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Arvinth's Blog

8 posts

Its a pass again & earned VCIX-DCV. I should say that there was no too much struggle as many of us would have experienced during the DCA|DCD version 5/5.5 preparations & exams !! Many lab topics and objectives which was hard to achieve few years back using budget home labs are pretty easy to achieve in today's time with HOLs. And also the exam look & format is similar to HOL, hence it is really comfortable in taking up the exam.

 

Hints --> pretty much known to most of the candidates taking up VCAPs and I see that the count has increased a lot these days!! Though a point I will always stress is to book a first slot available & dont push it to the noon or close to EOD hours to avoid unexpected latency's

 

Materials listed below are really vital & played key role for me in getting myself equipped for taking up the VCAP6-DCV deploy exam !!

 

Overall its a perfect closure for this year & though I was getting chances in the Public clouds/DevOps related projects, I intentionally kept myself away from mastering those. The Only reason is ? thats the plan for Year 2018.

 

I Wish you all a wonderful new year & happy holidays !!

 

Regards,

Arvinth Rajkumar Ravi.

One of the toughest VCAP exam I would say. I promise if you are up to this certification then you will get to learn a lot from networking point of view and this is more than a VMware Advanced Lab exams as it involves lots of networking stuffs. Many VCIX-NV people had already talked a lot about the exam, formats and stuffs to concentrate so apart from those I have some points out of my experience.

 

  • Though we are going to cover the complete blueprint sections and we are 100% with the in and out of NSX-v, it is not going to be enough is what I've learned after giving the exam.
  • Spend a minute to read the question completely as I see for few labs understanding the topology is very much important to achieve the requirement.
  • I read somewhere in a blog when it has been mentioned that there are no dependencies between questions but it’s not 100% true of course there are some dependent questions
  • Use hands on labs as you like not only by following the lab manuals but also by trying out different topologies which will definitely help you for sure.

 

The study materials I used are..

 

The experience that we get starting from the preparation until giving the exam is really a fun, especially when the result is positive & thankfully I was able to tackle this big guy successfully.

 

Regards,

Arvinth Rajkumar Ravi.

Guys,

 

I had encountered an error during the VSphere environment upgrade to version 6.0. All components upgrade went smooth except the error I encountered after the ESXi host upgrade.

The host started reporting as "Deprecated VMFS volume(s) found on the host. Please consider upgrading volume(s) to the latest version".


I was not sure about why is this alert because I already upgraded my VMFS volumes to the latest version post Host upgrade  & the ESXi host hostd.log was also pointing to the same error.

I had restarted the ESXi host & after the reboot the alert was gone.

 

While browsing VMware KB's I came to know that this is a known issue & tagged as false positive & restarting of management agents itself will fix this it seems.

Cause for the issue has been detailed in the KB article KB2109735(http://kb.vmware.com/kb/2109735).

 

 

Regards,

Arvinth.

Might not be new, But had few calls from my colleagues about the VMNIC number change and they report its not working after changing it in the \device\ID location of esx.conf file.

So just thought of giving some head's up.

 

Firstly!! Yes the only supported & always recommended way for correcting the VMNIC numbering & order is by following the VMware KB 2019871.


But there are few circumstances that we could not follow the recommended way & on extremely exceptional situation we will be looking for the obvious option of changing the VMNIC order in the esx.conf file as required. I see few number of web contents, it is listed to change only the /devices/ID section which is not working.

 

Actually, there are almost 3 to 4 places including /devices/ID location you need to change in for VMNIC# in the esx.conf file. So the better way is

 

  • To download locally the esx.conf file using winscp from your esx server.
  • Open it with the word pad
  • Enter Ctrl + F and search for VMNIC#(# is the current NIC order number that you want to change to) one by one
  • Replace it with the desired NIC numbering until the search says that wordpad has finished searching the document. ( it should be 3 or 4 place you should have made the changes)
  • Once you are sure with the changes done, copy & replace the esx.conf in the esxi host using winscp. ( obviously keep a backup for worst-case)

 

Regards,

Arvinth Rajkumar Ravi.

Would like to share about an incident we faced with VCenter service start up issue & how it was resolved.


