Monthly Archives: January 2015

VCAP DCD Study – Home Lab Design Part 4

Objective 2.5 – Build Performance Requirements into the Logical Design

1. Understand what logical performance services are provided by VMware solutions.


  • Transparent Page Sharing – Shares identical memory pages across multiple VMs. This is enabled by default. Consideration should be given to try and place similar workloads on the same hosts to gain maximum benefit.
  • Memory Ballooning – Controls a balloon driver which is running inside each VM. When the physical host runs out of memory it instructs the driver to inflate by allocating inactive physical pages. The ESXi host can uses these pages to fulfill the demand from other VMs.
  • Memory Compression – Prior to swapping, memory pages out to physical disks. The ESXi server starts to compress pages. Compared to swapping, compression can improve the overall performance in an memory over commitment scenario.
  • Swapping – As the last resort, ESXi will start to swap pages out to physical disk
  • Caching – Allows the use of SSD drives to act as a Cache quicker than using spinning disks


  • vStorage APIs for Array Integration (VAAI) –  is a feature introduced in ESXi/ESX 4.1 that provides hardware acceleration functionality. It enables your host to offload specific virtual machine and storage management operations to compliant storage hardware. With the storage hardware assistance, your host performs these operations faster and consumes less CPU, memory, and storage fabric bandwidth.
  • Storage I/O Control (SIOC) – was introduced in vSphere 4.1 and allows for cluster wide control of disk resources. The primary aim is to prevent a single VM on a single ESX host from hogging all the I/O bandwidth to a shared datastore. An example could be a low priority VM which runs a data mining type application impacting the performance of other more important business VMs sharing the same datastore.
  • vSphere Storage API’s – Storage Awareness (VASA) – VASA is a set of APIs that permits storage arrays to integrate with vCenter for management functionality


  • Network IO Control (NIOC) – When network I/O control is enabled, distributed switch traffic is divided into the following predefined network resource pools: Fault Tolerance traffic, iSCSI traffic, vMotion traffic, management traffic, vSphere Replication (VR) traffic, NFS traffic, and virtual machine traffic.  You can control the bandwidth each network resource pool is given by setting the physical adapter shares and host limit for each network resource pool.

2. Identify and differentiate infrastructure qualities (Availability, Manageability, Performance, Recoverability, Security)

See Objective 2.3

3. List the key performance indicators for resource utilization.

Performance KPI’s will be Processor, Memory, Disk, and Network.

Skills and Abilities
4. Analyze current performance, identify and address gaps when building the logical design.

This should be done during the current state analysis using well documented tools such as capacity planner as well as OS tools such as perfmon and top.

5. Using a conceptual design, create a logical design that meets performance requirements.

I don’t need to use any tiered storage or resource pools in my design,  this objective is asking us to create a logical diagram to depict the performance requirements, so for example if the database needed a high amount of IOPS and the Dev servers need  lower IOPS then I would draw up a logical diagram to show the different tiers of storage and group VMs on the relevant tiers.

6. Identify performance-related functional requirements based on given non-functional requirements and service dependencies.

The non-functional requirement is I can only spend £300 on storage, this will limit my choices, so depending on what type (SSD(ha ha!) or SATA)  and how many disks I buy, I will be limited to a certain amount of IOPS.


7. Define capacity management practices and create a capacity plan.

Ability to utilize resources efficiently without compromising performance
Uitlizing tools to forecast resource capacity (being proactive instead of reactive)

8. Incorporate scalability requirements into the logical design.

Overprovision enough for future growth, I’ve over provisioned for my initial requirements.

9. Determine performance component of SLAs and service level management processes.

Business Capacity Mgmt

  • ensure future business requirements are understood & have sufficient capacity to meet the requirements

Service Capacity Mgmt

  • resource consumption, activity patterns/peaks/troughs of live operational services

Component Capacity Mgmt

  • performance & capacity of underlying IT service components (CPU, RAM, Disks, etc..)


Objective 2.6 – Build Recoverability Requirements into the Logical Design

1.Understand what recoverability services are provided by VMware solutions.

