books can't really compete as references anymore, I don't think. The advantage of a book is that it's easier to sit down and read a book cover to cover than to figure out what you need to look up in order to get an overview of a technology.
hah. being familiar with linux, and not so familiar with Windows, I had the opposite problem. Xen networking is... Linux networking. (the big problem is that the Dom0 kernel is crusty and ancient; something that should be remedied with Xen 4, which should be out Real Soon Now.)
Personally, I don't think that is an issue
on
The Book of Xen
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· Score: 1
if you pay for power, replacing 8 P4s with 1 dual quad-core xeon or opteron usually saves you enough in power costs to pay for the capital cost in a few months.
For me, the big differentiator is robustness and reliability. KVM will get there, I'm sure. But in the hosting space, Xen is the established tool, and KVM is the new technology. Nearly all the linux developers are rooting hard for KVM, which may mean that it will become better. Personally, I'm hedging my bets by learning both. But for now, at least, I think Xen is the best choice for the hosting provider.
If you want to run a single physical computer with multiple operating system instances, such as replacing a bank of servers with a single machine, Xen is your guy. If you want to run VMs under Linux, KVM is your friend.
That statement is just, well, daft. You're implying that Xen can't run VMs under Linux but KVM can, or Xen can run VMs on systems other than Linux or something that KVM can't do? They're both Linux only at this point, and Xen effectively runs a forked version of Linux because it isn't, and won't be, upstream.
Xen and KVM can do similar things, yes, however, last time I evaluated it (which was about a year ago, and things are changing fast) KVM was wholly unsuitable for production use. The stability and performance had a long way to go before it came anywhere near Xen.
On the other hand, KVM is much easier if what you really need is an accelerated qemu to test something real quick. setting up Xen on the desktop is a huge pain in the ass.
From a service provider perspective, all the parts of xen that need to be upstream are upstream. Guest support has been upstream for some time now. I'm fine running a funny Linux kernel (or a funny NetBSD or OpenSolaris kernel) in the dom0.
we've got a chaper on running OpenSolaris and NetBSD Dom0s in the book. We got our first taste of Xen, in fact, on NetBSD before moving to Linux Dom0s (we're talking about moving back, now that NetBSD 5 is out with x86_64 and i386PAE support)
We felt that Persig puns had been done.
on
The Book of Xen
·
· Score: 1
not that I have anything against Persig, but xen/zen puns are pretty worn out. We had a bit of a scare when we noticed that the proof for the rear cover said "Xen and the art of virtualization" - I mean, Our "no persig puns" rule aside, that's what the Cambridge folks called one of the first papers on Xen, so there would have been copyright issues. No starch caught the mistake before it hit paper, though.
for a long time... it was a little keychain dongle... you push a sequence on the buttons on front and it lets you see the passwords. There are not that many buttons, so if it's stolen don't expect it to last more than a few days, but it'll slow 'em down hopefully long enough to let you change your passwords.
if you are using a browser that is commonly compromised by opening the incorrect webpage, you are a moron. Don't run IE, don't run flash, and run noscript, and you should be fine.
restore from a known good backup whenever the root account is compromised, be it compromised by a worm or a human, in part because it's impossible to tell the difference between a human pretending to be a worm and a worm, so it is quite difficult (perhaps impossible) to know what the attacker did, and how to undo the damage.
1. the money is pretty good, at least for us UNIX janitors. six figures for a guy who never shows up before 11 and barely made it through highschool (that's me) is hard to beat in most fields. (of course, this is Silicon Valley; you're taking a 30% paycut if you are inland.) I don't know of anything outside sales where being self taught (and obviously good) carries as much respect as it does in IT.
2. standards for dress and social skills are low. My uniform consists of a company T shirt (not the same shirt... I have 7 of them, really!) worn jeans, and heavy boots with a heel grounder. I shave once a month and cut my hair less often. People are okay with me saying things like "the vendor is trying to lock you in so they can screw you" (my favorite luke quote is "If you single-source anything, the company you our buying from has a fiduciary duty to their shareholders to screw you.)
3. the white guy bonus (By which I mean, the premium you get for being on site, and a native speaker of the language. It has more to do with accent and the patience to understand accents than anything else.) is giant. When the boss was born in the Philippians and half the tech staff was born in India or China, being willing to say "what?" and repeating back what people have said so that you actually know what the hell is going on means that you can become massively more valuable than average by just being slightly less racist and taking a few minutes to understand what someone is trying to say. Really, dealing with an accent is much less difficult than dealing with a non-technical, in my mind. Besides the funny talking foreigners make lunch time much more interesting. Like the song says, we're all a little bit racist, but if you can keep it in your pants while you are at work, you are ahead of the game. Most people can't.
