Entries tagged systemd

Related tags: cron, debian, desktop, docker, jessie, ssd, wheezy.

The Jessie 8.2 point-release broke for me

Monday, 7 September 2015

I have about 18 personal hosts, all running the Jessie release of Debian GNU/Linux. To keep up with security updates I use unattended-upgrades.

The intention is that every day, via cron, the system will look for updates and apply them. Although I mostly expect it to handle security updates I also have it configured such that point-releases will be applied by magic too.

Unfortunately this weekend, with the 8.2 release, things broke in a significant way - The cron deamon was left in a broken state, such that all cronjobs failed to execute.

I was amazed that nobody had reported a bug, as several people on twitter had the same experience as me, but today I read through a lot of bug-reports and discovered that #783683 is to blame:

  • Old-cron runs.
  • Scheduled unattended-upgrades runs.
  • This causes cron to restart.
  • When cron restarts the jobs it was running are killed.
  • The system is in a broken state.

The solution:

# dpkg --configure -a
# apt-get upgrade

I guess the good news is I spotted it promptly, with the benefit of hindsight the bug report does warn of this as being a concern, but I guess there wasn't a great solution.

Anyway I hope others see this, or otherwise spot the problem themselves.

 

In unrelated news the seaweedfs file-store I previously introduced is looking more and more attractive to me.

I reported a documentation-related bug which was promptly handled, even though it turned out I was wrong, and I contributed CIDR support to whitelisting hosts which was merged in well.

I've got a two-node "cluster" setup at the moment, and will be expanding that shortly.

I've been doing a lot of little toy-projects in Go recently. This weekend I was mostly playing with the nats.io message-bus, and tying it together with sinatra.

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I eventually installed Debian on a new desktop.

Sunday, 7 December 2014

Recently I build a new desktop system. The hightlights of the hardware are a pair of 512Gb SSDs, which were to be configured in software RAID for additional speed and reliability (I'm paranoid that they'd suddenly stop working one day). From power-on to the (GNOME) login-prompt takes approximately 10 seconds.

I had to fight with the Debian installer to get the beast working though as only the Jessie Beta 2 installer would recognize the SSDs, which are Crucual MX100 devices. My local PXE-setup which deploys the daily testing installer, and the wheezy installer, both failed to recognize the drives at all.

The biggest pain was installing grub on the devices. I think this was mostly this was due to UFI things I didn't understand. I created spare partitions for it, and messaged around with grub-ufi, but ultimately disabled as much of the "fancy modern stuff" as I could in the BIOS, leaving me with AHCI for the SATA SSDs, and then things worked pretty well. After working through the installer about seven times I also simplified things by partitioning and installing on only a single drive, and only configured the RAID once I had a bootable and working system.

(If you've never done that it's pretty fun. Install on one drive. Ignore the other. Then configure the second drive as part of a RAID array, but mark the other half as missing/failed/dead. Once you've done that you can create filesystems on the various /dev/mdX devices, rsync the data across, and once you boot from the system with root=/dev/md2 you can add the first drive as the missing half. Do it patiently and carefully and it'll just work :)

There were some niggles though:

  • Jessie didn't give me the option of the gnome desktop I know/love. So I had to install gnome-session-fallback. I also had to mess around with ~/.config/autostart because the gnome-session-properties command (which should let you tweak the auto-starting applications) doesn't exist anymore.

  • Setting up custom keyboard-shortcuts doesn't seem to work.

  • I had to use gnome-tweak-tool to get icons, etc, on my desktop.

Because I assume the SSDs will just die at some point, and probably both on the same day, I installed and configured obnam to run backups. There is more testing and similar, but this is the core of my backup script:

#!/bin/sh

# backup "/" - minus some exceptions.
obnam backup -r /media/backups/storage --exclude=/proc --exclude=/sys --exclude=/dev --exclude=/media /

# keep files for various periods
obnam forget --keep="30d,8w,8m" --repository /media/backups/storage

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systemd, a brave new world

Thursday, 4 September 2014

After spending a while fighting with upstart, at work, I decided that systemd couldn't be any worse and yesterday morning upgraded one of my servers to run it.

I have two classes of servers:

  • Those that run standard daemons, with nothing special.
  • Those that run different services under runit
    • For example docker guests, node.js applications, and similar.

I thought it would be a fair test to upgrade one of each systems, to see how it worked.

The Debian wiki has instructions for installing Systemd, and both systems came up just fine.

Although I realize I should replace my current runit jobs with systemd units I didn't want to do that. So I wrote a systemd .service file to launch runit against /etc/service, as expected, and that was fine.

Docker was a special case. I wrote a docker.service + docker.socket file to launch the deamon, but when I wrote a graphite.service file to start a docker instance it kept on restarting, or failing to stop.

In short I couldn't use systemd to manage running a docker guest, but that was probably user-error. For the moment the docker-host has a shell script in root's home directory to launch the guest:

#!/bin/sh
#
# Run Graphite in a detached state.
#
/usr/bin/docker run -d -t -i -p 8080:80 -p 2003:2003 skxskx/graphite

Without getting into politics (ha), systemd installation seemed simple, resulted in a faster boot, and didn't cause me horrific problems. Yet.

ObRandom: Not sure how systemd is controlling prosody, for example. If I run the status command I can see it is using the legacy system:

root@chat ~ # systemctl status prosody.service 
prosody.service - LSB: Prosody XMPP Server
      Loaded: loaded (/etc/init.d/prosody)
      Active: active (running) since Wed, 03 Sep 2014 07:59:44 +0100; 18h ago
      CGroup: name=systemd:/system/prosody.service
          └ 942 lua5.1 /usr/bin/prosody

I've installed systemd and systemd-sysv, so I thought /etc/init.d was obsolete. I guess it is making pretend-services for things it doesn't know about (because obviously not all packages contain /lib/systemd/system entries), but I'm unsure how that works.

| 5 comments.

 

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