APIs needed for 3rd party solutions

2.Identify and differentiate infrastructure qualities (Availability, Manageability, Performance, Recoverability, Security)

See Objective 2.3

3.Differentiate Business Continuity and Disaster Recovery concepts.

Business continuity is a proactive action focused on avoiding or mitigating the impacts of risks before they happen.

Below points borrowed from the Brownbag VCAP DCD Study notes.

  • The business must continue to operate for weeks, months and years
  • Who, What, Where and When is needed
  • Not just technical, whole of business
  • Very Strategic

Disaster recovery is focused on how to return services after an outage or failure has occurred which is a reactive action.

  • We hoped it would never happen but it has
  • Get the business running again ASAP
  • Tactical, Technical

4. Describe and differentiate between RTO and RPO

RTO – recovery time objective; appropriate time allowed to recover a critical system.

RPO recovery point objective; appropriate recovery point of a system, determining what is ‘acceptable’ data loss.

Skills and Abilities

5.Given specific RTO and RPO requirements, build these requirements into the logical design.

Taking into account the RTO and RPO requirements what options do we have to implement a DR solution? Array based or vSphere replication? Is there network bandwidth for replication is there budget? etc etc…

6. Given recoverability requirements, identify the services that will be impacted and provide a recovery plan for impacted services.

Basically come up with a good DR plan with a detailed run book.

7.Given specific regulatory compliance requirements, build these requirements into the logical design.

Backups & retention periods can be defined by regulation.

8.Based on customer requirements, identify applicable site failure / site recovery use cases.

How will the DR site be configured? Will we use a cloud based DR? Maybe use the failover site as a dual purpose site e.g. have pre-prod workloads running in there as well as DR.

9.Determine recoverability component of SLAs and service level management processes.

Taken from the pdf on the blueprint – Practical Guide to Business Continuity and Disaster Recovery with VMware Infrastructure

In a real-world scenario, there would be an interaction with the business owners to establish SLAs and these would drive design considerations. The implementation outlined in this VMbook was designed to apply generically to as many cases as possible and was based in part on interviews with senior architects within the VMware customer base to determine a “level set” in terms of needs,requirements, and so on. Typical questions asked of these architects include the following:

What type of SLAs do you have with the business?
Recovery Point Objectives
Recovery Time Objectives

BCDR plans have traditionally been documented as runbooks – i.e., what to do if disaster strikes. Increasingly, this runbook is being automated to make the process more predictable and less prone to error. The ability to test this plan is also a key consideration.

10. Based on customer requirements, create a data retention policy.

Retention Policy – Data Recovery backups are preserved for a variable period of time. You can choose to keep more or fewer backups for a longer or shorter period of time. Keeping more backups consumes more disk space, but also provides more points in time to which you can restore virtual machines. As backups age, some are automatically deleted to make room for new backups. You can use a predefined retention policy or create a custom policy.


Objective 2.7 – Build Security Requirements into the Logical Design

1. Understand what security services are provided by VMware solutions.

  • VMware compliance checkers
  • vShield
  • Hardening guides for the relevant ESXi version

2. Identify and differentiate infrastructure qualities (Availability, Manageability, Performance, Recoverability, Security).

Covered in objective 2.3 ( I see a pattern here!)

3. Describe layered security considerations, including but not limited to Trust Zones.

Trust zones such as a DMZ, Departmental , PCI compliance, or application (3 tier app), there are three trust zone configurations: Partially Separated Physical; Partially Separated Virtual; Fully collapsed.

Can be implemented using VLANs, Firewalls, Anit-Virus, end point appliances, IDS.

Skills and Abilities

4. Identify required roles, create a role-based access model and map roles to services.

Use active directory for all access with the exception of a local admin group in case of active directory failure.

