Tag Archives: vSphere 5.1
Today I received a message from VMware Education Services introducing a new way for current VCP holders to refresh or re-certify before their VCP expires. Currently as it stands, anyone holding a VCP certification prior to March 10, 2013 has only until March 10, 2015 to re-certify using one of the following methods.
- Take the most current VCP exam in any of the available tracks (Datacenter Virtualization, Cloud and Desktop – not sure if Network Virtualization qualifies for this or not). No matter which track you held your VCP in, all will be refreshed with another two years.
- Take an advanced level exam, meaning the VCAP DCA or VCAP DCD. Not only will you advance to the next level, you will refresh your VCP expiration as well.
Prior to today, these were your options. Now however all you VCP holders have a third option, so long as you are currently hold the VCP5-DCV status.
What is a delta exam?
This is something new to VMware certifications. Basically, this exam is based only on the differences between vSphere 5.0/5.1 and the vSphere 5.5 exams. Also, instead of your normal 135 questions the delta exam will only have 65. The biggest difference is how the exam is delivered – you won’t need to drive to a testing center for this one, it is being offered online through Pearson Vue – and I’m assuming this will be a similar fashion to that of the VCA delivery. Another noticeable difference is price – this one, coming in at $120 USD instead of the normal $220 USD.
Is it worth it?
This is something I can’t answer for you – you will have to go through the scenarios in your head. Currently I have an expiry date of January 2016 for my VCP5 and honestly I’d rather sit a new version of the VCAP then do the VCP again. That said, can I expect a VCAP6-DCA to be available by Jan 2016? I have no idea! Do I want to risk the chance of losing my VCP due to no new VCAP exam coming out or possibly failing the VCAP when it does come out? It’s all a giant kerfuffle in my head right now! One note, the email I received said it was only available to those who need to renew their VCP before March 10, 2015. As noted above, mine was extended to Jan 2016 due the completion of my VCAP in January of this year. That said, I went through the process of being authorized for this delta exam and had no issues getting into the portion of the Pearson Vue site which allows me to schedule it. So, try for yourself I guess!
Time’s a wastin!
Oh yah, better hurry and make your mind up. This delta exam will only be available until November 30th, 2014! So you have just less than a couple of months to figure out what you are going to do! Honestly, this whole re-certification process just confuses and puts me in a bad mood Nonetheless, though I’d share the news! Oh, I tried to use the VMUG Advantage VCP discount code – didn’t work!
A few weeks ago I released a post in regards to my finishing of the Troubleshooting vSphere Storage book. This has been a lot of work and I’ve had a lot of help from the community in getting this book completed.
Writing a book is not a simple task. It involves research, lab time, and focus. And then there is the editing, both grammatically and technically – which can be even more work than the writing itself!
I tried to gear this book towards the vSphere Admin. The “jack of all trades” system administrator. Hopefully readers will find the knowledge and how to within the book to solve common storage issues that tend to spring up within a vSphere environment. The book is broken into three main subjects of focus; troubleshooting connectivity, troubleshooting contention and troubleshooting capacity. If you’d like to purchase the book you can do so by visiting the landing page on Packt’s website and following the various channels.
Tis the season for winning
That said – Tis the season right? The season for giving! That’s why I’m happy to announce that I have three eBook versions of Troubleshooting vSphere Storage to giveaway over the next week or so. A little light reading to enjoy over the xmas holidays!
As you can see by the little widget below, I’ve opted to use PunchTab to gather the entries for this contest. It’s hectic trying to follow Twitter hashtags and what not so I thought “Hey, why not use a CaaS (contest as a service) solution. Sorry for all the PunchTab branding but this is what you get when you use a free service 🙂
So how do you enter? It’s easy, leave a comment, send a tweet and follow me! That will get you three entries! Just make sure you do it through the widget below. I’ll have PunchTab pick three random winners at the end of the contest (end of Sunday, December 15th) and announce the winners shortly thereafter. Good luck and let me know what you think of the book!
So here we are – Part 3 and the final part of the Linux series. The title of this part is /usr/bin/random because well the content will be indeed quite random. I couldn't think of a way to classify the content of this post into a single category! So get ready for a hodge podge of fixes, modifications and configurations that have nothing in common and no similarities whatsoever. I apologize up front for the flow (or lack thereof) of this post but hopefully someone will find something useful in it.
