There are different schools of thought as to whether you should have SSH enabled on your hosts. VMware recommend it is disabled. With SSH disabled there is no possibility of attack, so that’s the “most secure” option. Of course in the real world there’s a balance between “most secure” and “usability” (e.g. the most secure host is powered off and physically isolated from the network, but you can’t run any workloads ). My preferred route is to have it enabled but locked down.
Note: VMware use the term “ESXi Shell”, most of us would term it “SSH” – the two are used interchangeably in this article although there is a slight difference. You can have the ESXi Shell enabled but SSH disabled – this means you can access the shell via the DCUI. For the sake of this article assume ESXi Shell and SSH are the same.
Today was always going to be a bit of a funny day as I scheduled the VCAP5-DCD exam for 10am this morning. I am happy to say that I passed! I’m a bit light on VMworld to report today, so forgive my DCD experience to pad it out!
I have to confess my prep for this exam was light – I literally only watched the TrainSignal course by Scott Lowe (@scott_lowe) and just about finished that last night in the hotel! I don’t spend much time focussing on design during my day job, so I approached this exam as a bit of a learning experience rather than a serious bid to pass. I decided to book the exam here at VMworld just because you can get 75% off – if you’re funding yourself it’s not a discount to be dismissed easily!
Taking the exam
As with the DCA exam the DCD is a gruelling 4 hours, with 100 questions of which normally around 6 are Visio style designs. Again, same as the DCA, time management is massively important – I was actually so concerned with the time after running out in the DCA that I went probably too quickly and finished with 45 minutes to spare.
It’s also a very wordy exam – you have to read a lot of text and pull out the relevant info. On the one hand you need to read it very carefully to ensure you pick up the right requirements etc, and on the other you really need to read as fast as possible to keep on track time-wise. The technique I used was to find out what they were asking me for first, and then scan back through the text for the relevant information.
The Visio style questions are a bit clunky, and I’d definitely recommend using the demo of the interface that VMware provide to make sure you’re familiar with how it works – you don’t want to do a “Gregg” (ahem @GreggRobertson5, I am looking at you) and delete your whole diagram by accident.
There are absolutely loads of exam experiences out there to read up on – just Google “VCAP5-DCD exam experience” (though, probably, that’s how you ended up here). I used http://thesaffageek.co.uk/vsphere-5-study-resources/vcap5-dca-dcd/
TrainSignal (now PluralSight) – I am really lucky to have access to TrainSignal’s library via the vExpert program, but it’s such a good resource I’d definitely pay for it if I didn’t. The course I used was Designing VMware Infrastructure.
I have also read Scott Lowe’s Mastering VMware vSphere 5 which is a fantastic book, even if you’re not going to do the exam. If you plan on buying it you could always use the links in my booklist page
The rest of the day
After the exam I was pretty wrung out and needed a bit of time to recover – I’m still feeling the effects of the concentration now 3 hours later.
Hands On Labs
I spent some time doing hands on labs (HOL) this afternoon, specifically doing the vCAC v6 labs. I’ve been involved with the beta for “project nee” which is what the HOL were based on. The HOL infrastructure is huge here, with a full suite of desktops and a BYOD version. It’s pretty slick – at the time of writing there are over 28,000 VMs created in over 3,100 labs.
I braved the Solutions Exchange again after yesterdays car crash of a visit, determined this time that I would not let my badge get scanned by any pushy sales person. It was more tolerable this time, I got to the stands I was aiming for and was relatively un-harrassed.
I was happy to hand over my info to PernixData for a copy of the vSphere Design Pocketbook, especially as it’s got a contribution from DefinIT’s Simon Eady in it!
It’s impossible to explain how good it is to be able to talk to so many really awesome people who I am honoured to call peers – It’s great to chat with people who have similar goals and find out how and why they’re doing the things they are. For me that’s been one of the best parts of VMworld and I have learned at least as much through conversations with people as I have from the sessions.
