Tag Archives: vmware

VCAP6.5-DCV Design – Objective 2.2 Map service dependencies

This blog post covers objective 2.2 (Map service dependencies) of the VCAP6.5-DCV Design exam. It is based on the VMware Certified Advanced Professional 6.5 in Data Center Virtualization Design (3V0-624) Exam Preparation Guide (last update August 2017).

The necessary skills and abilities are documented in the exam prep guide for the older VCAP6-DCV Design exam (3V0-622). I think they also apply to the current version of the exam:

  • Evaluate dependencies for infrastructure and application services that will be included in a vSphere design
  • Create Entity Relationship Diagrams that map service relationships and dependencies
  • Analyze interfaces to be used with new and existing business processes
  • Determine service dependencies for logical components
  • Include service dependencies in a vSphere 6.x Logical Design
  • Analyze services to identify upstream and downstream service dependencies
  • Navigate logical components and their interdependencies and make decisions based upon all service relationships

Let’s start with the first topic of this objective.

Evaluate dependencies for infrastructure and application services that will be included in a vSphere design

This topic covers two different parts of our vSphere design:

  • infrastructure, and
  • application services

You should clarify what components of your design depend on each other, or if they depend on components, that are not part of your design. VMware HA needs a shared Storage, or VMware ESXi needs NTP and DNS to work properly.

The same applies to the application services (or applications) that are part of your design. What dependencies do they have. Imagine a three-tier application with database, application logic and web frontend.

You must be able to identify and describe these dependencies.

Create Entity Relationship Diagrams that map service relationships and dependencies

If you are able to identify and describe the dependencies, you also must be able to create a Entity Relationship Diagrams (ER-Diagram) to visualize these dependencies.

Do your homework and try to identify these dependencies at the beginning. Tools like the vRealize Infrastructure Navigator can help you to identify them.

Analyze interfaces to be used with new and existing business processes

It is pretty important to understand how systems interact. To gain this knowledge, you have to analyze the interfaces of business processes. This doesn’t mean that you have to click through ERP applications, but you should get familiar with how processes are tight together.

Determine service dependencies for logical components

You also have to identify the service dependencies for the logical components in your design. You can use tools like vRealize Operations Manager or the Infrastructure Navigator to get the necessary information.

Include service dependencies in a vSphere 6.x Logical Design

The identified service dependencies have to be included into the logical design. This is a pretty important step and you should pay it the necessary attention. Tables and ER diagrams will help you at this step.

Analyze services to identify upstream and downstream service dependencies

An upstream service is a service, which is mandatory for another service, because it relies on it. Downstream services need upstream services to work properly. For example: DNS is an upstream service for Active Directory.

The understanding of up- and downstream services is important for things like startup/ shutdown plans.

Navigate logical components and their interdependencies and make decisions based upon all service relationships

You should visualize the service dependencies. This will help you to evaluate the impact if a service fails or how service are interact with each other.

Summary

Most of the topics in this objective overlap. Quite basic everything is about the understanding how things are connected and interact. This will help you to get a better understanding of dependencies and what services are crucial for the business or your solution.

Think again on DNS. No one of us will ever build a solution with a single DNS server, because nearly everything will melt down if DNS is not available. DNS is a perfect example for an upstream service.

vCenter Migration from 6.0 to 6.7 fails due to missing user role

Actually, yesterday should be the day at which I migrate one of the last physical Windows vCenter servers installed in my customer base. Actually… the migration failed twice. And each time I had to rollback, power-on the old physical server, reset the computer account etc.

The update was from VMware vCenter Server 6.0 Update 3d (7462484) on a Windows 2012 R2 server to vCenter Server 6.7 Update 3 (Appliance). The migration failed at 62% with the following message:

I found the same error in the content-library-firstboot.py_9150_stderr.log file of the downloaded log bundle.

Okay, that’s a pretty long error message and I had no idea where I should start searching. But it seems related to the Content Library of the vCenter. And it looks like it is related to the privileges.

A forum post led me to the content library administrator role. The author had to deal with a failed migration (6.5 to 6.7), but his conten administrator role was missing. In my case, the role was existent.