  • Where possible, grant permissions to groups rather than individual users.
  • Grant permissions only where needed. Using the minimum number of permissions makes it easier to understand and manage your permissions structure.
  • If you assign a restrictive role to a group, check that the group does not contain the Administrator user or other users with administrative privileges. Otherwise, you could unintentionally restrict administrators’ privileges in parts of the inventory hierarchy where you have assigned that group the restrictive role.
  • Use folders to group objects to correspond to the differing permissions you want to grant for them.
  • Use caution when granting a permission at the root vCenter Server level. Users with permissions at the root level have access to global data on vCenter Server, such as roles, custom attributes, vCenter Server settings, and licenses. Changes to licenses and roles propagate to all vCenter Server systems in a Linked Mode group, even if the user does not have permissions on all of the vCenter Server systems in the group.

5. Create a security policy based on existing security requirements and IT governance practices.

This is talking about security compliance policies, change policies, patching policies, configuration policies and access control.

6. Incorporate customer risk tolerance into the security policy.

I guess depending on the industry the risk tolerance can vary, for example a travel agency’s IT security policy would not be as stringent as say a company providing IT services for the military.

7. Given security requirements, assess the services that will be impacted and create an access management plan.

Not entirely sure what this is asking or referring to but assuming it’s talking about external access to secure services, will do some more digging on this one, update to follow.

8. Given a regulatory requirement example, determine the proper security solution that would comply with it.

e.g. PCI compliance or IL3 compliance, ensuring the design caters for the specific requirements and everything will come back clean if there was an audit.

9. Based upon a specified security requirement, analyze the current state for areas of compliance/non-compliance.

referring to VMware vCenter Configuration Manager which has compliance checker integrated in to the product.

10. Explain how compliance requirements will impact the logical security design

Compliance could involve purchasing specific software to meet the requirements such as vShield endpoint of Juniper virtual gateway, also extra firewalls, switches etc if physical segregation is essential.

VCAP DCD Study – Home Lab Design Part 3

Objective 2.3 – Build Availability Requirements into the Logical Design

1. Understand what logical availability services are provided by VMware solutions.

I’ll be utilising VMware HA and possibly Fault Tolerance in the design.

2. Identify and differentiate infrastructure qualities (Availability, Manageability, Performance, Recoverability, Security)

  • Availability is the ability of a system or service to perform its required function when required. It is usually calculated as a percentage like 99,9%.
  • Manageability describes the expense of running the system. If you have a huge platform that is managed by a tiny team the operational costs are very low.
  • Performance is the measure of what is delivered by a system. This accomplishment is usually measured against known standards of speed completeness and speed.
  • Recoverability describes the ability to return a system or service to a working state. This is usually required after a system failure and repair.
  • Security is the process of ensuring that services are used in an appropriate way.

3. Describe the concept of redundancy and the risks associated with single points of failure.

There will be some redundancy built in to my design but not at the level the exam blueprint requires, for the purpose of study below is some info from the link provided in the blue print.

Design Principles for High Availability

The key to architecting a highly available computing environment is to eliminate single points of failure. With the potential of occurring anywhere in the environment, failures can affect both hardware and software. Building redundancy at vulnerable points helps reduce or eliminate downtime caused by [implied] hardware failures. These include redundancies at the following layers:

  • Server components such as network adaptors and host bus adaptors (HBAs)
  • Servers, including blades and blade chassis
  • Networking components
  • Storage arrays and storage networking

4. Differentiate Business Continuity and Disaster Recovery concepts.

Business continuity is a proactive action focused on avoiding or mitigating the impacts of risks before they happen.

  • The business must continue to operate for weeks, months and years
  • Who, What, Where and When is needed
  • Not just technical, whole of business
  • Very Strategic

Disaster recovery is focused on how to return services after an outage or failure has occurred which is a reactive action.

  • We hoped it would never happen but it has
  • Get the business running again ASAP
  • Tactical, Technical

Skills and Abilities

5. Determine availability component of service level agreements (SLAs) and service leve management processes.

Define an SLA for each and design a setup that will accommodate. For example if your SLA for a certain VM failure is 0, then configure that VM for FT. Or if your SLA is a couple minutes then VMware HA should be good enough. If there are other services that you commit to (i.e. performance) then create storage tiers as necessary

6. Explain availability solutions for a logical design based on customer requirements.

As mentioned I won’t be designing  a DR solution, but below is an example of a logical design of an availability solution using SRM.

dr diag

7. Define an availability plan, including maintenance processes.

This was taken from the link provided in the blue print.