Tonight is the VMworld Party, I am torn between going to that, and going to bed! Whatever I decide, tomorrow is a new day and I will be aiming to go to a few more sessions as well as keep on with the networking.
John Troyer (@jtroyer) asked a question on Twitter last night about a CloudCred prize of $1000-2000:
@jtroyer a nice lab setup!
— Sam McGeown (@sammcgeown) September 19, 2013
@jtroyer I guess a couple of hosts, storage and a switch, wouldn't get HCL certified for that but I'm sure it's doable!
— Sam McGeown (@sammcgeown) September 19, 2013
After my previous post about studying and the exam experience of the VCAP5-DCA exam (and 3 weeks of waking up to check my phone for the email all night) I am pleased to say that I received my Exam Score last week and it was a pass! I was really pleased to see that I passed with a very decent margin too, which was great! The rushed nature of the exam and long wait for the results leaves you going over the exam in your head convincing yourself how badly you’ve done, so it came as a huge relief and surprise.
Next up, VCAP5-DCD – possibly even at VMworld Barcelona given that there is 75% off exams for attendees taking them on-site.
DefinIT @ VMworld Barcelona
I’m also very excited to say that fellow DefinIT blogger Simon (@simoneady) and myself will be heading off to Barcelona in October to our very first VMworld conference. Regular readers may have seen Simon won a V.I.P Tweet competition earlier this year, which was fantastic. I threw my name in the ring for a vExpert Blogger pass and was slightly stunned and very pleased when I received an email saying I’d been selected to go. For both Simon and myself VMworld has been something we have both wanted to attend but never really had the opportunity before, so we’re really looking forward to it!
With the release of vCenter Log Insight Public Beta (http://communities.vmware.com/community/vmtn/vcenter/vcenter-log-insight) I thought I’d strike while the iron is hot and run through the installation and configuration.
Deploying the OVF
This is such a bread and butter task that it doesn’t require more than a few words – it’s definitely worth looking at the Sizing PDF before you deploy (VMware-vCenter-Log-Insight-1.0-Beta-Virtual-Appliance-Sizing.pdf) as it’s not small even for a test installation. If you’re using less than the recommended 8GB RAM there are additional steps to change the heap size for performance.
The vSphere UMDS provides a way to download patches for VMware servers that have an air-gap, or for some reason aren’t allowed to go out to the internet themselves – in my case a security policy prevented a DMZ vCenter Server from connecting to the internet directly. The solution is to use UMDS to download the updates to a 2nd server that was hosted in the DMZ and then update the vCenter Server from there. It also can save on bandwidth if you’re running multiple vCenter Servers, which again was the case (though bandwidth isn’t really a constraint).
Had a strange one after deploying an XP VM from a template today - the VM would not power on and threw the following error:
An error was received from the ESX host while powering on VM [VM name].
cpuid.coresPerSocket must be a number between 1 and 8
Digging around on google the error seemed to be related to over-allocating vCPUs (e.g. assigning 8 vCPUs on a VM with 4 physical CPU cores). This was a single vCPU machine on a 12 processor host, so not likely to be that! It did give me the idea that maybe the VMX had an error, so I edited the VM hardware and added an extra CPU and saved the config. I then edited it back to a single CPU and powered on the machine - it worked!
Examining the vmx showed that the coresPerSocket was set to zero which is incorrect:
cpuid.coresPerSocket = "0"
And after the change, the numvcpus setting was added and coresPerSocket updated:
cpuid.coresPerSocket = "1" numvcpus = "1"
Fortunately, it's a simple fix and once I'd updated the template, not something that will bother me again!
So VMware's Support Assistant is pretty awesome and it's free! I thought I'd do a quick run through of the installation and set up for anyone who was interested, it's fairly straightforward and if you raise a lot of calls or have multiple calls on the go it's a time saver!
VMware's official page for the Support Assistant is here - https://www.vmware.com/products/datacenter-virtualization/vcenter-support-assistant/overview.html