“This is the whole point of technology. It creates an appetite for immortality on the one hand. It threatens universal extinction on the other. Technology is lust removed from nature.”
— Don DeLillo
The best feature of vDS is that its configuration is centralized to vCenter Server. In practice, it means that you create vDS and as you configure it, its changes are applicable to all connected hosts. You add a new host, just connect it to vDS, all port groups are already there. In just a few clicks, complete hosts networking is configured. You need a new network and VLAN, you just add a new port group and configure VLAN id. All hosts connected to vDS are gonna see it and all virtual machines can use it.
Distributed switch support private VLANs and standard switch do not.
vNetwork Standard Switch is available from VMware Infrastructure 3. It can be used without the vCenter server. vDS is supported by ESXi/ESX 4.x and higher. Hosts that belong to a dvSwitch do not need further configuration to be compliant.
Distributed switch or vDS provide similar functionality to standard switch or vSwitch. dvPortgroups is a set of dvPorts. The vDS equivalent of portgroups is a set of ports in a vSwitch. Configuration is inherited from dvSwitch to dvPortgroup, just as from vSwitch to Portgroup.
Virtual machines, Service Console interfaces (vswif), and VMKernel interfaces can be connected to dvPortgroups just as they could be connected to port groups in vSwitches.
There is a nice article regarding networking in Vmware at this link.
You have x hosts in your cluster managed by the vCenter server. If you are using standard switches, then you need to create a new switch for every new host joined to a cluster. If intended to add new VLAN you will need to create it on the every virtual switch at every host, using exactly the same name and VLAN number. It means x times doing the same job. It is time-consuming, and it offers space for a mistake. If the name is not exactly the same, live migration and high availability will not work. You can mitigate some of those problems by using the host profiles, but using distributed switches or vDS is the better option for many more reasons.
But what if you already have an infrastructure, with hundreds of virtual machines on standard switches? How would you change all VMs networking from standard to vDS? Let’s consider live migration as an option. Not to risk usurping your production network, maybe it would be logical to prepare one host separate from the production environment, and configure it to use vDS. Then, when having everything up and running and tested, start transferring VMs to a new host. You will face the first problem if you try live migration. Here is what you will get.
It means that vCenter will not allow you to do the live migration. You now have two options.
Option 2 is mandatory if you want to migrate your complete Vmware environment to vDS, and that includes the vCenter server. You can`t shut down vCenter server since without it you can not access vDS. It does not mean that all VMs will lose networking if vCenter gets unavailable, it just means that you can not switch between networks, or portgroups, without Vcenter Server. You will not be able to see or select ports available on vDS if you access host directly and try to do change networking of a VM that way. So if you have vCenter as a VM, here is the simple way to mitigate the problem.
This is the example with the standard virtual switch. On the left sides are port groups, and on the right side, we can see two physical adapters connected to switch. Just to mention, two adapters are there for redundancy.
In the next step, we remove one physical adapter from the standard switch. Due to fact that switch has one remaining adapter, networking works like a charm.
We have our new distributed switch prepared, with same portgroups (same VLANs).
In the next step physical adapter removed from standard switch should be assigned to the distributed switch. That way we create a host that can serve as a bridge for migrating VMs.
If there are unused physical ports on the server we can skip this removing and adding procedure, and use them for the distributed switch directly. So open distributed switch from networking selection chose to add a host to it and select the free physical adapter.
Then, it will give you the option to migrate some host virtual adapters, for the moment let it be, just click next without selecting any.
That`s it. Host now uses both standard and distributed switches.
Now that we have the host prepared, so we can try live migration.
After migration just remember to edit networking of a VM and change interface or interfaces to adequate port groups on the distributed switch. Doing that you will lose few pings, and that is it. You can use this way for all VMs including vCenter server, and even Database server if you have it on different VM.
When migrating second physical adapter from standard to distributed switch, you will probably have to migrate some of the host’s virtual network adapters. If that is the case, take a great care and doublecheck destination port group to be the same function as the source network. It may be the management network and you may lose connectivity to host.
