Share my minds

piątek, 17 stycznia 2014

Secure web directory with exclude

Last time I needed to secure on of my websites. I set password, used htaccess and ...I got error on my main page. The reason was simple - main page invoked to file in my secure directory. I needed to exclude this file from my secure directory. Below is solution.

# password protection allowing multiple resources
AuthType Basic
AuthName "Restricted Area"
AuthUserFile /home/path/.htpasswd
AuthGroupFile /dev/null 
Require valid-user
# allow public access to the following resources
SetEnvIf Request_URI "(path/to/directory_01/)$"         allow
SetEnvIf Request_URI "(path/to/directory_02/)$"         allow
SetEnvIf Request_URI "(path/to/file\.php)$"             allow
SetEnvIf Request_URI "(path/to/file\.html)$"            allow
SetEnvIf Request_URI "(path/to/another/resource/)$"     allow
SetEnvIf Request_URI "(path/to/yet/another/resource/)$" allow
Order allow,deny
Allow from env=allow
Satisfy any

Of course you can also use "Allow from " to limiting access to secure directory.

niedziela, 29 grudnia 2013

The $5 eBook Bonanza

Packt has announced the $5 eBook Bonanza to mark the commencement of this holiday season! Starting from 19 December 2013 till 3rd Jan 2014, customers will be able to get any eBook or Video from Packt for just $5.

środa, 20 listopada 2013

mdadm "lost" discs

A few days ago I had to stop my systems. One of them had different kind of storage like: luns, nfs and software raids. After turned on system I realized that I had had no software raid. I checked if everything was connected and checked if discs exists.

mdadm --examine /dev/sd[b-t]

/dev/sdc:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : da8f3a5d:10f75bee:f074ba7e:f0494c09

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : d24bdccc - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 7
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdd:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : c4d19ddc:f5dc1884:c6ef0844:3abe1c66

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : 98af3bd - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 8
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sde:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 51e205a2:40aa348f:3f2041a9:872d3e1f

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : f868715b - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 9
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdf:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 1832c689:2cb35bfc:d2c97cf5:d84c985d

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : d7e592ea - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 0
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdg:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 5a9a6781:53904dfc:0f5789c9:e0df60e8

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : 2e4df89a - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 1
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdh:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : afa5008b:efc248ab:5ab3bce0:2def6ad1

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : e71fa223 - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 2
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdi:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : c8e16d74:a1940d4c:5a802c6a:5173a94c

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : 76000112 - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 3
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdj:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 53051171:604d9634:a7f5c2b6:14c2bddd

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : 38d6a16e - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 4
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdk:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : fc3706df:d1f2df92:f50a37a7:55fd1845

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : 5ce4ca18 - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 5
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)
/dev/sdl:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 2632f0c3:b113d4e9:056228c1:d30a6ab0
           Name : synat2:0  (local to host synat2)
  Creation Time : Tue Dec 11 13:59:58 2012
     Raid Level : raid0
   Raid Devices : 10

 Avail Dev Size : 47997696 (22.89 GiB 24.57 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
          State : clean
    Device UUID : 6ae2fd1e:30297e6c:4a26a015:2edcfe2c

    Update Time : Tue Dec 11 13:59:58 2012
       Checksum : ccc9a512 - correct
         Events : 0

     Chunk Size : 512K

   Device Role : Active device 6
   Array State : AAAAAAAAAA ('A' == active, '.' == missing)

Than I realized that in my mdadm.conf were entries with /dev/dm-*. It means that something was wrong because in /dev I had only 4 entries contained dm*. It turned out that my multipath configuration blocked other dm-* devices to be discovered. I switched dm to disk/by-id.

root@testing:~# cat /etc/mdadm/mdadm.conf  | grep -v ^#

CREATE owner=root group=disk mode=0660 auto=yes
HOMEHOST 
MAILADDR root
DEVICE /dev/disk/by-id/scsi-SATA_MARVELL_*

Did:

root@testing:~# mdadm --assemble --scan

and

root@testing:~# mount -a

Now everything works as it should.

wtorek, 29 października 2013

FreeBSD access via Xen console

To allow access via xen console you need to change /etc/ttys:

-ttyu0 /usr/libexec/getty std.9600 dialup off secure
+ttyu0 /usr/libexec/getty std.9600 dialup on secure

Than add few lines into /boot/loader.conf :

boot_multicons="YES"
boot_serial="YES"
comconsole_speed=9600
console="comconsole,vidconsole"

Now you can restart server.

