src/initscripts/system/cloud-init

   1 #!/bin/sh
   2 ########################################################################
   3 # Begin $rc_base/init.d/cloud-init
   4 ########################################################################
   5
   6 . /etc/sysconfig/rc
   7 . ${rc_functions}
   8
   9 # https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/identify_ec2_instances.html
  10 running_on_ec2() {
  11         local uuid
  12
  13         # Check if the hypervisor UUID starts with ec2
  14         if [ -r "/sys/hypervisor/uuid" ]; then
  15                 uuid=$(</sys/hypervisor/uuid)
  16
  17                 [ "${uuid:0:3}" = "ec2" ] && return 0
  18         fi
  19
  20         # Check if the DMI product UUID starts with EC2
  21         if [ -r "/sys/devices/virtual/dmi/id/product_uuid" ]; then
  22                 uuid=$(</sys/devices/virtual/dmi/id/product_uuid)
  23
  24                 [ "${uuid:0:3}" = "EC2" ] && return 0
  25         fi
  26
  27         # We are not running on AWS EC2
  28         return 1
  29 }
  30
  31 case "${1}" in
  32         start)
  33                 # Do nothing if we are not running on AWS EC2
  34                 running_on_ec2 || exit 0
  35
  36                 # Find the first interface to use
  37                 for i in /sys/class/net/red* /sys/class/net/eth* \
  38                                 /sys/class/net/*; do
  39                         [ -d "${i}" ] || continue
  40                         i=$(basename ${i})
  41
  42                         # Skip loopback
  43                         [ "${i}" = "lo" ] && continue
  44
  45                         # Use whatever we have found
  46                         intf="${i}"
  47                         break
  48                 done
  49
  50                 # Check if we found a network interface
  51                 if [ ! -n "${intf}" ]; then
  52                         echo_failure
  53
  54                         boot_mesg -n "Could not find a network interface" ${FAILURE}
  55                         boot_mesg "" ${NORMAL}
  56                 fi
  57
  58                 # Run a DHCP client and set up the system accordingly
  59                 dhclient -sf /etc/rc.d/helper/aws-setup "${intf}"
  60
  61                 # End DHCP client immediately
  62                 dhclient -sf /etc/rc.d/helper/aws-setup -r "${intf}" &>/dev/null
  63
  64                 # Rename network devices
  65                 udevadm trigger --action="add" --subsystem-match="net"
  66
  67                 exit 0
  68                 ;;
  69
  70         status)
  71                 if running_on_ec2; then
  72                         echo "This system is running on AWS EC2"
  73                         exit 0
  74                 else
  75                         echo "This system is NOT running on AWS EC2"
  76                         exit 1
  77                 fi
  78                 ;;
  79
  80         *)
  81                 echo "Usage: ${0} {start|status}"
  82                 exit 1
  83                 ;;
  84 esac
  85
  86 # End $rc_base/init.d/cloud-init