Changes between Initial Version and Version 1 of find-guest-with-ip

Timestamp:

Jun 9, 2016, 1:51:04 PM (9 years ago)

Author:

Jamie McClelland

Comment:

--

find-guest-with-ip

@@ +1 @@
+= Find guest that has the given IP address =
+
+Sometimes we have an IP address and we want to find out which guest is configured to use it.
+
+There are several ways to do this.
+
+== dig ==
+
+The easiest way is to look for a reverse DNS entry (ptr) using dig:
+
+{{{
+0 jamie@turkey:~$ dig +short -x 209.51.172.13
+chavez.mayfirst.org.
+0 jamie@turkey:~$ 
+}}}
+
+== Check Puppet ==
+
+If that fails and you have access to our [wiki:puppet puppet repository], you can grep the puppet repo:
+
+{{{
+0 jamie@turkey:confdir$ grep 209.51.172.13 manifests/nodes/production/*.pp
+manifests/nodes/production/chavez.pp:  mayfirst::m_interface::set { "209.51.172.13/28": gateway => "209.51.172.1" }
+manifests/nodes/production/chavez.pp:     address => "209.51.172.13",
+manifests/nodes/production/parsi.pp:      guest_ipaddress => "209.51.172.13",
+0 jamie@turkey:confdir$
+}}}
+
+These results show that the IP is assigned to chavez (also note that chavez is a guest on parsi).
+
+Sometimes the grep will show more results than you expect (for example if you search for 209.51.172.1, you might also get 209.51.172.12, 209.51.172.13 etc).
+
+= From the host =
+
+If all else fails, you can search by MAC address.
+
+The first step is to determine the MAC address of the IP address. You can find that out by running the following command from any server in the same subnet:
+
+{{{
+ping -c1 209.51.172.13 && arp -an | grep 209.51.172.13
+}}}
+
+The first command sends a ping to the IP address (which will fill the arp table on the host) and the second command gets a listing of the arp table and filters by the IP address we are looking for.
+
+In our case we get:
+
+{{{
+? (209.51.172.13) at 02:c3:88:54:1d:8c [ether] on eth0
+}}}
+
+Now, iterate over all physical hosts and grep the output of ps to find the running kvm instance with a matching mac address.
+
+{{{
+for foo in $(freepuppet-helper ls:m_physical); do echo $foo && ssh root@$foo.mayfirst.org "ps -eFH | grep [mac]=02:c3:88:54:1d:8c"; done
+}}}