What time is it?
Almost every OS is very dependent in having accurate time and use different hardware and software techniques to do so. When something is virtualized this adds yet another layer in between the OS and the hardware and creates some challenges as it pertains to timekeeping. I’m not going to go through a time keeping lesson – there’s a great VMware whitepaper here that goes very deep into the topic. Instead I'll just try to summarize what I've learned over the years as it relates to Linux and timekeeping. Depending on the Linux distribution and kernel version you are running you may need to add some boot parameters to either the grub or LILO menu in order to disable the High Precision Event Timer (HPET) and set the proper clock managers. Most new releases of Linux distributions (within the last couple of years) don’t require any changes, but for instance, if you are running Debian 4.x you would need to append “divider=10 clocksource=acpi_pm” to your kernel boot line. For a full list of available options have a look at KB1006427 from VMware.
The I/O Schedule
ESXi has its' own special sauce as it pertains to scheduling disk I/O – and so does Linux. Linux has some different I/O schedulers built into the OS, such as NOOP (noop), Completely Fair Queuing (cfq), Anticipatory (anticipatory), and Deadline (deadline). By default, as of kernel 2.6, most Linux distributions use CFQ as their I/O scheduler of choice – not really a problem in the physical world but as a guest OS can cause some performance degradation. As stated earlier, ESXi has its' own I/O scheduling, so does it really make sense to schedule I/O at the guest OS level, and then at the hypervisor level? Probably not! That's why there is a VMware KB article that states to switch your I/O scheduler to noop or deadline. Honesty I would switch to noop as it does nothing to optimize and disk I/O, which would allow the hypervisor to do its thing. Here's how!
You can change the scheduler during runtime by echoing to the proper disk, IE for sda we would use
echo noop > /sys/block/sda/queue/scheduler
However, to permanently switch you need to add an elevator switch to your grub kernel entry in grub or your Linux entry in grub2. The above will reset back to cfq on reboot. To permanently do this your kernel entry in the grub menu should look similar to the following (menu.lst for Grub and grub.cfg for Grub2). Below is Grub2.
linux /boot/vmlinuz-2.6.32-5-686 root=UUID=b62a38cf-8917-484a-9a96-d5a74beb8d59 ro quiet elevator=noop
Copy the floppy!
In Part 2 we went over how to completely get rid of the floppy drive. Part of those instructions included blacklisting the floppy module inside of /etc/modprobe.d/ – well guess what? There are a slew of other modules that are loaded by default that you will probably never use when running a virtualized instance of Linux. Below is a list of modules that I often blacklist – Sure, there are the one off cases where you will need one or two of these modules loaded so just pick and chose for yourself…
floppy – Take a guess, yup you got it, the floppy drive 🙂
mptctl – This monitors your RAID configuration. I don't normally RAID inside of my Linux guests so this is really not needed – also this will spam up your messages log quite a bit as well.
pcspkr, snd_pcm, snd_page_alloc, snd_timer, snd, soundcore – These all have to do with sound which I'm not even sure is possible. Disable them!
coretemp – if you don't care how hot your vCPU's are running you are safe to disable this. If you do care, then, well, I'm not sure what to tell you 🙂
parport, parport_pc – these have to do with your parrallel ports. I've never used these and always blacklist them.
Virtual Consoles – Do you even use them?
If you ware wondering how can I even use them inside of vSphere – check out my post here. If you don't use them, why leave them enabled? Disabling them is pretty easy, just comment out the tty# lines in /etc/inittab – I always tend to leave the lines in the file and just place a '#' in front of the ones I don't need – below you can see an example of my initttab files. As you can see I left one console activated.
1:2345:respawn:/sbin/getty 38400 tty1
2:23:respawn:/sbin/getty 38400 tty2
#3:23:respawn:/sbin/getty 38400 tty3
#4:23:respawn:/sbin/getty 38400 tty4
#5:23:respawn:/sbin/getty 38400 tty5
#6:23:respawn:/sbin/getty 38400 tty6
So that's really all I can think of that in terms of tips and tricks that I do when deploying a Linux guest on vSphere. I'm sure there are many others. Linux and vSphere both have a ton of advanced settings and are very flexible when it comes to tuning for performance so if you know of any that I've missed I'd love to hear about them, just leave them in the comments box below. By no means am I a Linux expert and I'm always eager to learn 🙂 Thanks for reading!
