Checking link status according to DIB_DHCP_TIMEOUT

In slow networks like Infiniband it takes much time for the
interface to get the carrier. This patch enables this service
to run more then 20 seconds and limited by DIB_DHCP_TIMEOUT.

Change-Id: I8a6015567ac25e37b5a5aba4b1fda71170cc144a

diskimage_builder/elements/dhcp-all-interfaces/README.rst

@@ -25,5 +25,5 @@ DIB_DHCP_TIMEOUT
   :Required: No
   :Default: 30
   :Description: Amount of time in seconds that the systemd service will
-   wait to get an address.
+   wait to get an address. Should be increased in networks such as Infiniband.
   :Example: DIB_DHCP_TIMEOUT=300

diskimage_builder/elements/dhcp-all-interfaces/install.d/50-dhcp-all-interfaces

@@ -11,6 +11,7 @@ SCRIPTDIR=$(dirname $0)
 # this script is not needed on Gentoo.
 if [ "$DISTRO_NAME" != "gentoo" ]; then
     install -D -g root -o root -m 0755 ${SCRIPTDIR}/dhcp-all-interfaces.sh /usr/local/sbin/dhcp-all-interfaces.sh
+    sed -i "s/DIB_DHCP_TIMEOUT/${DIB_DHCP_TIMEOUT:-30}/" /usr/local/sbin/dhcp-all-interfaces.sh
 fi
 
 if [ "$DIB_INIT_SYSTEM" == "upstart" ]; then

diskimage_builder/elements/dhcp-all-interfaces/install.d/dhcp-all-interfaces.sh

@@ -97,8 +97,8 @@ function inspect_interface() {
         echo "Device has generated MAC, skipping."
     else
         local has_link
-        local tries
-        for ((tries = 0; tries < 20; tries++)); do
+        local tries=DIB_DHCP_TIMEOUT
+        for ((; tries > 0; tries--)); do
             # Need to set the link up on each iteration
             ip link set dev $interface up &>/dev/null
             has_link=$(get_if_link $interface)