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UML runs on the host server in userspace.

That means that the UML server will only have access to the host to the extent of that program's access.

You can do things like running the UML instance chrooted. Running it as an unpriviledged user. Disabling the 'hostfs' UML kernel option (which gives the UML access to files on the host).

You can also disable module loading in the UML kernel. That will prevent the user 'injecting' code into the UML process.

So... provided you set it up right, the UML instances should be pretty much isolated and secure. At least as any Linux process is capable of being isolated and secure ;)

- P
RimuHosting - Linux VPS Hosting

I haven't worked with a Z/Linux VM before. However, I have used User Mode Linux to create a dozen or so virtual servers per host server. And I'd imagine that the benefits offered by UML would also apply to Z/Linux VMs.

For example, with UML you're able to get much better resource utilisation. e.g. most of the time the machine is idle. When one of the UML servers need the host server's resources, they're there (CPU, network, disk IO, etc). That means you can have multiple UML servers bursting up to the performance potential of the host server. Certainly a better resource utilisation than having several host servers running mostly idle.

Another benefit of virtual machines are their logical separation from the host server. Each virtual server has their own users (including root), applications, file systems, IP address, etc. That means that if security is compromised on one, the others are unaffected. Ditto resources can be allocated to each virtual server according to need. And any mis-configuration on one doesn't affect the other. This compares to running multiple applications on the same server for different purposes (e.g. running HR and Account systems on one server, if email goes down them both systems are affected. In a virtual server setup, only one of the other would be affected.

So... Thumbs up to server virtualization software in general. Particular kudos to UML. And good luck finding out about Z/Linux!

- P
RimuHosting.com - Linux VPS Hosting

JBoss let's you run JSP pages and servlets. Of course, Tomcat and Jetty offer that as well.

JBoss offers things like EJB, JMS, JNDI, transaction management, clustering, container managed persistence and DB connection pooling.

Whether you need those things or not, is another question. Whether you use those things to create model-view-controller designs is also another question. You can write an J2EE app and it can still rank up there with the worst code designs in history.

One quite cool things about J2EE (and servlets) is the ability to create web application files (.war or .ear). You just assemble this file then pop it on the server. Voila. No further configuration required. It just works.

Another reason a lot of people use JBoss is because it (or rather, J2EE) looks really good on your resume. You can become buzzword compliant by simply downloading the app and having a quick play on a Sunday after noon. Ooops, got to kick that facetiousness habit.

Anyway, I'm glad that the JBoss group thinks it's worth shelling out $100K pa on certification. Provided they get their payback from the corporates that want the certification, not us regular joes that just like JBoss because it works.

- RimuGuy
JBoss Hosting on Linux VPSs

I used to stress about Java performance. I'm not sure it was ever warranted. Certainly, things are plenty fast enough now.

Not only have the JVMs improved - e.g. hotspot - but the servers and PCs I'm using now are 3 times faster (2.4Ghz vs. 800Mhz a few years back).

What I think they need to concentrate on now, is getting the memory usage back down. 100MB to run an eclipse IDE is just too fat. And it's hard being a JSP Host when each Servlet engine chews up 60MB of memory on my host servers.

FWIW, the 1.5 release sounds like memory will get a good looking at. Let's hope so.

So the 'pattern' is that the RIAA is targetting a random selection of music? Ummm.

And, moreover, it looks like they're targetting users with popular songs (e.g. Sk8ter boi). Like, umm, people are offending in proportion to how popular a song is and not downloading things they don't like.

The obvious exception being the people that downloaded Ms. Houston's songs in an obvious attempt to thwart the RIAAs 'selection criteria'. Boy, imagine the humiliation. At a job interview, admitting you served time for listening to 'How will I know?'. You'll never work again.

- Peter
Linux VPS Hosting. Come on someone wants to try hosting with a 2.6 kernel...

If you want to try out the new 2.6 kernel, I'd suggest you do it with User Mode Linux. You can load it up on your PC without having to change the host kernel and play around with all the cool 2.6 features.

Note: use the UML patch from the author, Jeff Dike, vs. what is in the kernel.org source which is old and crufty. Jeff's patches are much more up to date and more widely used.

BTW: if anyone out there wants to try out their hosting on a 2.6 kernel (just to see how it goes, or as part of a 2.6 testing program), then I'm making a 2.6 kernel option available on my UML hosted Virtual Private Servers.

From the article it seems that 'most' people remembered the password the next day. What about a couple of month later after not using it? Oh, and:

Write down exactly what you saw under each blot. You don't have to tell anyone. It'll be your secret.

Umm...

Sounds to me like, if you're going to write it down, you may as use a password encrypted private key file and then pop your public key into all the servers to which you need access.

Heck, using SSH and public/private keys you can use a 1024 bit key, have secure access to hundreds of systems, and only have to enter your password once per bootup.

- Peter
RimuHosting - UML VPS Hosting

One of the new things in the kernel is User Mode Linux. And I run a hosting company that runs UML servers. So this release is a very cool milestone.

