How do I bring up my wireless network at boot?

Failed to connect to wpa_supplicant - wpa_ctrl_open: Read-only file system

According to your log you 'll need to use wpa_supplicant.

So add something similar to this:

auto wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant.conf

Contents of /etc/wpa_supplicant.conf :

network={
        ssid="ADD-YOUR-SSID-HERE"
        proto=RSN
        key_mgmt=WPA-PSK
        pairwise=CCMP TKIP
        group=CCMP TKIP
        psk="ADD-YOUR-WPA-PASSWORD-HERE"
}

You can add ifup wlan0 to your /etc/rc.local file. Add the command ifup wlan0 before the exit 0. Also add the command ifdown wlan0 before the ifup wlan0 like so:

...
ifdown wlan0
ifup wlan0

exit 0

For some reason when Ubuntu starts, it thinks that wlan0 is up. So you have to shut it down and have it back up again.