4. there is room for both gristled experts who have been doing the same thing since the 70s, and neophiles who get bored after three years. Some things are always changing but some things are the same. (I know guys who have been using UNIX like operating systems longer than I have been drawing breath. Their skills are still relevant.)
Personally, I believe *NIX skills to be much more durable, time-wise, than Microsoft skills, simply because you can follow it down to what is actually happening (something that I believe is difficult to do on a windows system.) and while the interfaces change fairly rapidly both in *NIX and Windows, what the system actually does changes very slowly.
5. Outsourcing is more difficult than you think. One place was trying to outsource all their IT. they were trying the first time I worked for them; I left for greener pastures a year later. A year later, I came back and worked for this company again. It wasn't until I had been working for another year before they got an outsourcing firm that was worth anything at all.
you are really into it. You are competing with people who are essentially willing to do it for free, either because we are that into it, or because we lack the interpersonal skills to do anything else (sometimes, a little of both)
That said, it sounds like you have a bigger problem with your bosses than with the IT field. there are places in IT that have good bosses, and it makes all the difference in the world. When I was a youngster, I got a bad boss once, and I, too decided I was leaving IT. I took a month off and a road trip to decide what I wanted to do, but when I was done with that, I got another IT job, one with a decent manager.
Personally, I dislike headhunters, but I've used them in the past when I was desperate. They are a good way to get corporate work (usually with mediocre pay and low expectations. However, they take a large chunk of the pay, and usually end up making it much harder for you to get paid in a timely manner, if they operate as a body shop.
As far as I can tell, the only way to get body shops to pay you on time, assuming you are using corp-to-corp billing rather than 1099 or W2, is to tell the client you won't be showing up if the payment is late, and then to follow through and take a few days off.
Still, headhunters and body shops have access to a lot of jobs that most of us don't, so if you are desperate or useless, they can be quite helpful.
I don't remember the last time I worked on a team with more than five people who were all US born. "Nativisim" and Xenophobia make you dramatically less useful if you are hiring or working with skilled workers. If you need the best in the world, sometimes you have to look outside your back yard.
Usually you find this racism and xenophobia amongst the lower classes. Sure, if you are hiring for a job making burgers, where one guy is about as good as the next you can hire a bunch of guys who talk like you and do fine. But if you are hiring skilled workers, and you turn away people who come from a different background, you will get your lunch eaten. Your competition? they will hire the best people they can get, and eat your lunch.
Finding people who know how to properly use oracle is a real bear. Sure, you can hire people with oracle experience, but most of them were the 'corporate DBA' types who don't know how to do anything out side of the script. I can't tell you how many clients I've seen struggling with their oracle installs; either because the system does not perform as promised, or because the 'cluster' needs to be rebooted every time one node crashes in an unexpected manner.
Now, I'm just the Linux janitor, not a DBA, but when I see those problems on MySQL or PostgreSQL, I can fix them. I've replaced more than one MSSQL database with a MySQL setup, and often see orders of magnitude speed increases that I suspect are due to misconfiguration of the proprietary database. The open-source stuff is just plain easier to use, at least for Linux janitors like me, and has better support.
I'm sure Oracle and MSSQL are both fine databases if you know how to use it and you configure it correctly; I'm just saying that paying a lot of money doesn't relieve you from needing to know those things. You still need to pay for a technician who actually understands it. The advantage of the free (as in freedom) products is that there are a whole lot more people with real (that is, non-scripted, where you need to do something new or are expected to solve a problem beyond 'reboot and apply the redo logs') experience with the free databases than with multi-million dollar oracle installs, and that sometimes your expensive support people just shrug and say 'I don't know. why don't you upgrade your linux kernel.'
Sticking with the free stuff, using a search engine such as google gets you pretty good support for commonly used free software. Often better support than what you get when you pay lots of money for support.
and I don't seem to have trouble achieving uptime north of a year. (I did a hardware refresh around the year mark, though, so I don't have much anything that has been up longer)
But to answer the question, yes, people want the best service, even if you tell them up front that your service has made some tradeoffs to keep prices down.