Last week there was VCenter service start up problem with my colleague's environment after it was upgraded to version 5.5 few days prior to the issue. While we start the VCenter service it was getting to a starting state and after few minutes to stopped state. No dmp file generated  by vpxd.exe crash, we carried out normal process, procedures step by step to troubleshoot the issue. By analyzing vpxd log, we confirmed that service is getting started initially and getting through the DB authentication as well. But finally getting terminated saying some directories could not be accessed  & we tried all possible ways and lastly we decided to re install VCenter server and map it to the existing SQL DB.

 

Before we proceeded, while trying out Google came to see that we can able to set the WER ( Windows Error reporting feature ) where it gets the application services crash dumps in general. By design or Luck  we had this feature enabled already in our VCenter server. Refer the LINK for complete configuration of WER ( https://msdn.microsoft.com/en-us/library/windows/desktop/bb787181(v=vs.85).aspx )

 

And as per the article we had a vpxd.dmp dump file in the configured location %LOCALAPPDATA%\CrashDumps.

On check the dumps, the logs matched with the VMWare KB http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2065630

 

The cause for the issue it has been said VCenter Server performs a validation on its Inventory data fails due to the excessive snapshots & as a workaround to change the <ThreadStackKb> size to 1024 in the vpxd.cfg file under thread pool section.

 

But we were not really sure if that is the case with the environment though we went and did the change as per the KB and it did the trick. We had 512Kb by default.

After it got fixed we carried out a check throughout the environment and found lots of VM’s running with snapshots & that is due to poor design of Roles & Permissions planning where users having full permissions on the VM’s doing all these nasty things. Finally environment was revisited with respect to roles and permissions & got the access restrictions applied.


Regards,

Arvinth Rajkumar Ravi.

Would like to share about the incident where this tool gave great hand :-)

 

previously we can capture packets only to the kernel interfaces using tcpdump-uw & cannot capture frames at the uplinks, or vSwitch levels, now it is possible for us to capture packets at VM virtual switch port level, physical uplinks level connected to any type of virtual switches using pktcap-uw utility.

 

how it is useful in a real time scenario ?

 

we had a very big problem that a critical app VM was suspected to have connectivity issues, client connections to the application VM was dropping & initially was not sure where it is happening, as usual severity raised with us for analysis. we used the pktcap utility to get the report @ virtual switch port level, and on the uplinks connected to the virtual switch level, and on reading the report using wireshark clearly proved that the client packets has not even reached physical uplink level and obviously nothing observed at virtual switch port level for the App VM.

 

its was a great help that the tool gave a way to isolate the issue is not within the virtual environment later it was passed on to network team and it was the firewall culprit. not digging much with the issue that we had, just want to emphasis that this tool came in handy to isolate that issue is with or not with vmware end.

 

below is the vmware KB providing end to end steps on how to execute it.

 

http://kb.vmware.com/kb/2051814

 

One point the way VMware listed to get the VM port id is lengthy using esxtop, instead easy way is using the esxcli way of getting it will list the port id as well the associated virtual  NIC mac connected to it, so as you make sure you are running the report for the right Virtualnic.

 

esxcli network vm list -> To get VM’s World ID

esxcli network vm port list -w 10930 --> to get the virtual port id and associated MAC of the virtual NIC

 

single line to capture packets at virtual switch port along with 2 uplinks connected to it as below.

"pktcap-uw --switchport 12345678 -o /vmfs/volumes/Testesx-Localstorage/VMname.pcap & pktcap-uw --uplink vmnic8 -o /vmfs/volumes/Testesx-Localstorage/Testesx_vmnic0.pcap & pktcap-uw --uplink vmnic9 -o /vmfs/volumes/Testesx-Localstorage/Testesx_vmnic1.pcap"

 

From above (switport , report storage location & uplinks alone to be changed) running this in a single go , we should have 3 reports VMname.pcap, Testesx_vmnic0.pcap & Testesx_vmnic1.pcap in the local storage of the esx host that is pointed in the command.

 

Important point: utility may not stop by pressing ctrl+c or ctrl+z so to stop it run the process kill command given in the article.

 

Regards,

Arvinth.

