Topic: Some quick Linux thoughts

I've tried to write this several times but it keeps getting too long.

Using CentOS, based heavily on RedHat Enterprise Linux 5, my general impressions are:
The LVM stuff is good. I think ZFS will be better when it's ironed out, but at present, LVM allows you to easily span disks for more disk space and grow and shrink partitions. 

The binary upgrading is good. If it was necessary to customize a config file, it's relatively simple, dealing with the source rpm, in the same way one can customize a port's makefile.  Most of the time, they choose sane defaults, and I haven't had any problems with the programs that we use.

The big downsides are the bloat--it becomes quite time consuming to go through a default install and remove things that they want to install by default, many of them GUI server configuration tools.  This is a bit surprising in a way, as RH EL is aimed at administrators, as far as I know.  Sometimes, their docs say use the GUI tools and it will be difficult to figure out how to do it by editing text files. 

The RH deployment guide is pretty good.  However, Linux docs in general are rather poor.  One starts with a man page--if that doesn't help, some programs have this Gnu thing, info pages, which are supposed to be more complete.  The problem is that it seems that Gnu folks only got around to writing 10 percent of them--the other 90 percent are these obscure or incomplete Linux man pages in a different format. 

Finding documentation can be a chore.  RH runs a bunch of what I would consider, especially on a server, unneeded services at startup.  Yet, finding docs on what each program does can be a challenge.  For instance, ConsoleKit.  No man page, no info page.  Finally, in /usr/share/doc there's a one paragraph README that doesn't give too much information.  That is perhaps the most frustrating thing. 

On CentOS, which is enterprise oriented, the binary updates work quite well.  The only downside is that sometimes, there are dependencies which escape me. Of course, this can be true for FreeBSD too--I saw someone on the X11 list asking, why is this pulling in CD record as a dependency?   

Fedora is more like running CURRENT and things break.  That can be another post.  The biggest difference though, is that these breakages often don't get officially documented as they do in the BSD's.   Perhaps that's one of the advantages of a smaller core group. 

So, biggest advantages, easy to use LVM and binary upgrades.  Biggest downsides are bloat, seemingly absurd dependencies and fragmented, often inadequate, docs. 

(The bloat seems to be in all Gnome centric distributions.  A developer friend said, "Well, with Gnome, it seems to be that he who can pull in the most dependencies, wins.)

<@andre> i would be so much more efficient if i wasn't so stupid

Re: Some quick Linux thoughts

I agree with almost everything you said scottro. The only exception is that ZFS already beats LVM. Snapshots are no use whatsoever if they cannot persist across reboots and the service integration of ZFS is miles beyond LVM. share[nfs,iscsi,cifs}=on anyone? Unfortunately as someone who works with a ton of RHEL servers and has the dubious distinction of RHCE, I know far more about RedHat's borkeditude than I ever wanted to know.

... and then they said "I bet you can't make MINIX kernel panic!!!" And that's when I got mad

Re: Some quick Linux thoughts

AHA.  I have just found a mentor.  (Said in sinister accent)  You poor fool, you should have never let me know that you were well-experienced in RH.  smile

<laughs evilly>.

(Don't  worry, KP, just kidding.   I might ask you things if I get stuck, of course, but I realize that unlike me, you have a life.)

Now that I know someone truly understands, let me give a typical example.  VirtualBox is a more or less opensource virtual machine that runs faster than qemu in my experience. 
I put it on a Fedora laptop.  I wanted to use bridging rather than their default NAT neworking.  (Similar to quemu).

In FreeBSD you leave your interface up and create a bridge.  Then the tap0 thing is added to the bridge and gets its address.

In Linux, to make a bridge, first you 0 out the NIC.  That is, I do ifconfig eth0 0.0.0.0 and then give the bridge (br0 in this case) an address. Ok, so far, so good, the machine can reach the outside world.

Now when I did this on ArchLinux, I would just choose to either have the host machine or Virtual Machine have an address, I couldn't do both.  Regardless, it was fairly easy to do, a series of commands creating tun, or tap or whatever, my memory escapes me.