If anything, I think my customers, especially the new ones, are quicker to leave than they would be on a more expensive service; they are suspicious. I've lost more than one this week due to a 48 hour backlog provisioning new accounts.
you can't use reliable shared storage at my pricepoint. Shared storage is required for live migration.
on the other hand, xen does let me 'xm save' then 'xm restore' after a reboot, so when I reboot the dom0, the DomUs just go offline for about 10 minutes. (the reboot takes a long time 'cause of the save/restore process)
exclusions were funny. I mean, if I co-lo at a place that doesn't have redundant power, and the power outage takes you down, that is my responsability. Same if my upstream goes down; Only running through one upstream would be a complete dereliction of duty on my part.
but then, I always thought negotiation was a little funny, too; I mean, I can provide you service at a significantly lower price if I can provide you the exact service I'm providing to everyone else. I mean, I appreciate feedback; but negotiating with every customer seems funny. I'm giving the best deal to the customer who spends the most of my time at the expense of the silent majority who don't complain and pay on time? that seems backwards.
on the 'not our fault' issue, a SLA should really substitute 'I can't be expected to do anything about it, or to have prevented it' - sure if my immediate upstreams fail, I need to do something about it. same goes for power. But if the customer's dsl goes out, or some fishing trawler cuts the last trans-adlantic cable coming into your country, well, that's not really something I should be expected to fix. but that's hard to define precisely.
outages from the uptime calculation? I thought only really shady companies; the type that put up the 'site is down for maintenance' page when something breaks, excluded planned downtime from the sla. I don't exclude planned downtime from my SLA http://book.xen.prgmr.com/mediawiki/index.php/SLA - in fact, the last time I paid out a SLA the downtime was planned; I was moving some servers from one rack to another.
I just can't imagine the phone company saying "oh, yeah. the phone outage was planned, so we still have 100% uptime"
you seriously think I can tell my customers that they will get rebooted next week and expect them to be OK with that? Sure, if you are running windows, your users are used to it, but I know for me, a reboot is a reboot is a reboot; and usually it is followed by a number of customers leaving. It's not just the downtime; many customers (I provide VPSs) configure services by hand, which means that when it comes back up, it's wrong.
That said, it will be a long time before I use Ksplice on the Dom0, just 'cause a planned reboot, while bad, is still much better than an unclean shutdown. I tend to be very conservative on those boxes.
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Was recommended to me by someone I respect quite a lot, someone who isn't known for being 'fuzzy headed'
But yeah, I read the book and I didn't get it, either.
books can't really compete as references anymore, I don't think. The advantage of a book is that it's easier to sit down and read a book cover to cover than to figure out what you need to look up in order to get an overview of a technology.
hah. being familiar with linux, and not so familiar with Windows, I had the opposite problem. Xen networking is... Linux networking. (the big problem is that the Dom0 kernel is crusty and ancient; something that should be remedied with Xen 4, which should be out Real Soon Now.)
if you pay for power, replacing 8 P4s with 1 dual quad-core xeon or opteron usually saves you enough in power costs to pay for the capital cost in a few months.
For me, the big differentiator is robustness and reliability. KVM will get there, I'm sure. But in the hosting space, Xen is the established tool, and KVM is the new technology. Nearly all the linux developers are rooting hard for KVM, which may mean that it will become better. Personally, I'm hedging my bets by learning both. But for now, at least, I think Xen is the best choice for the hosting provider.
I'm pretty sure I've emailed you to ask dumb questions several times, and you answered. :)
If you want to run a single physical computer with multiple operating system instances, such as replacing a bank of servers with a single machine, Xen is your guy. If you want to run VMs under Linux, KVM is your friend.
That statement is just, well, daft. You're implying that Xen can't run VMs under Linux but KVM can, or Xen can run VMs on systems other than Linux or something that KVM can't do? They're both Linux only at this point, and Xen effectively runs a forked version of Linux because it isn't, and won't be, upstream.
Xen and KVM can do similar things, yes, however, last time I evaluated it (which was about a year ago, and things are changing fast) KVM was wholly unsuitable for production use. The stability and performance had a long way to go before it came anywhere near Xen.
On the other hand, KVM is much easier if what you really need is an accelerated qemu to test something real quick. setting up Xen on the desktop is a huge pain in the ass.
From a service provider perspective, all the parts of xen that need to be upstream are upstream. Guest support has been upstream for some time now. I'm fine running a funny Linux kernel (or a funny NetBSD or OpenSolaris kernel) in the dom0.