If you have enough resources, the best way is to have one server configured as a so-called bridge, with both types of switches, and one with just a distributed switch as a final solution. So you live migrate VM to a bridge server than change its adapters to vDS portgroups, and then move the VM again to the host with only vDS. That way you are almost eliminating any possibility for a failure to happen. You repeat the process until one more host is without any VMs. Then you connect that host to a distributed switch and remove it from standard switch completely. Repeat the process until all VMs are on the hosts with a distributed switch as the networking device.
In most cases, you will not get in this kind of situation because distributed switch or switches are already in use on your Vmware environment. If you are setting up new vCenter and cluster from scratch, I strongly advise you to use vDS. By my humble experience, it is far better and easier to use and manage vDS than standard virtual switches, especially in bigger environments. The need for migration can emerge from older Vmware surroundings. Those kind of systems were typically many times upgraded and scaled from few to many hosts. If that is the case, working and managing standard switches can be a great deal of trouble, and this is the way that I figured to be the best solution for changing networking type.
Once again thank you for reading,
Posted in *.*
or domain name system. I`m quite sure that you would be delighted to type something like 188.8.131.52 in your browser’s address bar to open google.com. Well, without DNS you would need to. DNS is a service that translates names to IP addresses and vice versa. So, in fact, when you type a website address (for example tehcestigate.com) in your browser and hit Enter, your computer goes to another computer on the Internet, called DNS server and asks a question like: do you know what is the IP address of the techestigate.com? DNS server then searches its internal record list and if it finds the record it answers. If the record is not found internally the same question will be passed to another DNS server on a higher level. Having an answer DNS server passes it to your computer. The answer can be either the IP address of the domain or statement that the domain does not exist. In the first case, your browser will try to open the website, and in a second you will get a message like “This site can’t be reached” from your browser. This is a simplified explanation of DNS. Now to the subject of this article, ME TLD or Top Level Domain.
.me is the Internet country code top-level domain (ccTLD) for Montenegro.
Money always finds the way. The .me domain is definitely being advertised as a personalized domain. Montenegro may be selling its digital heritage but in its own unique way, this actually turned into the win-win situation for everyone. New, short and fun domain extension is out there, registrars are making money. Montenegro is making money. Just keep in mind that this is not the only case of using the language coincidence to monetize domain extensions. The Pacific Ocen island of Tuvalu is another example. Their .tv extension is advertised as domain names for broadcast media. There is also the island kingdom of Tonga with a .to extension used like where.to or go.to.
At the end as Shaldon would say: “Fun with flags.”
Here is the list of the most stupid domains ever:
I hope that this article was interesting and that it provided some fun and useful information. At least next time when you see some of the mentioned domains, you will know what they really stand for and even how do the flags of the originating countries look like.
Thank you for reading.
I was ten years old when I noticed that people around me started talking about us and them. I remember clearly a few situations when some older men asked me: “Kid, what are you?” It was at that time confusing and creepy question for me since I did not understand it. In most cases, I would ignore the question or just answer: “Human being”. When it happened a few times, I asked my parents to explain to me what is the trick with older people asking that weird question. (Later I figured out it was a question about religion). They said that people always try to find reasons to divide among each other and that both my answers were correct. Very soon people became divided by other ways. For example, there were those with electricity and those without it. It was wartime.
I lived in a city that had at the time around a quarter of a million people. Infrastructure was ok, for example, there was a big heating plant providing everyone with heating and warm water. I lived on the eighth floor of the building with around 50 apartments. Just try to imagine how it looks to walk to the eighth floor by the staircase without any light! Yes, the building was designed that way, and it was not meant for living in the stone age and without electricity. It had an elevator, but then again it also needs electricity to work. At first, we had some flashlights, but soon we were in a situation that there were no batteries in stores to purchase. Very soon there was no money for them anyway so the first problem could be ignored….. It was wartime.