VMware vSphere makes it possible to reduce both planned and unplanned downtime without the cost and complexity of alternative solutions. Organizations using VMware can slash planned downtime by eliminating most scheduled downtime for hardware maintenance. VMware VMotion™ technology, VMware Distributed Resource Scheduler (DRS) maintenance mode, and VMware Storage VMotion™ make it possible to move running workloads from one physical server to another without downtime or service interruption, enabling zero-downtime hardware maintenance.

Depending on what type of failure you are defining a plan for, do it properly. For SRM create an appropriate Run book. This will be used during a site failure. For host upgrades, make a plan to vMotion all the VMs and ensure there are available resources for all the VMs with one host down, then update the host. For VM maintenance take a snapshot and then revert back if the VM upgrade didn’t go well.

8. Prioritize each service in the Service Catalog according to availability requirements.

Using VMware HA set the reboot priority depending on the availability requirements. Most important Services/VMs can have the highest priority during an HA failover

VM Restart Priority Setting

VM restart priority determines the relative order in which virtual machines are restarted after a host failure.Such virtual machines are restarted sequentially on new hosts, with the highest priority virtual machines first and continuing to those with lower priority until all virtual machines are restarted or no more cluster resources are available.

9. Balance availability requirements with other infrastructure qualities

VMware also helps protect against unplanned downtime from common failures, including:

Network and storage interface failures. Support for redundant network and storage interfaces is built into VMware ESX™. Redundant network and storage interface cards can be shared by multiple virtual machines on a server, reducing the cost of implementing redundancy. VMware virtualization also makes it easy to create redundant servers without additional hardware purchases by allowing for the provisioning of virtual machines to existing underutilized servers.

Server failures. VMware High Availability (HA) and VMware Fault Tolerance deliver protection against server failures without the cost and complexity often associated with implementing and maintaining traditional solutions. VMware HA automatically restarts virtual machines affected by server failures on other servers to reduce downtime from such failures to minutes, while VMware Fault Tolerance ensures continuous availability for virtual machines by using VMware vLockstep technology to create a live shadow instance of a virtual machine on another server and allow instantaneous, stateful failover between the two instances.

Overloaded servers. VMware VMotion, VMware Distributed Resource Scheduler (DRS), and VMware Storage VMotion help you to proactively balance workloads across a pool of servers and storage.

Objective 2.4 – Build Manageability Requirements into the Logical Design


1. Understand what management services are provided by VMware solutions.

Not an exhaustive list and I will only be using a few of them in my lab.

vMA, vCenter, PowerCLI, vCLI, vCenter Orchestrator, vSphere API, vSphere HA, vSphere DRS, Auto Deploy, Scheduled Tasks, Host Profiles.

2. Identify and differentiate infrastructure qualities (Availability, Manageability, Performance, Recoverability, Security)

Already covered this in objective 2.3

Skills and Abilities

3. Build interfaces to existing operations practices into the logical design

This is talking about integrating existing services such as an existing Database or Active Directory in to the logical desgin, obviously I can’t apply this to my design.

4. Address identified operational readiness deficiencies

Again I can’t apply this to my design but it’s referring to issues that we’re picked up during the discovery phase that need to be fixed as part of the new design.

5. Define Event, Incident and Problem Management practices

ITIL Definitions

  • Event – A Change of state which might have an influence for the management of a service or system
  • Incident – An event which is not part of standard operation and usually causes a service disruption to degrade functionality
  • Problem – The cause of one or more incidents

6. Define Release Management practices

ITIL Definition

Release Management encompasses the planning, design, build, configuration and testing of hardware and software releases to create a defined set of release components.