Sorry for the german translation. As you can see, the role was existent… Obviously. I tried to add a new role with the name com.vmware.Content.Admin, as mentioned in the forum post, and… a new role appeared.

You might notice the “Beispiel” or “Example”. That’s the difference. Whatever the other role is or what its look like, it is definitely not the original content library administrator role.

And to make a long story short: The migration was successful after this small change.

VCAP6.5-DCV Design – Objective 2.1 Map business requirements to a vSphere 6.x logical design

The last few weeks have been quite busy. Time to focus on exam preparation again. Let’s start with the first objective of the second section.

This blog post covers objective 2.1 (Map business requirements to a vSphere 6.x logical design) of the VCAP6.5-DCV Design exam. It is based on the VMware Certified Advanced Professional 6.5 in Data Center Virtualization Design (3V0-624) Exam Preparation Guide (last update August 2017).

The necessary skills and abilities are documented in the exam prep guide for the older VCAP6-DCV Design exam (3V0-622). I think they also apply to the current version of the exam:

  • Analyze requirements for functional and non-functional elements
  • Build non-functional requirements into a specific logical design
  • Translate stated business requirements into a logical design
  • Incorporate the current state of a customer environment into a logical design

Let’s start with

Analyze requirements for functional and non-functional elements

Functional and non-functional elements sounds familiar. I wrote about functional and non-functional requirements in the previous objective 1.3 (Determine risks, requirements, constraints, and assumptions). When we talk about requirements, we have to differ between functional (WHAT) and non-functional (HOW) requirements. Some examples:

  • Solution must comply with ISO standards
  • The uptime must be at a minimum of 99,9%
  • Users must be able deploy new virtual machine within 15 minutes after approval

This step is about analyzing the requirements and check if it is a functional or a non-functional element. Check this examples:

Requirementfunctional/ non-functional
Solution must comply with ISO standardsfunctional
The uptime must be at a minumum of 99,9% functional
Existing contracts must be used for purchasing server hardwarenon-functional
PowerShell has to be used for automation tasks non-functional

Remember: We have to differ between WHAT (functional) and HOW (non-functional).

Build non-functional requirements into a specific logical design

A logical design is more detailed compared to the conceptual design. A conceptual design is an abstract or high level design. The logical design contains more information, is more low-level than a conceptual design. The purpose of a logical design is refine the conceptual design and add more details and information.

With the determined and categorized requirements we can start to add more details to our design, for example we can define, that server hardware will be purchased from DELL or HPE. Or that we don’t need traditional, dedicated shared storage, because the solution must be hyper-converged.

Pretty important: A requirement is a requirement, regardless how dumb it is. This is pretty important for the exam – and your job. ;)

Translate stated business requirements into a logical design

This is pretty similar to the written above. You have to take the business requirements into account. Similar to the section above, business requirements can also be categorized into functional or non-functional elements.

Incorporate the current state of a customer environment into a logical design

If your customer is not asking for a greenfield deployment, you have to take the current environment of the customer into account. The solution must fit into the current environment. Of course, this results in further requirements that have to be fulfilled.

Summary

The main aspect of this objective is to review all requirements, determine if they are functional or non-functional, and use them to create a logical design. A logical design does not contain IP addresses or VLANs. But it contains all major components and their relationships, like data flows and connections.

Links

VCAP6.5-DCV Design – Objective 1.3 Determine risks, requirements, constraints, and assumptions

This blog post covers objective 1.3 (Determine risks, requirements, constraints, and assumptions) of the VCAP6.5-DCV Design exam. It is based on the VMware Certified Advanced Professional 6.5 in Data Center Virtualization Design (3V0-624) Exam Preparation Guide (last update August 2017).

The first objective of the exam prep guide has covered the business requirements. Now we have to do similar for the affected applications.