Part 3 – /usr/bin/random
Alright – so in Part 1 we covered LVM, partitioning and the basic installation of our VM. Now its time to tackle a few key points as it pertains to virtual hardware. Now there isn't a whole lot to cover here and honesty I'm just going to graze the surface on some of these topics. You will find a bunch of links to some KB articles and white papers where you can go pretty deep on some of these topics so feel free to read them as well. Again, leave all of your feedback and comments in the sections outlined below – it's a learning process for us all 🙂 So, let's get into it!
Use the virtualized hardware!
VMXNET3 right! Hopefully by now you know of the advantages of using the VMXNET 3 adapter – most of those same advantages apply to Linux as well. I’d definitely recommend using this. Since one of the benefits of VMXNET is the RSS or Multiqueuing it makes sense to use it, however there are a few things to keep in mind when utilizing this with the VMXNET3 driver; Any modern Linux kernel will now have it’s own built in VMXNET3 driver/module and for the most part (I think by default) your VM will use it, even if you have VMware Tools installed. – and this is fine. There are times however where you might want to use the driver which is included with VMware Tools. If you are running an older Linux kernel then the version of VMXNET3 you have might not support RSS or Multiqueueing, therefore you might want to use the VMware version which does. To do so you can run the following command to replace the kernel driver with the VMware provided driver from the VMware Tools install package.
Go head and check out KB 2020567 for a bit more information on this. Just remember, newer kernel = do nothing, older kernel = run the command above.
Who wouldn't want to be paravirtual?
Hey sounds cool right! I know I'd want to be paravirtual! Well your virtual SCSI controller does too! PVSCSI has been the recommended adapter of choice for a little while now and can provide you with a multitude of benefits such as higher throughput at a lower CPU cost! That being said, you need to be sure you are on a supported OS list! When it boils down to it, so long as you are running at least 2.6.33 of the Linux kernel and have the vmw_pvscsi driver you should be ok, but, for those that like to be officially supported, the list is here.
Manage that memory!
Its always best practice to right-size your VMs. Keeping an eye on what CPU and memory resources are being utilized, knowing your workloads and sizing it appropriately – a Linux VM is no different (Hey, we are VMs too you know). There is one setting from within a Linux VM that can be changed and tweaked to help though – swappiness! Yup I said it, swappiness! As always, open source and Linux never fail to amuse me with their terms and names for things! So swappiness is essentially an integer value that determines when to move memory pages from physical memory( which is really virtual now, just mapped to physical) to your local swap. Sounds cool eh but there is a catch! Linux will move pages to swap even if you have physical memory available and this is completely separated from the fact that vSphere will also do its' own memory swapping if need be. To cut to the chase a high swappiness value indicates that processes are more likely to to be swapped, whereas a low value indicates the kernel will leave them be. The default value I've seen the most is 60 – normally I like to change this to somewhere around 15-20. This is done by executing the following command
Echo 15 > /proc/sys/vm/swappiness
This works great for the current running state but to persist across reboots you will need to add the "Vm.swappiness=15" somewhere inside of /etc/sysctl.conf
Useless Hardware – Get rid of it!
Do you honestly ever plan on using that floppy disk? Didn't think so – get rid of it! This is a process I try and apply to all my VMs not just the Linux ones. Unneeded hardware can tie up not only vSphere resources but your OS resources as well. So in terms of floppy it's not just as simple as just removing it from the VMs settings – you will need to also disable it from the BIOS of the VM. If not you will always see that crazy floppy error that flashes up when grub is booting (the one on the right). And even further, remove and blacklist the floppy module and prevent it from even loading into the Linux OS. If you perform an 'lsmod | grep floppy' you will see that even though you have removed it from the VM and disabled it in the BIOS, the module still loads. To completely blacklist a module from loading simply add it to a blacklist file in /etc/modprobe.d/ – In the case of the floppy we can execute the following list of commands to remove all traces of that pesky disk!