The building had very bad insulation. It was hell during summer, and it was a fridge in winter. Without electricity, the fire was the only way of heating. Now that I`m thinking about it, it was the only way of cooking and heating water. So, in time when most of mankind progressed at warp 9, we were solving problems from the like stone age. The parents bought us a wood cooker.
It looked just like this and even had an oven. Our greatest and only home appliance that actually worked. It provided us with heat, enabled us to cook and to heat up some water for bathing. We were almost ready to survive.
Of course, the building did not have a chimney so we drilled a hole in an outside wall and put smoke pipe outside at the building facade. It was the only way, and everyone did it. Soon building with white facade became almost brown, black and gray. It would actually look great in a cheap post-apocalyptic movie. The whole city looked that way…. gray smoke and dark everywhere. But as I said before, now we got ourselves means of heating, cooking, baking bread and producing some hot water. If you would put big enough pot of water on a cooker and heat it near the boiling point, and then empty it in a bathtub and add some cold water, you could almost get a decent bath. In a great necessity, human ingenuity can be limitless.
So the next problem was providing firewood, and stockpiling it somewhere. Well, we had a small storage room in the basement of the building and a decent balcony, so some of the problems were solved. The next one was to buy firewood. It was very expensive, and there was little or no money at all. Anyway, very soon a new type of job and market arises from this trouble. There were horse wagons patrolling the city and selling firewood. Yes, I`m talking about 1993. year, it was not some western movie :). My parents would buy a wagon of wood and we would unload it in front of the building. Then, the fun would start, since it would need to be carried up to the eighth floor. We would start packing woods in a bags and carry some in the basement and some up the stairs. Great recreation huh?
At 1993. we were at the point where we would get electricity from the power grid for a few hours every….. 45 days. Yes, that was the on and off ratio. At least for us unlucky enough not to live in the same building with a politician or military officer. Those with that kind of neighbor did not have any power restrictions. Most of the people used candles, and candle market was expanding one. Imagine the whole city in the complete dark, and few scattered buildings shining like a Las Vegas in the dark. It was already possible to conclude that this situation will not end up well. People were leaving their homes and going somewhere. I think it is the first time that I heard word refugees.
The first and most common solution that did not involve light sources based on fire was a car battery (if you were lucky enough to have one) and a 12V light bulb. With a bulb from the car main light you would get very good light, but not for a long time, since it was 50 W lamp and that would give 2-3 evenings of light with a standard car battery. It was ok for the beginning of power restrictions when there was no power for a few days. If you had a good charger you could recharge the battery in a few hours and it would do the job. But as it was getting worse and there was no power for a week, the main light bulb was not an option anymore, so the tail light bulb was more appropriate. It was 10 W, and it could last on a single charge for a week or more. It was a time of saving, and energy was the currency.
Then came the best, most practical and greatest piece of technology of the ’90s – 12 V Neon tube driver, or 12 V CCFL inverter. It would make a standard neon tube shine on a 12 V with acceptable power consumption. Usually, it would drive 10 – 20 W tube, and it would produce much more light for the same amount of current than an ordinary filament bulb. Another great thing was that the neon tube did not need to be in normal working condition. The ones that did not work on normal 220 V surrounding due to the broken filament, would work like a charm on this type of device. It was because of the different way of electrical gas discharge. Now you could create a decent amount of light for a current consumption around 1 A. There were many variations and sizes of these CCFL inverters, The smallest I made worked on 6 V and took 200 mA to drive a small 10 cm neon tube. It was great for the bathroom! I also made some big ones that drove 1,7-meter tubes at their full intensity. Big ones consumed up to 1.5 A but could produce enough light for a very big room or even a cafe bar.
Most of the necessary parts could be salvaged from the old BW TVs. Remember, it was wartime and it was not possible to go to Radio Shack and by components. Transistor and ferrite were the most crucial parts and both could be found inside a TV, and suddenly it was a great thing to have one that you did not throw away. Regarding ferrite, I experimented with stick shape, U shape, even pot shape. All worked, but the best was the U shape.