"The hypervisor is linux" is the idea behind KVM. The Xen hypervisor is most certainly not Linux.
we've got a chaper on running OpenSolaris and NetBSD Dom0s in the book. We got our first taste of Xen, in fact, on NetBSD before moving to Linux Dom0s (we're talking about moving back, now that NetBSD 5 is out with x86_64 and i386PAE support)
not that I have anything against Persig, but xen/zen puns are pretty worn out. We had a bit of a scare when we noticed that the proof for the rear cover said "Xen and the art of virtualization" - I mean, Our "no persig puns" rule aside, that's what the Cambridge folks called one of the first papers on Xen, so there would have been copyright issues. No starch caught the mistake before it hit paper, though.
for a long time... it was a little keychain dongle... you push a sequence on the buttons on front and it lets you see the passwords. There are not that many buttons, so if it's stolen don't expect it to last more than a few days, but it'll slow 'em down hopefully long enough to let you change your passwords.
but mine broke :(
if you are using a browser that is commonly compromised by opening the incorrect webpage, you are a moron. Don't run IE, don't run flash, and run noscript, and you should be fine.
Exactly what I meant. firefox on linux noscript and without flash is fairly safe
computer, my browser is completely broken.
restore from a known good backup whenever the root account is compromised, be it compromised by a worm or a human, in part because it's impossible to tell the difference between a human pretending to be a worm and a worm, so it is quite difficult (perhaps impossible) to know what the attacker did, and how to undo the damage.
1. the money is pretty good, at least for us UNIX janitors. six figures for a guy who never shows up before 11 and barely made it through highschool (that's me) is hard to beat in most fields. (of course, this is Silicon Valley; you're taking a 30% paycut if you are inland.) I don't know of anything outside sales where being self taught (and obviously good) carries as much respect as it does in IT.
2. standards for dress and social skills are low. My uniform consists of a company T shirt (not the same shirt... I have 7 of them, really!) worn jeans, and heavy boots with a heel grounder. I shave once a month and cut my hair less often. People are okay with me saying things like "the vendor is trying to lock you in so they can screw you" (my favorite luke quote is "If you single-source anything, the company you our buying from has a fiduciary duty to their shareholders to screw you.)
3. the white guy bonus (By which I mean, the premium you get for being on site, and a native speaker of the language. It has more to do with accent and the patience to understand accents than anything else.) is giant. When the boss was born in the Philippians and half the tech staff was born in India or China, being willing to say "what?" and repeating back what people have said so that you actually know what the hell is going on means that you can become massively more valuable than average by just being slightly less racist and taking a few minutes to understand what someone is trying to say. Really, dealing with an accent is much less difficult than dealing with a non-technical, in my mind. Besides the funny talking foreigners make lunch time much more interesting. Like the song says, we're all a little bit racist, but if you can keep it in your pants while you are at work, you are ahead of the game. Most people can't.
4. there is room for both gristled experts who have been doing the same thing since the 70s, and neophiles who get bored after three years. Some things are always changing but some things are the same. (I know guys who have been using UNIX like operating systems longer than I have been drawing breath. Their skills are still relevant.)
Personally, I believe *NIX skills to be much more durable, time-wise, than Microsoft skills, simply because you can follow it down to what is actually happening (something that I believe is difficult to do on a windows system.) and while the interfaces change fairly rapidly both in *NIX and Windows, what the system actually does changes very slowly.
5. Outsourcing is more difficult than you think. One place was trying to outsource all their IT. they were trying the first time I worked for them; I left for greener pastures a year later. A year later, I came back and worked for this company again. It wasn't until I had been working for another year before they got an outsourcing firm that was worth anything at all.
you are really into it. You are competing with people who are essentially willing to do it for free, either because we are that into it, or because we lack the interpersonal skills to do anything else (sometimes, a little of both)
That said, it sounds like you have a bigger problem with your bosses than with the IT field. there are places in IT that have good bosses, and it makes all the difference in the world. When I was a youngster, I got a bad boss once, and I, too decided I was leaving IT. I took a month off and a road trip to decide what I wanted to do, but when I was done with that, I got another IT job, one with a decent manager.
Personally, I dislike headhunters, but I've used them in the past when I was desperate. They are a good way to get corporate work (usually with mediocre pay and low expectations. However, they take a large chunk of the pay, and usually end up making it much harder for you to get paid in a timely manner, if they operate as a body shop.
As far as I can tell, the only way to get body shops to pay you on time, assuming you are using corp-to-corp billing rather than 1099 or W2, is to tell the client you won't be showing up if the payment is late, and then to follow through and take a few days off.
Still, headhunters and body shops have access to a lot of jobs that most of us don't, so if you are desperate or useless, they can be quite helpful.