The goal of the Release and Deployment Management process is to assemble and position all aspects of services into production and establish effective use of new or changed services.
Effective release and deployment delivers significant business value by delivering changes at optimized speed, risk and cost, and offering a consistent, appropriate and auditable implementation of usable and useful business services.
Release and Deployment Management covers the whole assembly and implementation of new/changed services for operational use, from release planning through to early life support

7. Determine Request Fulfillment processes

More stuff from ITIL

Each catalog item uses a fulfillment process, to define the request fulfillment process when that item is ordered.

Fulfillment processes are used when ordering standard catalog items, but are not used for some extended types of catalog item, such as content items.

8. Design Service Asset and Configuration Management (CMDB) systems

  • SACM supports the business by providing accurate information and control across all assets and relationships that make up an organization’s infrastructure.
  • The purpose of SACM is to identify, control and account for service assets and configuration items (CI), protecting and ensuring their integrity across the service lifecycle.
  • The scope of SACM also extends to non-IT assets and to internal and external service providers, where shared assets need to be controlled.
  • To manage large and complex IT services and infrastructures, SACM requiresthe use of a supporting system known as the Configuration Management System (CMS)

9. Define Change Management processes

Change management is an IT service management discipline. The objective of change management in this context is to ensure that standardized methods and procedures are used for efficient and prompt handling of all changes to control IT infrastructure, in order to minimize the number and impact of any related incidents upon service. Changes in the IT infrastructure may arise reactively in response to problems or externally imposed requirements, e.g. legislative changes, or proactively from seeking improved efficiency and effectiveness or to enable or reflect business initiatives, or from programs, projects or service improvement initiatives. Change Management can ensure standardized methods, processes and procedures which are used for all changes, facilitate efficient and prompt handling of all changes, and maintain the proper balance between the need for change and the potential detrimental impact of changes.

10. Based on customer requirements, identify required reporting assets and processes

I’m not entirely sure what this is referring to, need to do some more research!!!


VCAP DCD Study – Home Lab Design Part 2


Section 2 – Create a vSphere Logical Design from an Existing Conceptual Design


Objective 2.1 –Map Business Requirements to the Logical Design

1.Explain the common components of logical design.

The Logical Design specifies the relationship between all components, the components of my lab design are quite straightforward and comprise of 2 wireless routers, a smart switch, 2 ESXi hosts, 1 NAS drive and some ethernet cabling.

2.List the detailed steps that go into the makeup of a common logical design.

The steps involve gathering the requirements and creating a logical diagram that visually displays what needs to be built to fulfill those requirements.

3. Differentiate functional and non-functional requirements for the design.

I  struggle with these concepts and the reference material in the blueprint doesn’t really help, it talks about heart rate and blood pressure !!!! I wish they would relate the material to the technology we are studying, it might just be the way that my brain works but I need things spelled out in black in white.  Hey VMware…give us some solid examples that we can compare to our every day working lives please.

The definition for a functional requirement specifies what the system should do: “A requirement specifies a function that a system or component must be able to perform”
Functional requirements specify specific behavior or functions, for example:

Functional Requirements

  • The lab environment must be securely accessible from external sources but only accessible to the administrator.
  • Authentication must be validated through Microsoft Active Directory and VMware SSO.
  • The Lab should be able to support at least a vCenter Server, MS SQL Express database, and active directory server and an Update Manager.
  • VLAN tagging must be available on the switching infrastructure to separate traffic types.

Non-Functional Requirements

  • The vCenter Server and Database need to have some redundancy within the cluster.
  • Costs must be kept below £1500.
  • There should be enough compute resource to cater for vCenter Server, MSSQL Express, AD and Update Manager.
  • The design must use and existing IOMEGA NAS device.
  • Hosts need to be patched on a regular basis and kept in a consistent configuration.
  • Space is at a premium so the physical footprint of the equipment needs to be a small as possible.
  • Power consumption needs to be low.


Skills and Abilities

4. Build non-functional requirements into a specific logical design.

Here’s a non-functional logical diagram depicting the use of the IOMEG NAS device.