In Fedora, first I have to install bridge-utils.  Then, it's still not working. The VirtualBox docs, although specifically for Fedora, neglect to mention the fact that their script, when run as normal user, can't find ifconfig.  (In Fedora, you're protected from yourself by not having /sbin and /usr/sbin/ in your path.)  I fix that and it's still not working, something with permissions.  I go back to doing it the basic way--but I have no tunctl command, used to create the tap device.  I try yum whatprovides but have no luck. 

Now, I google (which I shouldn't have to do if the VirtualBox docs were done right) and find that Lo! and Behold!  I need to install openvpn.  Well, yeah, of course, that had a lot to do with it.  Of course, we're talking about a distribution that needs a Gnome fast user switch program running to have sound on a system without gnome.  Now, THAT makes sense.

I suspect that KP laughed when I talked about RH bloat.  I'm sure he too has gone through the frustration of trying to do a minimal install and finding that this won't work without that absolutely unrelated program, even with his RHCE.  (Which, though he mocks it, isn't all that easy to do--a lot more difficult, from what I understand, than some of the other certs.)

A quick PS.  Solved by the simple expedient of installing the free VMWare-server, which works just as quickly, in my experience and gives the virtual machine a network address on your LAN out of the box.  Which brings up another plus for Linux--at present, VMWare and VirtualBox work on them without effort.  With FreeBSD, neither does, although there's now a bounty for VMWare workstation and I suspect Orlando will get it working soon.  There's also work on getting VirtualBox ported, with some success.

Still, at present, both work on Linux without too much effort. (If I could have used the VirtualBox default NAT networking, which like qemu, gives that default 10 something address, I would have been fine, but for my situations, I need the virtual machine to have its own address on the LAN.)

Last edited by scottro (2007-11-24 16:00:31)

<@andre> i would be so much more efficient if i wasn't so stupid

Re: Some quick Linux thoughts

Ouch scottro, that is some good breakage you ran into. Suprisingly enough, my last attempt at a minimal Fedora desktop ended at a LACK of packages. I was all set with fluxbox working and went to install the usual console apps I use. BitchX, mutt, esmtp, etc. Only esmtp and BitchX, along with a host of other things are no longer there. I went looking for answers and ran into the most beautiful circle of iront I'd ever seen. In Fedora 8 the got rid of extras and "merged" it with Core. Now according to their docs and propaganda this was a great thing for "user friendliness". What they neglect to mention is that any package from extras that a Fedora maintainer felt like packaging was merged into Core and any package they didn't feel like packaging was dropped. Why no, Mr. Volunteer,  you cannot continue to package that app you've been maintaining for several years and have it in a repository because extras no longer exists. Under a guise of making things better for the user, they turned on a whole group of their own users and made their contributions irrelevant.


And unrelated to that point, I still want to know why you absolutely cannot do a minimal install without the bluetooth stuff getting installed as well. I'm sure both people out there using bluetooth devices with their desktop will be thrilled.

... and then they said "I bet you can't make MINIX kernel panic!!!" And that's when I got mad

Re: Some quick Linux thoughts

You literally almost murdered me there.  I was chewing a pretzel as I read, "...both people out there using bluetooth device.." and almost choked.   Consider that line stolen next time I rant on Fedora forums.  (Off to fedoraforums to look for a chance to use the line.)

<@andre> i would be so much more efficient if i wasn't so stupid

Re: Some quick Linux thoughts

As a follow up, it turns out that it's relatively easy to get VirtualBox working with bridged networking--however, it doesn't work with wireless--that is, if I'm on the wireless card, though I can bridge, and the VM can talk to the host and vice versa, and the host can still do whatever it normally does, the VM can't reach anything outside of the host.  Odd, since even if it gets its address from the router, afterwards, it can't ping the router.  I vaguely remember that being the case in the past as well. 

However, last time I did this, VMWare server was able to work well with the wireless. I haven't found that to be the case this time.  I suspect I've simply overlooked something, but tomorrow's another day.

Linux bridging is, to my mind, a bit peculiar as there is a brief interval when you lose your network completely, which doesn't happen in FreeBSD.  Basically, you create a bridge interface, bring down the ethernet one, then add the ethernet one as a bridge member.   Then you bring up the bridge and you're back on the network, but on br0, not eth0.  With FreeBSD, I would just be using my ethernet, e.g., vr0, and the tap interface.  The bridge just sort of sat there and, errm, bridged between them. 

