaxFieldLength value is adjusted. In large Active Directory environments, users may experience logon failures if the values for both these entries are not set to a sufficiently high value.
For Internet Information Services (IIS) 6.0 and later, the MaxFieldLength and MaxRequestBytes registry keys are located at HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters. Configure them as shown in the following table:
| Name | Â Value Type | Â Value Data |
| Â MaxFieldLength | Â DWORD | Â (4/3 * T bytes) + 200 |
| Â MaxRequestBytes | Â DWORD | Â (4/3 * T bytes) + 200 |
Alternatively you may set the registry keys to their maximum values shown below. The Administrator should consider all potential security ramifications if he makes any changes to the registry settings:
| Name | Â Value Type | Value Data |
| Â MaxFieldLength | Â DWORD | Â 65534 |
| Â MaxRequestBytes | Â DWORD | Â 16777216 |
IMPORTANT: Changing these registry keys can be considered extremely dangerous. These keys allow larger HTTP packets to be sent to IIS, which in turn may cause Http.sys to use more memory and may increase vulnerability to malicious attacks.
NOTE: If MaxFieldLength is configured to its maximum value of 64KB, then the MaxTokenSize registry value should be set to 3/4 * 64 = 48KB. For more information on the MaxTokenSize setting, please see the Microsoft knowledge base article KB327825 listed below.
Azure Server Sizes and information regarding them
This information is collected from: Cynthia Nottingham​, and her ar​ticle: virtual-machines-windows-sizes​
​
​​​The standard sizes consist of several series: A, D, DS, F, Fs, G, and GS. Considerations for some of these sizes include:
- D-series VMs are designed to run applications that demand higher compute power and temporary disk performance. D-series VMs provide faster processors, a higher memory-to-core ratio, and a solid-state drive (SSD) for the temporary disk. For details, see the announcement on the Azure blog, New D-Series Virtual Machine Sizes.
- Dv2-series, a follow-on to the original D-series, features a more powerful CPU. The Dv2-series CPU is about 35% faster than the D-series CPU. It is based on the latest generation 2.4 GHz Intel Xeon® E5-2673 v3 (Haswell) processor, and with the Intel Turbo Boost Technology 2.0, can go up to 3.1 GHz. The Dv2-series has the same memory and disk configurations as the D-series.
- F-series is based on the 2.4 GHz Intel Xeon® E5-2673 v3 (Haswell) processor, which can achieve clock speeds as high as 3.1 GHz with the Intel Turbo Boost Technology 2.0. This is the same CPU performance as the Dv2-series of VMs. At a lower per-hour list price, the F-series is the best value in price-performance in the Azure portfolio based on the Azure Compute Unit (ACU) per core.
The F-series also introduces a new standard in VM size naming for Azure. For this series and VM sizes released in the future, the numeric value after the family name letter will match the number of CPU cores. Additional capabilities, such as optimized for premium storage, will be designated by letters following the numeric CPU core count. This naming format will be used for future VM sizes released but will not retroactively change the names of any existing VM sizes which have been released.
- G-series VMs offer the most memory and run on hosts that have Intel Xeon E5 V3 family processors.
- DS-series, DSv2-series, Fs-series and GS-series VMs can use Premium Storage, which provides high-performance, low-latency storage for I/O intensive workloads. These VMs use solid-state drives (SSDs) to host a virtual machine’s disks and also provide a local SSD disk cache. Premium Storage is available in certain regions. For details, see Premium Storage: High-performance storage for Azure virtual machine workloads.
- The A-series VMs can be deployed on a variety of hardware types and processors. The size is throttled, based upon the hardware, to offer consistent processor performance for the running instance, regardless of the hardware it is deployed on. To determine the physical hardware on which this size is deployed, query the virtual hardware from within the Virtual Machine.
- The A0 size is over-subscribed on the physical hardware. For this specific size only, other customer deployments may impact the performance of your running workload. The relative performance is outlined below as the expected baseline, subject to an approximate variability of 15 percent.
The size of the virtual machine affects the pricing. The size also affects the processing, memory, and storage capacity of the virtual machine. Storage costs are calculated separately based on used pages in the storage account. For details, see Virtual Machines Pricing Detailsand Azure Storage Pricing.
The following considerations might help you decide on a size:
- The A8-A11 sizes are also known as compute-intensive instances. The hardware that runs these sizes is designed and optimized for compute-intensive and network-intensive applications, including high-performance computing (HPC) cluster applications, modeling, and simulations. For detailed information and considerations about using these sizes, seeAbout the A8, A9, A10, and A11 compute intensive instances.
- Dv2-series, D-series, G-series, and the DS/GS counterparts are ideal for applications that demand faster CPUs, better local disk performance, or have higher memory demands. They offer a powerful combination for many enterprise-grade applications.
- The F-series VMs are an excellent choice for workloads that demand faster CPUs but do not need as much memory or local SSD per CPU core. Workloads such as analytics, gaming servers, web servers, and batch processing will benefit from the value of the F-series.
- Some of the physical hosts in Azure data centers may not support larger virtual machine sizes, such as A5 – A11. As a result, you may see the error message Failed to configure virtual machine or Failed to create virtual machine when resizing an existing virtual machine to a new size; creating a new virtual machine in a virtual network created before April 16, 2013; or adding a new virtual machine to an existing cloud service. See Error: “Failed to configure virtual machine” on the support forum for workarounds for each deployment scenario.​​
How can I see what OS version my Azure VM is running?
February 16, 2018
Azure, Powershell, Server, Tips and Trix, Virtual Machine, Windows
No Comments
vincent
I wanted to check what OS version I had deployed on a server in Azure, but I couldn’t remember if it was 2012 R2 or 2016.
I checked the server object in Azure and it gave me this
Hmmm…. that didn’t really answer my question (yes I could connect via RDP, but some times you can’t)
I know there are several scripts you can run to get information (that will need a connection, running scripts and so on, not everyone has this access, so they should be able to view this without scripts)
So I decided to check the disk connected to the server, and that gave me a better answer 🙂
There I can see it was a 2012 R2 DC based on the image 4.127….
So in the Resource group (or on VM) find the disk for the server, and you will see the Disk info in the Overview.
Enjoy