The necessary skills and abilities are documented in the exam prep guide for the older VCAP6-DCV Design exam (3V0-622). I think they also apply to the current version of the exam:

  • Differentiate between the concepts of risks, requirements, constraints, and assumptions
  • Given a statement, determine whether it is a risk, requirement, constraint, or an assumption
  • Analyze impact of VMware best practices to identified risks, constraints, and assumptions

Differentiate between the concepts of risks, requirements, constraints, and assumptions

I wrote a couple of times about risks, requirements, constraints and assumptions, but I missed to explain the meaning of each of these terms. I will use the following order:

  • requirements
  • risks
  • constraints
  • assumptions

So let us start with “What is a requirement“? A requirement is something that a has to be achieved. This can be applied to business or technical things. Without defined requirements, you would have no clue what your design should cover. If you define a requirement, you should test it with the following question: Is the defined requirement

  • specific
  • feasable
  • verifiable
  • traceable
  • unambiguous

When we talk about requirements, we have to differ between functional (WHAT) and non-functional (HOW) requirements. Some examples:

  • Solution must comply with ISO standards
  • The uptime must be at a minumum of 99,9%
  • Users must be able deploy new virtual machine within 15 minutes after approval

A Risks is a potential event, that might prevent us from achieving the defined project goals, or which can cause that the project completely fails. They are often common points in every projekct. The best we can do is to identify and list every risk that might prevent us from successfully finish the project. Some examples:

  • Missing the delivery date
  • Vendor discontinued parts of the solution
  • Hidden incompatibility with currently used frameworks

Constraints can be a limiting factor when we design our solution. They can be understood as cornerstones that set the borders of our solution. Contraints are always very specific. Examples:

  • The costs per user must not exceed 5 €
  • The project has to be finished withing 9 months
  • The solution must include servers from HPE

In opposite to constraints, which are very specific, assumptions are considered to be true without proof in the planning phase. This is pretty important! We are talking about the time, when we put our design together. Examples:

  • Rackspace will be available when the HW needs to be deployed
  • A MS SQL database server will be available at the installation date
  • A specific decision is made when needed

Summary

As I wrote at the beginning of this article: It is important to understand these terms. In simple words:

  • requirements: Things that have to met to successfully finish the project
  • risks: Things that might happen and that put our project at risk
  • constraints: Limiting factors to our project design
  • assumptions: Things that are considered to be true, but that are not proofed during the planning phase

That is a pretty simple summary, but it should be good enough to be memorized. :)

Links

VCAP6.5-DCV Design – Objective 1.2 Gather and analyze application requirements

This blog post covers objective 1.2 (Gather and analyze application requirements) of the VCAP6.5-DCV Design exam. It is based on the VMware Certified Advanced Professional 6.5 in Data Center Virtualization Design (3V0-624) Exam Preparation Guide (last update August 2017).

The first objective of the exam prep guide has covered the business requirements. Now we have to do similar for the affected applications.

The necessary skills and abilities are documented in the exam prep guide for the older VCAP6-DCV Design exam (3V0-622). I think they also apply to the current version of the exam:

  • Gather and analyze application requirements for a given scenario
  • Determine the requirements for a set of applications that will be included in the design
  • Collect information needed in order to identify application dependencies
  • Given one or more application requirements, determine the impact of the requirements on the design

Gather and analyze application requirements for a given scenario

As a result of our already done work, we should know with what applications we have to deal in our project. Now ee have to gather the requirements of those applications. The necessary techniques are already known to us:

  • interviews with the relevant stakeholders and/ or developers or engineers
  • existing documentation about the deployment
  • our documented baseline from objective 1.1
  • vendor documentation/ support/ knowledge base articles

It is pretty important to understand what requirements these applications have. It depends on the workload and the applications itself. Tools like perfmon or capacity planning tools can help us to get a solid knowledge about the current and planned capacity/ performance requirements.

But we should not only focus on performance. There is much more to take into account, to be more specific: AMPRS

It stands for

  • Availability
  • Manageability
  • Performance
  • Recoverability, and
  • Security

You can read an detailed explanation here.

Determine the requirements for a set of applications that will be included in the design

This is similar to the written above. When we talk about a set of applications, we have to take the dependencies between these applications into account.

Collect information needed in order to identify application dependencies

To gain the necessary information, we have to talk to the right people, which means that we have to talk to developers, engineers and/ or end-users. We have to deep dive into existing customer and/ or vendor documentation. And we need to use the right tools to map the found dependencies. This can be done with Microsoft Visio, OmniGraffle or similar.

Given one or more application requirements, determine the impact of the requirements on the design

With the knowledge about the applications and the dependencies between them, it is time to make some design decisions. These decisions must support the documented requirements, especially when we think about the requirements in regard of availability, manageability, performance, recoverability, and security.