Sadly, the 'official' tree is not keeping up with Jeff Dikes patches. Which after being initially accepted are now gathering dust in some bitkeeper dump.

This from Jeff on the UML mailing list:

Linus hasn't been taking them [the UML Patches], so until he changes that, there's not a lot I can do.

My current thinking is that either I will launder them to Linus through akpm [Andrew Morton] during the runup to 2.6, or have him apply them directly after 2.6.0.

Hopefully, Jeff will get his patches compiling against the latest 2.6 kernel and Linus or Andrew will accept them. This is a cool piece of technology. And what's currently in the 'official' kernel has become old and crufty. (Workaround being to apply Jeff's patches).

Anyway, I got around to downloading and compiling the latest 2.5 kernel with the UML patches and running up a few root file systems. It seems to work well. Er, I mean, boot up without panicing.

If anyone is interested in tinkering with a Linux server running the 2.5 kernel, feel free to contact me. It'd beat having a malicious alpha kernel corrupting all the data on your PC.

- Peter
RimuHosting - VPS Servers. Now with 2.6 Kernels

For anyone interested in having a tinkering/testing Linux server

I host a bunch of VPSs based on Jeff Dike's UML (User Mode Linux) project.

One (of the many) cool things UML allows is for you to try out new kernels without having to dedicate a real box to it. Even if you're only dedicating the box to it between kernel swap reboots. Especially if you're not sure if the new kernel will corrupt your precious partitions.

The UML 'host' server can continue to run whatever stable 2.4 kernel you need (in my case 2.4.21).

You SSH from your 'host' server into your hosted UML kernel. Play around, test reliability, fiddle with new features, regression test your apps.

So anyway, I'm off to grab the new kernel and have a play. Maybe even see if there are any crazies out there who want hosting with the 2.5/2.6-pre kernel.

- Peter
RimuHosting - Linux VPS Hosting

I'd second JBoss for clustering. The middle tier, EJBs and the like 'just works'.

The front end is tricker: e.g. setting up DNS round robin + virutal IP takeover in case a front end server goes down.

And the back end (database) is also fun. e.g. setting up a distributed file system. Or setting up database replication. Both doable, but hard to do right and get great performance.

I had one customer use our VPS servers to help them get clustering going.

They can set up several virtual servers (with their own file systems and IP addresses, etc) all on one physical server.

Once they have nailed they setup, they can them deploy on separate physical servers. Its a lot quicker, easier to manage (and cheaper) doing it that way.

JBoss has been garnering a lot of publicity lately, at least in Java circles. It has been quite the center of controvesy, in an otherwise boring world.

First there is the bust up with Sun. JBoss wanting J2EE certification and Sun be a bit difficult (basically saying they wouldn't pass).

Then there was the 'best application server' http://www.sys-con.com/java/readerschoice2003/vote .cfm 'vote rigging' issue. One year accussing Oracle of cheaping because they asked their employees to vote, and the next year JBoss does the same (asked its mailing list members to vote for JBoss).

Now of course there is this new company split off from JBoss LLC.

Still to come: will JBoss LLC removing CVS commit rights from the coredevelopers group? Will JBoss LLC go out of business?

We'll see..

In the mean time: at least people are hearing about this great product (developer tiffs aside). No such thing as bad publicity, right? Hopefully, too many people won't be scared off. Then where would all my new customers come from?

- Peter.
RimuHosting - JBoss Hosting on Linux VPS

Get a semi-dedicated server/VPS. Since those plans aren't cramming hundreds of sites on a server, they will offer more space.

e.g. my company offers a VPS plan running User Mode Linux (UML) with 4GB of space.

Some of the things you're asking for:

• PHP,
• MySQL,
• raw log files,
• FTP,
• decent bandwidth (~10 GB),
• around 300 MB disk space

Are available from almost any host. The competition out there is fierce and I wouldn't be surprised if you could get this for $12/year. But for that price I'd expect pretty hit and miss service (get two plans at different providers, copy data between and plan and keep control over your DNS if you need to switch!)

Some of the other requirements you requested will probably 'bump you up' a hosting level:

• the ability to configure my server somewhat (htpasswd, htaccess),
• crontab,
• SSH,
• POP accounts,

Most semi-decent shared plans will have those features.

Also, you may want to consider a Virtual Private Server. The host server will run several VPSs. Each VPS will get its own IP, memory and will share disk IO and bandwidth. You would get root access with the ability to install your own software, compile your own code, set up cron tabs, init tabs, etc.

There are a few companies that are offering VPS services now, including my own, Rimu Hosting. And our VPS plans start from $29/month.

Whatever you do, A good place to do some research on this is Webhostingtalk.com They have a 'requests' forum that you can post your requirements in and people will reply with offers. You can check the posters profiles and search for meantion of their outfits on the forums to guage how reliable they are. BTW: WHT is owned by Rackshack IIRC (And if you're after dedicated server hosting Rackshack is pretty decent).