Rich0's Gentoo Blog

Gentoo EC2 Tutorial / Bootstrapping

with 4 comments

I want to accomplish a few things with this post.

First, I’d like to give more attention to the work recently done by edowd on Bootstrapping Gentoo in EC2.

Second, I’d like to introduce a few enhancements I’ve made on these (some being merged upstream already).

Third, I’d like to turn this into a bit of a tutorial into getting started with EC2 as well since these scripts make it brain-dead simple.

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Written by rich0

September 24, 2012 at 10:20 am

Posted in foss, gentoo, linux

Gentoo Bug Bounties

with 7 comments

Some may have noticed that the Gentoo Foundation has funded a bug bounty. This is something fairly new for the Foundation, and I wanted to offer some comments on the practice. Please note that while I’d love to see some of these make their way into policy some day, these are nothing more than my own opinion, and I reserve the right to change my opinion as we gain experience.

The recent bug bounty was for bug #418431, which was to address a problem with git-svn which was holding up stabilization of the latest version of git, which is a blocker for the migration of the Portage tree to git.

What follows are some principles for the use of bug bounties and how I think we fared in this particular case. I’d like to see the use of bounties expand, as right now I believe we under-utilize our donations. However, it is important that bounties be used with care as they have the potential to cause harm or be wasteful.

One more upfront note – I supported the git-svn bounty as it was ultimately worded, as did the other Trustees. Looking back I think we could have done things a little differently, but hindsight is always 20/20, and no doubt we’ll continue to learn as we experiment with this further.

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Written by rich0

August 19, 2012 at 10:55 pm

MythTV ION Frustrations

with 2 comments

I figured I’d post another update on where things stand with MythTV on Gentoo. It looks like cardoe is finding some time to work on 0.25, which is good to see.

Right now my setup has the backend on Gentoo, and my set-top frontend on MiniMyth. This is a bit of a pain as it is hard to keep these in sync, so I’ve been trying to get this box onto Gentoo to greatly ease upgrades and allow me to update the tree.

However, I’m still running into issues making the switch. I’m running into issues with HD video artifacts on my frontend, which is a Zotac ION-based ITX board. These artifacts can be substantial – lasting tens of frames, causing tearing, leaving large pink areas on-screen, and so on. When I watch the same videos on MiniMyth sometimes I see no artifacts at all, and at other times I might see noise that lasts a frame.

So, something on the Gentoo build is causing minor defects in the stream to result in much more substantial ones by the time they are rendered. The Minimyth build is clearly more error-tolerant.

Unfortunately, I’m not very familiar with the entire rendering chain so I’m not sure which libraries could be at fault. If anybody is familiar with VDPAU rendering and has some suggestions I’m all ears.

Here is a link to the software installed on Gentoo.

Here is a link to the software installed on Minimyth.

Written by rich0

June 23, 2012 at 12:22 pm

Posted in Uncategorized

A Quick Dracut Module

with 6 comments

Since the general trend on many linux distros is towards requiring /usr to be mounted at boot time, I figured I’d see what it would take to get it working using dracut.

I’ve been messing with dracut for a while, and for some reason it stubbornly refuses to detect my raid devices. The kernel autodetection works fine, but this is disabled when booting from an initramfs. Dracut would timeout and drop me to a dash shell, and if I just typed mdadm -As followed by exit it would boot just fine.

Dracut is using udev to set up raid devices, and obviously that is not working.

Beyond this, I’d like to get my /usr mounted pre-boot, and there is a module called usrmount that purports to do just this. However, it isn’t working in my case because /usr is a bind mount to a subdir on an lvm volume, and it just isn’t figuring that out (it doesn’t even run lvm in the first place despite having the module installed, let alone figuring out what to mount in what order – I suspect the lvm module only works if root is on lvm).

My solution to both problems is to build my own simple dracut module. If you want to try it out:

  1. cd /usr/lib/dracut/modules.d/
  2. mkdir 91local
  3. cat > 91local/module-setup.sh
    #!/bin/bash
    # -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
    # ex: ts=8 sw=4 sts=4 et filetype=sh

    check() {
    return 0
    }

    depends() {
    return 0
    }

    install() {
    inst_hook pre-trigger 91 "$moddir/mount-local.sh"
    }

  4. cat > 91local/mount-local.sh
    #!/bin/sh
    # -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
    # ex: ts=8 sw=4 sts=4 et filetype=sh

    mount_local()
    {
    mdadm -As
    lvm pvscan
    lvm vgscan
    lvm lvscan
    lvm vgchange -ay
    }

    mount_local

Then run dracut to build your initramfs, and it should let mdadm and lvm auto-detect everything before it gets to mounting stuff. You can then use the fstab-sys to mount whatever you need to mount user. However, in your fstab.sys if you’re configuring a bindmount be sure to prepend /sysroot/ before the source directory.
Example fstab.sys:
/dev/vg1/data /data ext4 noatime,user_xattr,barrier=1 0 0
/sysroot/data/usr /usr none bind 0 0
/sysroot/data/var /var none bind 0 0

Hopefully this helps somebody out – the dracut documentation is pretty sparse. In fact, if somebody connected to dracut stumbles upon this I’d be open to a better way of hooking my script – pre-trigger just doesn’t seem right – I’d rather let udev try to do everything first. However, I couldn’t find any way to hook after udev runs but before it bombs out not finding my root device. Suggestions welcome.

Written by rich0

January 21, 2012 at 4:28 pm

Posted in gentoo, linux

Another MythTV Update

with 11 comments

Agreeing with some advice on gentoo-dev, I’m going to post this as a blog entry instead of a Gentoo news item. The quick version of this update is expect to see 0.24.1 in portage in a few days. The long version follows…
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Written by rich0

December 14, 2011 at 10:06 am

Posted in foss, gentoo, linux, mythtv

KDump on Gentoo

with 6 comments

I’ve been trying to learn a little more about kernel debugging (part of my quest to learn a little more about btrfs), and I figured I’d post a quick howto on getting kernel crash dumps captured on Gentoo.
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Written by rich0

November 11, 2011 at 9:45 pm

Posted in gentoo, linux

The Foundation Activity Tracker

with 4 comments

If you haven’t noticed on gentoo-nfp, I’ve created an activity tracking page (with the help of David Abbot) to track periodic compliance activities for the Foundation.

Some have asked why do this, and why not simply use the Gentoo Calendar/etc to accomplish this?
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Written by rich0

July 19, 2011 at 4:24 pm

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