The key is to understand the impact of the made decisions for the rest of the design.

Summary

I will try to summarize this objective. The last blog post has covered the business requirements and the process from gathering the required information, over the documentation, until the point at which we can start creating a design. This blog post covers the same, but not for the business requirements, but for the applications and the requirements of these applications.

We can gather the necessary information by talking to the relevant stakeholders, engineers, developers etc. Customer and/ or vendor documentation and other sources can be used to get a better understanding of the different application requirements. We also need to understand the dependencies between the different applications, especially if only a subset of applications is virtualized. Our work is supported by different tools, especially for performance analysis, capacity planning and documentation.

With the gathered information we will able to make design decisions that fulfill the requirements (Think about AMPRS).

Links

VCAP6.5-DCV Design – Objective 1.1 Gather and analyze business requirements

This blog post covers objective 1.1 (Gather and analyze business requirements) of the VCAP6.5-DCV Design exam. It is based on the VMware Certified Advanced Professional 6.5 in Data Center Virtualization Design (3V0-624) Exam Preparation Guide (last update August 2017).

When you get the task to design something , you will instinctively start gathering information about the requirements that have to be fulfilled. Everything IT is doing should support the business in some way.

The necessary skills and abilities are documented in the exam prep guide for the older VCAP6-DCV Design exam (3V0-622). I think they also apply to the current version of the exam:

  • Associate a stakeholder with the information that needs to be collected
  • Utilize inventory and assessment data from a current environment to define a baseline state
  • Analyze customer interview data to explicitly define customer objectives for a conceptual design
  • Determine customer priorities for defined objectives
  • Ensure that Availability, Manageability, Performance, Recoverability and Security (AMPRS) considerations are applied during the requirements gathering process
  • Given results of the requirements gathering process, identify requirements for a conceptual design
  • Categorize requirements by infrastructure qualities to prepare for logical design requirements

Associate a stakeholder with the information that needs to be collected

Let’s start with the stakeholders and why they are important for us. But what is a stakeholder? A stakeholder is a person with an interest or concern in something, especially a business (Oxford). Stakeholders can be internal or external parties. An internal stakeholder is someone with a direct relationship to the company. An external stakeholder has no direct connection to the company, but it is affected in some way. This can be suppliers, the government, or other groups. A stakeholder can be anyone, but in our context stakeholders are typically

  • C-Level Executives (CEO, CFO, CIO etc.)
  • Vice Presidents
  • Managers, but also
  • Engineers and end users

As always: It depends. :)

Utilize inventory and assessment data from a current environment to define a baseline state

We also need to understand the current environment and what is currently deployed at the company. Interviews with the stakeholders are important, but in most cases they will not answer all questions. Depending on what is currently deployed, different tools can be used to gain the necessary data. Some examples:

  • RVTools, PowerCLI, vSphere Web Client, vROps etc
  • Custom scripts
  • Windows Server Manager
  • Network Monitoring Tools, like HPE Intelligent Management Center
  • Asset Management

It is important to document the results of the assessment. This is the baseline state of the current environment.

Analyze customer interview data to explicitly define customer objectives for a conceptual design

Now we need to get back to the results of the interviews that we did with the stakeholders to define the goals and the scope of the design. We also need to understant the the

  • Constraints
  • Assumptions,
  • Requirements, and
  • Risks

When we talk about requirements, we have to differ between functional (WHAT) and non-functional (HOW) requirements.

These information will allow us to create a conceptual design, which is written down in a workbook document.

Determine customer priorities for defined objectives

The next step is to define the priorities over the defined objectives. It is important to weight e.g. requirements and risks. Milestones have to be defined. They will help us to measure the success of the project and keep it on track.

Ensure that AMPRS considerations are applied during the requirements gathering process

AMPRS stands for

  • Availability
  • Manageability
  • Performance
  • Recoverability, and
  • Security

It is important to understand the meaning of each of these terms.

Availability considerations address the availability requirements of our design. These are typically expressed by percent uptime of a specific system. For example: 99,5% availability for file services.

Manageability considerations address the management and operational requirements of our design. This can be alerting, reports, access concepts etc.