I suppose it could be a real pain if you were doing it remotely, but I'm sure it could be easily scripted, so that you could connect again. 

For wired networks, I think I'm going to start recommending VirtualBox (to Linux users) over VMWare server.  I saw a noticeable difference in speed.  (Seat of the pants impression, no benchmarks.)

<@andre> i would be so much more efficient if i wasn't so stupid

Re: Some quick Linux thoughts

just a quick rant on Linux because I need some empathy

Re: Some quick Linux thoughts

that's dumb. i also don't know how to list apt-get-installed packages.

Re: Some quick Linux thoughts

KernelPanicked wrote:

I agree with almost everything you said scottro. The only exception is that ZFS already beats LVM. Snapshots are no use whatsoever if they cannot persist across reboots and the service integration of ZFS is miles beyond LVM. share[nfs,iscsi,cifs}=on anyone? Unfortunately as someone who works with a ton of RHEL servers and has the dubious distinction of RHCE, I know far more about RedHat's borkeditude than I ever wanted to know.

I used to like LVM.  Especially the first time I had to add drives to the system.

Then the day came that I needed to use snapshots ... and realised I was supposed to reserve space in the volume group back when the server was setup, had to guesstimate how much space the snapshot would need over its lifetime, would have to "freeze" the source partition while the snapshot was made, and a bunch of other hoo-haw that totally defeated the purpose of snapshots.  What idiot decide to make LVM snapshots out-of-band?

Even UFS snapshots are better than LVM snapshots.  And neither compares in any way to ZFS snapshots.

Storage management on Linux is currently b0rked, in comparison to GEOM and ZFS on FreeBSD.

Re: Some quick Linux thoughts

scottro wrote:

Linux bridging is, to my mind, a bit peculiar as there is a brief interval when you lose your network completely, which doesn't happen in FreeBSD.  Basically, you create a bridge interface, bring down the ethernet one, then add the ethernet one as a bridge member.   Then you bring up the bridge and you're back on the network, but on br0, not eth0.  With FreeBSD, I would just be using my ethernet, e.g., vr0, and the tap interface.  The bridge just sort of sat there and, errm, bridged between them.

Network management of any kind is b0rked on Linux.  There are just too many different little tools that are packaged in so many different ways on each distro.  ip, tunctl, brctl, ifconfig, route, netstat, iwconfig, and a bunch of others that I'm probably forgetting.  What really floors me, though, is that most of these tools configure a network interface ... yet aren't part of ifconfig (the interface configuration tool).  [shakes head]  It truly boggles the mind how disorganised and all-over-the-place things are in Linux-land.

Re: Some quick Linux thoughts

lucas wrote:

that's dumb. i also don't know how to list apt-get-installed packages.

% dpkg -l
"religions, worst damnation of mankind"
[color=Blue]Linux is not UNIX! Face it! It is not an insult. It is fact: GNU is a recursive acronym for

Re: Some quick Linux thoughts

I think that does the same thing as --get-selections. all the ridiculous shit like adduser and less are still listed.

Re: Some quick Linux thoughts

Don't shoot the messenger, but I think that on Debian/Ubuntu everything except the kernel and some minor stuff in /bin, /lib, etc. (ls, cat) is a package ... This includes basic tools like adduser, less, ifconfig, etc.

Trust me, I know what I'm doing.

Re: Some quick Linux thoughts

I know; that's what I figured. I just think it's annoying and silly.

Re: Some quick Linux thoughts

diff, less, adduser, ...

sigh

Re: Some quick Linux thoughts

It's the way Linux works ... It has some advantages ... But it's not my preferred method either (Which is one reason I'm using BSD).

Trust me, I know what I'm doing.

Re: Some quick Linux thoughts

Carpetsmoker wrote:

Don't shoot the messenger, but I think that on Debian/Ubuntu everything except the kernel and some minor stuff in /bin, /lib, etc. (ls, cat) is a package ... This includes basic tools like adduser, less, ifconfig, etc.

Absolutely everything in Debian is part of a package.

Re: Some quick Linux thoughts

Been using Linux at work for the last few months. I've grown a serious hatred for SELinux.

Last edited by Carpetsmoker (2010-10-06 17:21:51)

Trust me, I know what I'm doing.