Arvinth Novice

Road to VCDX is open :-)

Posted by Arvinth Oct 19, 2014

Friends , this is a late post sharing my VCAP-DCD experience since i passed the exam in the month of July. I was engaged on my personal works that kept away from my laptop :-).

 

About the exam:- Tough yes, I am an administrator basically and not a designer, it took some time for me to sit for design exam since last October I cleared my VCAP-DCA to prepare myself to look at things like a designer. I think the time i took is good and I recommend not to rush, for me the slow transition worked out.


By this time all would have known with the structure and the pattern of the exam VDCD510  so there is nothing new i could say. But one important bug i noticed in the exam visio tool is " while i revisited to see the corrections i made with my design, BOOM BOOM My corrections was not there. still it was showing the old status" I had this on 2 design scenario's I worked. Not sure if this has fixed, So be careful and to revisit twice to see if the corrections you have made persist.

 

Obviously there is no end to say this preparation is enough for the exam, below are the materials i choosed and sticked to it & did not go vein.

 

  • VMware vSphere Design 2nd Edition Mar 2013 by Forbes Guthrie and Scott Lowe
  • VMware design workshop student manual
  • Train-signal videos on Designing VMware Infrastructure
  • Brown-bag video series
  • Talking about compute,network,storage designs with the design experts, Luckily i got a chance to sit for a small environment design.

 

I've started my preparations for VCDX. I learned that it needs tremendous amount of effort & knowledge, but I hope to achieve it.

Finally I wish you all the very best for the exam & good luck.

 

 

Regards,

Arvinth.

Arvinth Novice

My VCAP5-DCA experience :-)

Posted by Arvinth Oct 11, 2013

Hello Guys,

 

I recently sat for VCAP5-DCA exam & I am very glad to say that i have passed.  I have got the result yesterday 10/10/2013 since 10 days from the date of exam.  I know many experts out their shared their experience and knowledge on the study material they used for the exam preparation, yet i would also like to share mine especially few experts advice that has helped me a lot to achieve this.

 

As already known to everyone about the exam pattern, 26 Lab questions in 225 minutes along with 15 minutes for initial survey, I will quickly jump on to the useful points that helped me a lot.

 

 

I really found that maximum amount of time spent on practicals very helpful, so do as much as lab you can though you find as a repetitive its worth practicing again and again to get familiarized with the configuration.

As per the blueprint there are possibility for troubleshooting questions so practicing on configurations will help you to finish those very well within time and minutes saved gets added to spend for troubleshooting.

spend time on topics & steps to perform the tasks in details as you will have the points for steps though if the task has not been successfully completed.

 

Strategies for Taking the Exam


Book the very first slot during the day you decide to take the exam & reach 30 minutes well before the start of exam time to complete the formalities. ( I found the lab was very faster when i started the exam i was the only candidate in the center in the morning & person who wrote in the late afternoon on the same day was experiencing some slowness as bandwidth starts to fill.)

 

Great advice comes from a brief blog post by Alastair Cooke on the vBrownBag Site. Use the vSphere Client from the Launcher and not from an RDP session to the vCenter Server itself. Alastair thinks this would have saved him about half an hour. But trust me i followed the same , I could complete all 26 Labs before 30 to 40 minutes & had a better time to review the marked out left out steps or tasks.

 

Make sure to note down the tasks or questions that you leave for review in the sheet provided to you , that will help you to remember the things that you have left for later act.

 

There is a big gotcha with not completing questions or skipping questions. If you fail to complete a pre-requisite activity in a previous question you may not be able to complete a subsequent activity in another question. so be careful on this.

 

About my Own experience.

 

The exam questions to be excellent and a very valid test of real world administration skill. The outcome of the question is what is measured, not how you are going to the answer, assuming you implemented the objectives correctly. many part of labs will be broken which will be as they inform you during the start of exam as it is intentional. The end user experience of taking the exams is greatly improved, which is great news. I’m really glad that I went through the blueprint and reviewed the vBrownBag session as it directly contributed to me being able to answer correctly questions in the exam.

 

Finally my very best wishes for all those who are preparing & scheduled to takeup the exam.

 

Thankyou.

Arvinth.