Two of the U shapes were in high voltage cascade of the BW TV. I remember that we stripped CuL wire by unwinding old transformers. Capacitors and resistors could be scavenged by disassembling all sorts of electronic waste. Of course, there was improvisation also, the right values were often created by combining multiple elements in series and parallel. You had to put all your ingenuity to work :). The casings could be made out of anything, from food cans to a wooden box.
Device creation could be a piece of cake. Only the transformer took time due to the big amount of windings in the secondary coil. And like always there is a “but” at the end. Soldering iron did not work without electricity either. There were some that could work at 12 V but there was not even enough power for the light so soldering iron had to consume something else to get hot. My father is ingenious as he is used one big old soldering iron in a very specific way. He would put its tip in a fire (we all ready had a wood cooker in our living room) to get it hot enough for soldering, then clean tip a little bit and use it to solder a few wires or joints. Then back to fire again for heating up. That way he was able to create, repair and fix many devices even without electricity.
I wanted to create one for the means of this article, but I made or helped in the creation of so many of them as a kid that I almost puked even on the idea of winding a transformer again.
There is a great passion for electronics in my heart and joy of creating things, but that “survival mode” was a little too much. I think that we created more battery chargers, and CFF drivers than the small factory would do in a year. We traded them for food, wood, money, whatever possible. There is no such misery as the one in a city in times of crisis. When you live in the countryside and have some land, you can at least produce some food. Grow some vegetables and have some animals. On the asphalt and concrete in your 50 square meters, you can`t do anything but starve.
In a time like that even listening to radio would help, and I was trying to find a way to power it.
I tried to create a little generator that would use water flowing from the faucet, but my great idea turned up not to be so great when finally it came to me that someone has to pay for that water also. I was so occupied with that project that I overlooked that fact. So, it was back to the drawing board again.
The next “great” idea came to me one time when the phone ringed in the dark. Yes, we had a phone, and it worked most of the time. I still wonder why, but phones worked. They let us use the phones, although you could call only the territory controlled by “ours”. Anyway, I asked my father, how the phone works, when there is no power almost anywhere, and he explained to me that in telecom, they had very big batteries, and generators, so their equipment is always powered up. I measured the voltage on the phone line and it was 9 Volts. The situation was promising! I figured out that I could drain up to 15 mA and the telephone would still work. Great, I had a little radio that worked on 4,5 volts, found 3 AA NiCd accus, connected them in series and idea was to charge them from the phone line, and to let radio work taking power from them. That little radio could work with 10 mA current if it was on very low volume. 25 mA if it was decent volume. And I got to charge accus 24/7 so it would give me buffer to listen to the radio for let`s say 14 hours. Great, it would do the job. One time I was holding phone line wires in my hand and something very unpleasant happened. Somebody called us! It means that some 90 Volts or something like that ended up between my fingers. It was really a nasty feeling, and I threw everything away for a day or so, pissed off for what happened. Those days, the phone would ring once a week or something like that, and it had to happen while I had stripped wires in my hands! Murphy’s law! That is when I learned how telephone works, and rings 🙂 . Anyway, I ended up with that high voltage problem, and I think I used some Zener diodes and resistors to overcome it, but I can`t remember the details anymore. I used my great achievement for a while and enjoyed the radio until parents started wondering why no one is calling us ever. The phone worked, and you could call, but it just did not ring. I knew it was my “genius” device and immediately went to guerilla mode. I would connect a device during the night to recharge my batteries for a little bit, and disconnect it in the morning. This worked, and although I had to make some compromise, I actually had a few hours of music every day. A little bit of happiness in dark times. You know that special feeling when something is taken away from you by force and you finally get a piece of it back. That was it.
One more tech trick for wartime. If you live in a building without warm water, and without a water heater, you can use the washing machine to heat up some water for you. Here is my father`s genius solution:
Do not put any laundry in the machine.