5. Translate given business requirements and the current state of a customer environment into a logical design.

Logical Diagram to follow…..

6. Create a Service Catalog

A service catalog is introduced from ITIL and should contain the items below.

  • Service name

Home lab Support

  • Service description

Maintenance and support will be included for the following devices..

2 x HP Micro Servers with ESXi 5.5 installed

1 x Virgin SuperHub

1 x Asus RT-N66U Wireless Router

1 x TP-Link Smart Switch


  • Services included

Patch management


Incident support

  • Services not included

Tea and Coffee making

  • Services availability



Objective 2.2 – Map Service Dependencies

1. Identify basic service dependencies for infrastructure and application services.

As this is a green field site there is no need for application discovery and application mapping, if needed I can do this using VMware vCenter Application Discovery Manager.  For the purpose of the Exam blueprint below are the discovery methods.

  • Active – uses common network protocols to remotely query servers to build up an overall picture, it can put a burden on network resources and doesn’t give any relationship data. It doesn’t require agents.
  • Passive – provides more relationship data than the above active discovery, it listens and samples network traffic to see how network hosts and servers talk to each other and on what ports. Does require agents.
  • Analytics – complements the above 2 by performing deep packet analysis of observed traffic.

vCenter Server is dependent the MSSQL database and SSO

SSO is dependent on Active Directory

MSSQL is dependent on Active Directory as I’ll be using service accounts for the database.

Skills and Abilities
2. Document service relationships and dependencies (Entity Relationship Diagrams)

An application dependency diagram determines which entities are related with another. While discovering running services during the current state analysis you can use this information to draw down the upstream and downstream relationships. Relationships could be defined in the following terms:

  • runs on / runs
  • depends on / used by
  • contains / contained by
  • hosts / hosted by


3. Identify interfaces to existing business processes and define new business processes

Doesn’t really apply to this design but if in the real world during the discovery process if something was discovered that needed to be changed as part of the design and will impact the way the environment is to be managed, then the new process needs to be documented.

4. Given a scenario, identify logical components that have dependencies on certain services.

Covered this above.
5. Include service dependencies in a vSphere 5.x logical design.

Not really sure what to say about this, but I will be including the service dependencies in the logical design.

6. Analyze services to identify upstream and downstream service dependencies.

Everything that happens downstream can have an effect on upstream items. For example, if the SQL database crashes, the vCenter will stop. 

7. Having navigated logical components and their interdependencies, make decisions based upon all service relationships.

I’m assuming they are talking about grouping virtual machines together using VAPPs but I don’t plan to do this in my design.

So that’s the first 2 objectives of section 2 in the blue print addressed, objective 2.3 and onwards will be covered in the next post.


VCAP DCD Study – Home Lab Design Part 1

My objective is to design and implement a home lab using the VCAP DCD Exam Blueprint as a guide, once the home lab has been deployed I will use it for VCAP DCA study.

I will try  to address each of the skills and abilities defined in the objectives, I might not be able to relate my lab design to all of the blue print objectives, but I’ll try and cover them as best I can.  I’ll be using the blog as my study notes so it might be a bit rough around the edges, once the exam is done I’ll come back pretty everything up!  I’ve used various sources for my notes, mostly I’ve used the documents provided in the blue print, I’ve also leaned heavily on the vBrownbag notes so a BIG Thanks to Shane Williford and Cody Bunch.

Section 1 – Create a vSphere Conceptual Design

Objective 1.1 – Gather and analyze business requirements

1. Associate a stakeholder with the information that needs to be collected.

Before  a design can begin the correct information needs to be collected, this information needs to be collected and associated with particular stakeholders. In this case I am the sole stakeholder.

