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Subsonic Under Tomcat & Gentoo

You might be seeing non-working audio output and the following tricky bits in your subsonic log:

Error in jukebox: javax.sound.sampled.LineUnavailableException: Audio Device Unavailable

First thing is to make sure you’re running the Sun JDK and not OpenJDK or something else. Apparently there are things that don’t play well with non-Sun.

If you’ve done this, restarted Tomcat and still have no audio when using Subsonic with Gentoo and Tomcat, remember to add Tomcat to the relevant groups:

groupmems -g pulse -a tomcat

groupmems -g pulse-access -a tomcat

groupmems -g audio -a tomcat

groupmems -g plugdev -a tomcat

To be fair I’m not sure if they’re all necessary, but it works for me. You’ll need to restart Tomcat afterward to make it work.

sudo /etc/init.d/tomcat-6 restart

OpenVZ: VLAN with VEs that Works

So I setup OpenVZ a few months ago in an environment where my Host had two NICs, one on a local “office” network, and another hooked directly up to a WiFi AP that had VLAN’d SSIDs. That part’s not too important, but what is important is the VLANs. It seemed real easy when I did it back then.

However, having to re-do it again for various reasons without the source config, it was not so easy. In fact, I wasted nearly half a day until I figured out you need to add the veth device and the Host adapter to a bridge to even route the traffic properly. The key understanding is that the veth device for OpenVZ has absolutely no relation to any network adapter on the HN. Understand that and you’ll be OK. All it does is create an interface on the HN whose other side is on the VE.

So to save myself some hellish boot configuration, I modified vznetaddbr (below) to create the bridges and bring everything up real nice for me. The key bits are that you defined your veth device with a bridge parameter called ‘vlan###’ where ### is the vlan ID. You’ll also need to change the line near the top that says dev=eth1, unless eth1 is your VLAN’d NIC.

Really, hopefully this helps someone. Should be self-explanatory, but be sure you have brctl and vconfig installed.

# create this file somewhere, and add it to
# /etc/vz/vznet.conf as:
#
#!/bin/bash
#EXTERNAL_SCRIPT="/path/to/script"
#
# be sure to chmod +x both
 
CONFIGFILE=/etc/vz/conf/$VEID.conf
. $CONFIGFILE
 
NETIFLIST=$(printf %s "$NETIF" |tr ';' '\n')
dev="eth1"
ip link set dev "$dev" up
 
if [ -z "$NETIFLIST" ]; then
   echo >&2 "According to $CONFIGFILE, CT$VEID has no veth interface configured."
   exit 1
fi
 
for iface in $NETIFLIST; do
    bridge=
    host_ifname=
 
    for str in $(printf %s "$iface" |tr ',' '\n'); do
        case "$str" in
            bridge=*|host_ifname=*)
                eval "${str%%=*}=\${str#*=}" ;;
        esac
    done
 
#    [ "$host_ifname" = "$3" ] ||
#       continue
 
    [ -n "$bridge" ] ||
        bridge=vmbr0
 
    vlan=`echo "$bridge" | sed s/vlan//`
    target_if="eth1.$vlan"
 
    echo "Creating $bridge on CT0"
    brctl addbr "$bridge"
    echo "Adding interface $host_ifname to bridge $bridge on CT0 for CT$VEID"
    ip link set dev "$host_ifname" up
    brctl addif "$bridge" "$host_ifname"
    echo 1 >"/proc/sys/net/ipv4/conf/$host_ifname/proxy_arp"
    echo 1 >"/proc/sys/net/ipv4/conf/$host_ifname/forwarding"
 
    echo "Creating interface $target_if on CT0 for CT$VEID"
    vconfig add "$dev" "$vlan"
    echo "Adding interface $host_ifname to bridge $bridge on CT0 for CT$VEID"
    ip link set dev "$target_if" up
    brctl addif "$bridge" "$target_if"
    echo 1 >"/proc/sys/net/ipv4/conf/$target_if/proxy_arp"
    echo 1 >"/proc/sys/net/ipv4/conf/$target_if/forwarding"
 
    ip link set dev "$bridge" up
 
done
 
exit 0

Fix ‘Nautilus Hangs When Viewing Properties’

If you get hangs in Nautilus when attempting to view file properties, do the following:

rm -rf ~/.thumbnails
killall nautilus

Should be good after that!

Recursive Search and Replace in *Nix

grep -rl matchstring somedir/ | xargs sed -i 's/string1/string2/g'

The Source

Fixing MySQLdb encoding issues with Python

Are you running into encoding issues with MySQLdb on Python? Have you searched high and low only to be told to change your my.cnf settings and create tables with the proper encoding, yet it STILL doesn’t work? In that case, be sure to specify charset='utf8' in your MySQLdb.connect(...) along with the rest of the required parameters. This tiny, neglected setting is what’s actually used to encode unicode back for MySQL. Not configuration files, not table settings, just that.

Of course, you should have a table with a utf8 charset for it to work, but this is the setting that will prevent those latin-1 encoding issues when you swore you didn’t say latin-1 anywhere.