VMs with identical UUID get mixed up

sascha

Dear all,

Due to incorrect provisioning two VMs in different vCenters have the same instanceUuid. This means, performance data gets mixed.

Possible fix: Append vcenter instance id+unique id or append vcenter alias to vm instance uuid to make it unique.

Thanks in advance!
Sascha

Pavel

Hi,

your right it would fix such incorrect provisioning.

Question is how often this might happen and if that justifies our effor into that.

Actually I do not see any priority here

Anyway thanks for idea!

sascha

Hi Pavel,

I just analyzed our environment and we have plenty of those system and the effort to change it is really high.

It would be great if you find some time to write a patch. I will also have a look at the code an maybe I can provide some sort of patch.


Thanks
Sascha

Pavel

Hi,

we have discussed it internally.

From implementation part it is not easy change, it has many consequences in our code.

There is also other general consequnce, if someone changed vcenter ID or running vcenter then he will lose all VM history in case this is implemented.

We are not going for this change for now.

sascha

Hi Pavel,

I tried to find a solution to the problem. Interestingly the combination of instanceuuid and uuid is unique. There are collisions for both seperately but not for the combination.

The implementation did not require a lot of changes in the code. Please have a look at the provided patch (uploading files here is not possible, so i just put it below).

Thanks
Sascha

------


--- vmw2rrd.pl.orig5.07_vcenterfix    2018-06-29 14:03:26.433707498 +0200
+++ vmw2rrd.pl    2018-07-27 09:14:32.763121798 +0200

       #  new lpar will be added to lpar_trans.txt
       my $each_vm_uuid = $each_vm->{'summary.config.instanceUuid'};
       my $each_vm_uuid_old = $each_vm->{'summary.config.uuid'};
+      ##### Sascha added - combine both IDs as only this is unique in our environment
+      $each_vm_uuid .= "_".$each_vm_uuid_old;
+      $each_vm_uuid_old .= "_".$each_vm_uuid;
+      #####
       my $each_vm_name = $each_vm->{'name'};
       my $each_vm_url  = $each_vm_name;
 

   for ( my $i = 0; $i < scalar @$a_ref; $i++ ) {
     my $pos = rindex( @$a_ref[$i], ':' );
     next if $pos < 0;                                         # some trash
-    next if ( substr( @$a_ref[$i], 0, 36 ) ne "$vm_uuid" );
+    # As the ID now consists of 36+1+36 chars, edited from 36 to 73
+    next if ( substr( @$a_ref[$i], 0, 73 ) ne "$vm_uuid" );
     if ( substr( @$a_ref[$i], $pos + 1, 3 ) eq "sta" ) {      # keep item
       substr( @$a_ref[$i], length( @$a_ref[$i] ) - 1, 5 ) = ":act\n";
       $found++;

   print "date load      : $host:$managedname $date\n" if $DEBUG;
 } ## end sub prepare_last_time
 
-# provides easy uuid check, pays for 1 arg only
+##### Sascha added - combine both IDs as only this is unique in our environment
+# provides easy uuid check, pays for 1 arg only, for double uuids
 sub uuid_check {
 
-  return ( $_[0] =~ m{.{8}-.{4}-.{4}-.{4}-.{12}} )
+  return ( $_[0] =~ m{.{8}-.{4}-.{4}-.{4}-.{12}_.{8}-.{4}-.{4}-.{4}-.{12}} )
 
 }
 

 
     # print "\$numCpu $numCpu\n";
     $vm_uuid_active = $entity->summary->config->instanceUuid;
+    ##### Sascha added - combine both IDs as only this is unique in our environment
+    # ignored return if not defined
+    $vm_uuid_active .= "_".$entity->summary->config->uuid;
+    #####
     return if not defined $vm_uuid_active;    # there can exist poweredOn VM with UNSET instanceUuid
 
     $last_file = "$vm_uuid_active.last";

       $cpu_res     = $entity->config->cpuAllocation->reservation;
       $numCpu      = $entity->summary->config->numCpu;
       $entity_uuid = $entity->summary->config->instanceUuid;
+      ##### Sascha added - combine both IDs as only this is unique in our environment
+      $entity_uuid .= "_".$entity->summary->config->uuid;
+      #####
 
       # print "2709 vmw2rrd.pl \$vm_moref $vm_moref $numCpu $cpu_res $entity_uuid\n";
       my @temp_arr = ();

audifilm

I had same problem and solved editing .vmx for VMs with duplicated UUID and changing line with vc.uuid.

I generated a new random GUID from inside Linux appliance with command:
uuidgen | perl -ne '{ s/-//g; s/(.{2})/\1 /g; substr($_,23,1,"-"); print ; }'

Example:

[root@xorux lpar2rrd]# uuidgen | perl -ne '{ s/-//g; s/(.{2})/\1 /g; substr($_,23,1,"-"); print ; }'

63 f7 66 c1 a1 ec 41 82-9c 94 0a 40 2e ab b1 2f

[root@nsxxxxx:/vmfs/volumes/583583cd-14cfa730-9f12-0cc47ade9a08/VMsample] vi VMsample.vmx

vc.uuid = "63 f7 66 c1 a1 ec 41 82-9c 94 0a 40 2e ab b1 2f"

Then I purged all data an forced a reload with:

cd /home/lpar2rrd/lpar2rrd/data
rm -rf *
rm -f /home/lpar2rrd/lpar2rrd/data/vmware_VMs/*
su lpar2rrd /home/lpar2rrd/lpar2rrd/load.sh

Best regards!