Performance considerations express the required performance characteristics of the design. For example: Mails per second by a given size.

Recoverability considerations cover the ability to recover from an unexpected incident or disaster. This topic typically addresses backup and recovery of our design.

Security considerations cover the requirements around data control, access management, governance, risk management etc.

Given results of the requirements gathering process, identify requirements for a conceptual design

Now we have collected information from the relevant stakeholders, including the goals, scope, and CARR (constraints, assumptions, requirements, risks), and we have collected details about the current environment. Now it is time to put these information together and create a conceptual design.

The conceptual design must be approved by the stakeholders. This assures that everything is covered. Creating a conceptual design is an iterative process. The conceptual design is finished when the relevant stakeholders have approved it.

Categorize requirements by infrastructure qualities to prepare for logical design requirements

Sounds simple, but it can be challenging: The documented requirements have to be grouped by infrastructure categories, eg.

  • Networking
  • Storage
  • Recovery
  • Compute
  • VM
  • Security

Based on the CARR and the AMPRS considerations, we made design decisions. These decisions affect each of the infrastructure categories. At this point, we can review each of our decisions and mapping the requirements to the infrastructure will ease the creation of a high-level logical design.

Summary

Let me try to simplify this complex process a bit.

We were asked to solve a problem for a company. To solve this problem, we have to design a solution. To create this design, we have to identify the relevant stakeholders. These stakeholders will help us to gather information about the goals, the scope, about constraints, assumptions, requirements and risks. Especially when it comes to the requirements, we have to take availability, manageability, performance, recoverability and security considerations into account.

We can use different tools to collect information about the current environment.

At this point we know WHAT the company want, and we know WHAT they are currently running.

Now we can start with the creation of a conceptual design, which has to be approved by the relevant stakeholders.

To prepare the logical design, we need to map the documented requirements to the different categories of the infrastructure.

Links

VMware Certified Advanced Professional — Data Center Virtualization Design 2019 Study Guide

Last year in September I’ve passed the VCAP6-DCV Deployment exam. After a busy first half of 2019 it’s time to start preparing the VMware Certified Advanced Professional — Data Center Virtualization Design 2019 exam.

There are many great study guides out there, but in most cases I need “my own study guide” to feel well prepared. I hope the step to publish my notes helps me to stay focused and motivated.

Image by Pexels from Pixabay

In opposite to the Deploy exam, the Design exam is a MC exam. 135 Minutes for 60 questions. Sounds easy, but it’s told that it’s one of the hardest exams available by VMware.

The exam is split into three sections:

  • Section 1 – Create a vSphere 6.5 Conceptual Design
  • Section 2 – Create a vSphere 6.x Logical Design from an Existing Conceptual Design
  • Section 3 – Create a vSphere 6.x Physical Design from an Existing Logical Design

Each section contains several objects.

  • Objective 3.1 – Transition from a logical design to a vSphere 6.x physical design
  • Objective 3.2 – Create a vSphere 6.x physical network design from an existing logical design
  • Objective 3.3 – Create a vSphere 6.x physical storage design from an existing logical design
  • Objective 3.4 – Determine appropriate computer resources for a vSphere 6.x physical design
  • Objective 3.5 – Determine virtual machine configuration for a vSphere 6.x physical design
  • Objective 3.6 – Determine data center management options for a vSphere 6.x physical design

I will try to cover each objective in a blog post and add a link here. Feel free to add comments, corrections and questions. :)

Out of space – first steps when a datastore runs out of space

This is a situation that never should happen, and I had to deal with it only a couple of times in more than 10y working with VMware vSphere/ ESXi. In most cases, the reason for this was the usage of thin-provisioned disks together with small datastores. Yes, that’s a bad design. Yes, this should never happen.

There is a nearly 100% chance that this setup will fail one day. Either because someone dumps much data into the VMs, or because of VM snapshots. But such a setip WILL FAIL one day.

Yesterday was one of these days and five VMs have stopped working on a small ESXi in a site of one of my customers. A quick look into the vCenter confirmed my first assumption. The datastore was full. My second thought: Why are there so many VMs on that small ESXi host, and why they are thin-provisioned?