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

This is a green field deployment, however, if it were an existing site we would do the following…

    • Perform current state analysis with tools like VMware Capacity Planner
    • Review the current environment documentation
    • Collected information from stakeholders and SMEs

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

  • Goals (why are we doing this and what is the time frame)
  • Scope (Whats included, whats not included)


  • Business (cost savings, work force reductions)
  • Technical ( Uptime, consolidation, DR)
  • Legislative ( compliance, security)
  • Assumptions ( sufficient cooling for hardware in datacenter)
  • Constraints (Must be done – re-use of existing servers or must be HP branded)
  • Risks ( could prevent the project from happening like budget not yet approved or a dependency on another project


4. Identify the need for and apply requirements tracking.

Requirements will be tracked in my design

5 .Given results of a requirements gathering survey, identify requirements for a conceptual design.

network reqs

storage reqs

 6. Categorize requirements by infrastructure qualities to prepare for logical design requirements
Note: There are no DR requirements for this design.
avail reqs
man reqs

Objective 1.2 – Gather and analyze application requirements

1. Given a scenario, gather and analyze application requirements

Application requirements are minimal for this deployment, all I require is vCenter Server, MS SQL Express and Update Manager.

2. Given a set of applications within a physical environment, determine the requirements for virtualization.

No P2V required for this project.

3. Gather information needed in order to identify application dependencies.

vCenter Server  and update Manager will be dependent on the MSSQL database.

vCenter Server will also be dependent on SSO and Active Directory as I will be using service accounts.

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

Application requirements are nothing out of the ordinary and will not have a major impact on the overall design.

Objective 1.3 – Determine Risks, Constraints, and Assumptions

1. Differentiate between the general concepts of a risk, a requirement, a constraint, and an assumption.





2. Given a statement, determine whether it is a risk, requirement, a constraint, or an assumption.

I’ve think the previous point covers this.

3. Analyze impact of VMware best practices to identified risks, constraints, and assumptions

I don’t see VMware best practices having an impact on my risks, constraints and assumptions.

VCAP DCD – My Study Approach

So I’ve decided to re-attempt the VCAP-DCD 5.5 after failing my first attempt at the 5.0/5.1 version of the exam.  It’s been well documented on various blogs that the exam is difficult to prepare for if you don’t do design work on a regular basis.  I’ve been involved in the design and deployment of many projects from small 4 host clusters to large scale cloud deployments, I’ve also been lucky enough to work with some good guys from VMware PSO as well as some very clever individuals in my current organisation, so I would like to think that I’ve had a reasonable amount of design experience.   It soon became apparent in the exam that I was lacking on the process side of things, I’m pretty much ok with the technical side but when it came to pigeon holing  risks, constraints, functional requirements etc etc… I struggled as I found it to be quite subjective and the answers could have easily fitted into several categories, anyway I ran out of time in the exam and missed it by 24 points.

This time around I’ve decided to take a slightly different approach to my study, the aim is to pass the DCD and the DCA in 3 months!  I currently don’t have a home lab as I have access to equipment at work, so using the DCD exam blue print as an architectural blue print I intend to design and deploy a home lab for the sole purpose of DCA study, killing two birds with one stone I suppose.  I’ll blog each stage of my mini project as I work through the phases.



Isolated PVLANS will not work with Cisco UCS and VMware vDS

This is something  I came up against several years ago but never got around to posting it, the workaround is to deploy a Nexus1000v, the PVLANs will be defined within the Nexus and will never traverse the upstream network.

Here’s the response from Cisco

“In a nutshell in End Host mode on the Fabric Interconnects have no unknown unicast flooding functionality and does not learn Mac addresses on the uplinks.

Because the Vmware DVS cannot terminate the PVLANs they will need to extend into the external LAN switching infrastructure.
Therefore, all community/isolated VLANs have to be defined on UCS and on the external LAN switch(es) as well.

This is fine if no communication is required between the isolated PVLAN and any external host on the Primary VLAN.

Where the design requires an external promiscuous port then you need to set the UCS Fabric Interconnects in switch mode. That is traffic that enters the promiscuous port is classified in the primary VLAN. Therefore from a UCS perspective there are no server-side MAC-table entries in the primary VLAN because servers are in an isolated PVLAN. So no communication is possible.

As such, switch mode is a must for bi-directional communication. Here the fabric interconnects will do Mac-Learning on the uplink ports as well as the server ports.”