pk stuff

Docker inspect provides all sorts of useful information. Use with no format to get all values, then use –format to filter.

This example gets the complete container Id:

docker inspect –format='{{.Id}}’ $SHORT_CONTAINER_ID

While packaging minidlna in a Docker container, it became clear that IP Broadcasts (required by minidlna) are not bridged by default in Ubuntu 14.04.

Adding the following file (10-fix-bridge.conf) with the following to /etc/sysctl.d/ fixes this:

# allows broadcasts to reach Docker containers
#net.bridge.bridge-nf-call-arptables = 1
#net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 0

First, my ISP doesn’t support IPv6 so Linux works but DNS name lookups take forever. This helps.

Create a file named 10-no-ipv6.conf in /etc/sysctl.d/ with the following:

# No IPv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

Sometime I’m in a hurry and delete a VM’s disk image before removing it from libvirt/virsh, which leaves a lingering, dead reference to that VM.
The following fixes this:

sudo virsh –connect qemu:///system undefine vm_to_be_removed

Replace vm_to_be_removed with your VM name.