The vCenter showed me the following message on each VM:

There is no more space for virtual disk $VMNAME.vmdk. You might be able to continue this session by freeing disk space on the relevant volume, and clicking Retry. Click Cancel to terminate this session.

Okay, what to do? First things first:

  1. Is there any unallocated space left on the RAID group? If yes, expand the VMFS.
  2. Are there any VM snapshots left? If yes, remove them
  3. Configure 100% memory reservation for the VMs. This removes the VM memory swap files and releases a decent amout of disk space
  4. Remove ISO files from the datastore
  5. Remove VMs (if you have a backup and they are not necessary for the business)

This should allow you to continue the operation of the VMs. To solve the problem permanently:

  1. Add disks to the server and expand the VMFS, or create a new datastore
  2. Add a NFS datastore
  3. Remove unnecessary VMs
  4. Setup a working monitoring , setup alarms, do not overprovision datastores, or switch to eager-zeroed disks

Such an issues should not happen. It is not rude to say here: This is simply due to bad design and lack of operational processes.

User vdcs does not have the expected uid 1006

Sorry for the long delay since my last blog post – busy times, but with lots of vSphere. :) Today, I did an upgrade of a standalone vCenter Server Appliance at one of my healthcare customers. The vCenter was on 6.0 U3 and I had to upgrade it to 6.7 U2. It was only a small deployment with three hosts, so nothing fancy. And as with in many other vSphere upgrades, I came across this warning message:

Warning User vdcs does not have the expected uid 1006
Resolution Please refer to the corresponding KB article.

I saw this message multiple times, but in the past, there was no KB article about this, only a VMTN thread. And this thread mentioned, that you can safely ignore this message, if you don’t use a Content Library. Confirmation enough to proceed with the upgrade. :)

Meanwhile, there is a KB article:

Uploading content to the library fails with error: Content Library Service does not have write permission on this storage backing (52559)

This is a statement from the KB article:

Note: You can safely ignore this message if you are not using Content Library Service before the upgrade, or using it only for libraries not backed by NFS storage.

Currently, I don’t have cusomters with NFS backed Content Libraries, but if you do, you might want to take a look at it. Especially if you have done an upgrade from 6.0 to 6.5 or 6.7 and you want to start using Content Libraries now.

Poor performance with Windows 10/ 2019 1809 on VMFS 6

TL;DR: This bug is still up to date and has not been fixed yet! Some user in the VMTN thread mentioned a hotpatch from VMware, which seems to be pulled. A fix for this issue will be available with ESXi 6.5 U3 and 6.7 U3. The only workaround is to place VMs on VMFS 5 datastores, or avoid the use of snapshots if you have to use VMFS 6. I can confirm, that Windows 1903 is also affected.

One of my customers told me that they have massive performance problems with a Horizon View deployment at one of their customers. We talked about this issue and they mentioned, that this was related to Windows 10 1809 and VMFS 6. A short investigation showed, that this issue was well known, and even VMware is working on this. In their case, another IT company installed the Cisco HyperFlex solution and the engineer was unaware of this issue.

Image by Manfred Antranias Zimmer from Pixabay

What do we know so far? In October 2018 (!), shortly after the release of Windows 10 1809, a thread came up in the VMTN (windows 10 1809 slow). According to the posted test results, the issue occurs under the following conditions.

  • Windows 10 1809
  • VMware ESXi 6.5 or 6.7 (regardless from build level)
  • VM has at least one snapshot
  • VM is placed on a VMFS 6 datastore
  • Space reclamation is enabled or disabled

The “official” statement of the VMware support is:

The issue is identified to be due to some guest OS behavior change in this version of windows 10, 1809 w.r.t thin provisioned disks and snapshots, this has been confirmed as a bug and will be fixed in the following releases – 6.5 U3 and 6.7U3, which will be released within End of this year (2019).

https://communities.vmware.com/message/2848206#2848206

I don’t care if the root cause is VMFS 6 or Windows 10. But VMware and Microsoft needs to get this fixed fast! Just to make this clear: You will face the same issues, regardless if you run Windows 10 in a VM, use Windows 10 with Horizon View, or Windows 10 with Citrix. When VMFS 6 and Snapshots comes into play, you will ran into this performance issue.

I will update this blog post when I get some news.