Echo "blacklist floppy" | tee /etc/modprobe.d/blacklist-floppy.conf Rmmod floppy Update-initramfs -u
So, that's it for now! As with anything you do in production be sure to test it first! Try different swappiness values, keep an eye on your resource usage and adjust as needed! If you have any other tips/tricks for a Linux VM please leave them in the comments section below! I'd love to hear them! Next up in this series we will look at a bunch of random things like timekeeping, the i/o scheduler, as well as some other modules that we probably don't require when running virtualized! Stay tuned and thanks for reading!
Part 2 – Virtual Hardware
Today VMware has introduced the world to VMware vCenter Log Insight, labeling it as a "new automated log management and analytics product for the cloud era". In my opinion this is a great next step for VMware's management portfolio and if integrated correctly, could really compliment the analytics and performance data crunched by VMware vCenter Operations.
More than just syslog?
From what I have seen, YES! Although the underlying technology utilizes syslog collectors/receivers to receive the data, the visualizations and dashboards by which that data is presented to the end user is really where the value resides. On average an ESXi host will dump roughly 250MB of data per day. That's 250MB of data, that you, the end-user will need to parse and correlate line by line to try and make some sense out it. I know I only understand about 25% (if that) of what is spit out in some of those logs. vCenter Log Insight takes this data and with what they call 'content packs', presents the user with a bunch of predefined dashboards of some of the most relevant data that you may be looking for, along with common links to KB articles if any.
Easy transition from monitoring to troubleshooting
Hopefully we have all seen the power of vCenter Operations; How it correlates and analyzes all that data to really help us drill down and find out where any current (or future) problems exist. If the issues are not evident, or if we are still unure of what the problem still is, the next viable step would be to jump into our logs to see what information we can find there. With integration between vCOPs and vCenter Log Insight hopefully this will make that transition from our monitoring solutions into our log analyzing solutions a whole lot easier. Again, saving us time and helping us discover root causes that much quicker.
Even more for advanced users
For those that love to look at the raw log data (huh?!?!?!) you can do that as well. A search type functionality, similar to that of Splunk is available as well. Use this to parse and filter through all of your logs that vCenter Log Insight collects. The main difference here is there is no need to learn any new "languages" to drill around in and query your data. VMware seems to have really made a big effort to keep this product simple and easy to use, but powerful and extendable at the same time. Also, the ability to generate alerts and send email notifications on a custom query is a very nice functionality to have.
More than just ESXi and vCenter
As mentioned above visualizations and presentations are provided by content packs. These are easily exported and imported to and from vCenter Log Insight, in turn allowing third parties (including YOU) to easily develop, distribute and share. So, hopefully, within time, we will see more than just ESXi and vCenter logs getting pumped into this. On that note, we will probably see more than just VMware products being analyzed. In my opinion the community will really need to take the lead on this one, and looking at past performance that the VMware community has, I'm sure they will!
So VMware says to expect to see some sort of GA in Q3 of this year, I'll let you guess the timeframe! I hope to get a few more posts out about vCenter Log Insight as I delve more into the product but for now you can find some here, here and here. Have a look for yourself and let me know if you think!
OK! Finally the end of this series! Honestly without the existence of the following resources there is no chance in hell that I would have been able to even develop a simple workflow, let along start scripting and what not. I was a couple weeks into vCO before I even learned that you can switch to ‘design’ mode 😉
So, if you are looking for some awesomeness on vCO, have a look at the following…
Official vCenter Orchestrator Documentation – Should really be your first go to reference for all that is vCO
Automating vSphere with VMware vCenter Orchestrator – Although official docs SHOULD be your first go to item – I find that this book written by Cody Bunch actually IS my first go to reference.
www.vcoteam.info – Great blog with a ton of script examples and whatnot! Bookmark this…
www.vcoportal.de – Ditto to the above line, might better bookmark this on while you in your bookmarks…This is a fabulous blog!
VMware vCenter Orchestrator blog – the official blog from VMware centered around vCO.
VMware API and SDK documentation – this always helps when trying to determine what type of objects or properties any given function requires.
Good Ol’ Twitter – Follow @cody_bunch, @josh_atwell, @vCOteam, @technicalvalues – there are a ton more but these are the ones that I can think of off the top of my head – just search for #vCO and find someone to ask your question to – community seems to be always willing to help.
Thanks for reading and hopefully you can find some usefulness out of vCO as I did! I encourage everyone to explore what it has to offer, which the same results, everytime! Check out the full series below…
My first vCenter Orchestrator Workflow