I don't remember the last time I worked on a team with more than five people who were all US born. "Nativisim" and Xenophobia make you dramatically less useful if you are hiring or working with skilled workers. If you need the best in the world, sometimes you have to look outside your back yard.
Usually you find this racism and xenophobia amongst the lower classes. Sure, if you are hiring for a job making burgers, where one guy is about as good as the next you can hire a bunch of guys who talk like you and do fine. But if you are hiring skilled workers, and you turn away people who come from a different background, you will get your lunch eaten. Your competition? they will hire the best people they can get, and eat your lunch.
Finding people who know how to properly use oracle is a real bear. Sure, you can hire people with oracle experience, but most of them were the 'corporate DBA' types who don't know how to do anything out side of the script. I can't tell you how many clients I've seen struggling with their oracle installs; either because the system does not perform as promised, or because the 'cluster' needs to be rebooted every time one node crashes in an unexpected manner.
Now, I'm just the Linux janitor, not a DBA, but when I see those problems on MySQL or PostgreSQL, I can fix them. I've replaced more than one MSSQL database with a MySQL setup, and often see orders of magnitude speed increases that I suspect are due to misconfiguration of the proprietary database. The open-source stuff is just plain easier to use, at least for Linux janitors like me, and has better support.
I'm sure Oracle and MSSQL are both fine databases if you know how to use it and you configure it correctly; I'm just saying that paying a lot of money doesn't relieve you from needing to know those things. You still need to pay for a technician who actually understands it. The advantage of the free (as in freedom) products is that there are a whole lot more people with real (that is, non-scripted, where you need to do something new or are expected to solve a problem beyond 'reboot and apply the redo logs') experience with the free databases than with multi-million dollar oracle installs, and that sometimes your expensive support people just shrug and say 'I don't know. why don't you upgrade your linux kernel.'
Sticking with the free stuff, using a search engine such as google gets you pretty good support for commonly used free software. Often better support than what you get when you pay lots of money for support.
and I don't seem to have trouble achieving uptime north of a year. (I did a hardware refresh around the year mark, though, so I don't have much anything that has been up longer)
But to answer the question, yes, people want the best service, even if you tell them up front that your service has made some tradeoffs to keep prices down.
If anything, I think my customers, especially the new ones, are quicker to leave than they would be on a more expensive service; they are suspicious. I've lost more than one this week due to a 48 hour backlog provisioning new accounts.
you can't use reliable shared storage at my pricepoint. Shared storage is required for live migration.
on the other hand, xen does let me 'xm save' then 'xm restore' after a reboot, so when I reboot the dom0, the DomUs just go offline for about 10 minutes. (the reboot takes a long time 'cause of the save/restore process)
exclusions were funny. I mean, if I co-lo at a place that doesn't have redundant power, and the power outage takes you down, that is my responsability. Same if my upstream goes down; Only running through one upstream would be a complete dereliction of duty on my part.
but then, I always thought negotiation was a little funny, too; I mean, I can provide you service at a significantly lower price if I can provide you the exact service I'm providing to everyone else. I mean, I appreciate feedback; but negotiating with every customer seems funny. I'm giving the best deal to the customer who spends the most of my time at the expense of the silent majority who don't complain and pay on time? that seems backwards.
on the 'not our fault' issue, a SLA should really substitute 'I can't be expected to do anything about it, or to have prevented it' - sure if my immediate upstreams fail, I need to do something about it. same goes for power. But if the customer's dsl goes out, or some fishing trawler cuts the last trans-adlantic cable coming into your country, well, that's not really something I should be expected to fix. but that's hard to define precisely.
does just about the same thing.
outages from the uptime calculation? I thought only really shady companies; the type that put up the 'site is down for maintenance' page when something breaks, excluded planned downtime from the sla. I don't exclude planned downtime from my SLA http://book.xen.prgmr.com/mediawiki/index.php/SLA - in fact, the last time I paid out a SLA the downtime was planned; I was moving some servers from one rack to another.
I just can't imagine the phone company saying "oh, yeah. the phone outage was planned, so we still have 100% uptime"
you seriously think I can tell my customers that they will get rebooted next week and expect them to be OK with that? Sure, if you are running windows, your users are used to it, but I know for me, a reboot is a reboot is a reboot; and usually it is followed by a number of customers leaving. It's not just the downtime; many customers (I provide VPSs) configure services by hand, which means that when it comes back up, it's wrong.
That said, it will be a long time before I use Ksplice on the Dom0, just 'cause a planned reboot, while bad, is still much better than an unclean shutdown. I tend to be very conservative on those boxes.