Do not put any detergent or softener in the machine.
Take the drain hose and put it in your tub.
Set machine for the highest possible temperature program.
When it spins up and gets the water out, you will get much hot and clean water, just add some cold, and there is your bath, great huh?
Once every 45 days we would get those 3 hours of power, so it was a hurry to do what can be done, recharge some batteries, and of course, enjoy almost a real bath 🙂 .
It was obvious that you can`t have a battery big enough to provide you with enough Amps to last you 45 days even just for a light.
This battery pack was a lifesaver and I must dedicate a few sentences about it.
This was 10 NiCd cells pack for the RT-20 military mobile radio unit. There is a great site about them at this link. So this battery pack was 12 V, 7 Ah and it was small enough to carry. Father worked at the local radio station as a broadcast equipment specialist and since they had a diesel generator working 24/7 he would take the battery to work with him, recharge it there and then bring it back home again. Sounds crazy from today`s point of view right? Well, this worked, and we had a light problem solved. This was 4-5 Kg, 15 x 35 cm package, so it was not so hard to carry it around. I must say that these were the most durable, rechargeable batteries I ever encountered. They were made for the military by factory “Krusik” in Valjevo, Serbia. Indeed they were a military-grade technology.
There were a few more helpful things in the DIY department.
Alcohol stove made of a can was great for cooking coffee and tea, and even boiling some eggs. Soon there was no coffee and no alcohol for the stove. So it did not last much 🙂 .
The DIY candle was another useful thing to create. You put some oil in a glass and use a piece of cotton as a wick. Wick would go through a bung and piece of metal over it so bung does not burn. Great DIY candle, but it smells bad as it burns.
I don`t know precisely why, but there is some special connection between wartime and chicken eggs. Sounds crazy? Well as soon as the city was without electricity egg market expanded rapidly. Why? I suppose it was because they are cheap and easy to transport, and do not require much energy to prepare. You could boil an egg even over a candle. It means you would not starve. Eggs were being sold in front of the already closed stores, on the sidewalks, on improvised market places, literally anywhere. I ate so many eggs in those years that I can not look a chicken in the eyes anymore :). So if you ever notice that eggs are selling rapidly around you, it`s time to run away. Try to leave your country and do not look back. War is coming, or it already came. And if you want to be a normal person ever again, then it is not a surrounding for you to be in, or you may end up writing articles like this 🙂 .
We also had our own currency, and it was something to tell about. What better way to enslave citizens than to take control of the money. How to do it? Invent your own currency and print it yourself. That way you control how much money is out there, and how much does it actually worth. That is also a great way to exchange worthless paper for stable foreign currencies that you will need when you take everything you can and leave the country for some far-away place without an extradition treaty. All that you can do if you are a government or in our case a few man show. Another great thing was inflation. If by any case you would get some money you would need to run to buy something for it or change it to foreign currency asap. Why? Literally, overnight, you would need one more zero for it to be as worth as yesterday.
For example today 1 DM (Deutsche Mark, most popular currency of the time) would be exchanged for 5000 Dinars (Our new patriotic money was called “Dinar”), but tomorrow one Mark would be 50000 dinars. I remember that one time my mother got her monthly salary in those dinars and she could buy a box of matches for it. At that time she at least still had a job. It was real-life Monopoly money, or as Dire Straits would say Money for nothing. Unfortunately, the technology could not help here, but at least we used it to stay in a connection with the rest of the normal world.
I started writing this article in the hope to evoke some old memories regarding my early electronic projects. I also shared some stone-age ideas and memories. Necessity created them, nothing big, great or revolutionary. They made life a little bit easier. Now I`m thinking what would I give at that time for one of today’s led`s? Well, time was different and darkens did not come from the lack of technology but the lack of sanity and humanity. And if you notice that eggs are being sold everywhere, and whenever you see a bill, you begin thinking about Dire Straits, it may be a time to found yourself a new country, because yours may be coming into a war.
Once again thank you for reading.