Now you can access to FreeBSD console via xen:

[root@xenserver1 ~]# xl console "FreeBSD 9.2"

FreeBSD/amd64 (tanatos) (ttyu0)

login:

To end session on console please enter Ctrl+]

piątek, 25 października 2013

Xen add new virtual disc

Once I need to attach new disk on my VM machine. To do this I need make steps below :

1) Get storage UUID:

[root@xenserver1 ~]# xe sr-list 
uuid ( RO)                : 4e98e18e-1215-4fdb-baec-924bbef2a67e
          name-label ( RW): Remote ISO Library on: /mnt/iso_import
    name-description ( RW): 
                host ( RO): xenserver1
                type ( RO): iso
        content-type ( RO): iso


uuid ( RO)                : f30a1ead-37f2-0e3c-9583-073c176fc111
          name-label ( RW): Removable storage
    name-description ( RW): 
                host ( RO): xenserver1
                type ( RO): udev
        content-type ( RO): disk


uuid ( RO)                : 419c98d3-1d98-3049-c579-439c31b33fd4
          name-label ( RW): XenServer Tools
    name-description ( RW): XenServer Tools ISOs
                host ( RO): xenserver1
                type ( RO): iso
        content-type ( RO): iso


uuid ( RO)                : a9329bfa-e13e-2edd-8414-5920f03f27e5
          name-label ( RW): ISOS
    name-description ( RW): 
                host ( RO): xenserver1
                type ( RO): iso
        content-type ( RO): iso


uuid ( RO)                : cb128245-3dcb-9de6-319d-681cede9553f
          name-label ( RW): DVD drives
    name-description ( RW): Physical DVD drives
                host ( RO): xenserver1
                type ( RO): udev
        content-type ( RO): iso


uuid ( RO)                : f6375e1e-0ab7-b11c-e9dd-677da4436e15
          name-label ( RW): Local storage
    name-description ( RW): 
                host ( RO): xenserver1
                type ( RO): lvm
        content-type ( RO): user

2) Create virtual disc:

[root@xenserver1 ~]# xe vdi-create name-label="zfs1" sr-uuid=f6375e1e-0ab7-b11c-e9dd-677da4436e15 type=user sm-config:type=raw virtual-size=10GiB
34a899b3-b3dd-4531-aee9-1fafb57517ca
[root@xenserver1 ~]# xe vdi-create name-label="zfs2" sr-uuid=f6375e1e-0ab7-b11c-e9dd-677da4436e15 type=user sm-config:type=raw virtual-size=10GiB
20c384f6-0504-4c7f-a3cf-08d28c6c0dc6
[root@xenserver1 ~]# xe vdi-list name-label=zfs1
uuid ( RO)                : 34a899b3-b3dd-4531-aee9-1fafb57517ca
          name-label ( RW): zfs1
    name-description ( RW): 
             sr-uuid ( RO): f6375e1e-0ab7-b11c-e9dd-677da4436e15
        virtual-size ( RO): 10737418240
            sharable ( RO): false
           read-only ( RO): false


[root@xenserver1 ~]# xe vdi-list name-label=zfs2
uuid ( RO)                : 20c384f6-0504-4c7f-a3cf-08d28c6c0dc6
          name-label ( RW): zfs2
    name-description ( RW): 
             sr-uuid ( RO): f6375e1e-0ab7-b11c-e9dd-677da4436e15
        virtual-size ( RO): 10737418240
            sharable ( RO): false
           read-only ( RO): false

3) Check virtual machine UUID for whom virtual disc should be attched:

[root@xenserver1 ~]# xe vm-list 
uuid ( RO)           : 68ce65a4-01ec-4a23-9016-011aa20e59cf
     name-label ( RW): Control domain on host: xenserver1
    power-state ( RO): running


uuid ( RO)           : 66a6fcc2-b5b9-1eb9-cd26-c26d8df1e204
     name-label ( RW): Hadoop-master
    power-state ( RO): running


uuid ( RO)           : a79bc6f8-54d7-a562-ba14-4f50db2efc9b
     name-label ( RW): FreeBSD 9.2
    power-state ( RO): running


uuid ( RO)           : 8ac1c052-8448-6d9b-0a55-6e91e5be406c
     name-label ( RW): FreeBSD10
    power-state ( RO): halted


uuid ( RO)           : 03070e1e-2b04-5e4b-87f9-5db7d69131bb
     name-label ( RW): Hadoop-slave2
    power-state ( RO): running


uuid ( RO)           : d122b3bf-e914-83b0-5761-1430f205fa9c
     name-label ( RW): Hadoop-slave1
    power-state ( RO): running

In my case it was FreeBSD 9.2 (uuid=a79bc6f8-54d7-a562-ba14-4f50db2efc9b)

4) Get allowed numbers for VBD devices:

[root@xenserver1 ~]# xe vm-param-get uuid=a79bc6f8-54d7-a562-ba14-4f50db2efc9b param-name=allowed-VBD-devices 
1; 2

5) Create virtual disc attached to VM:

[root@xenserver1 ~]# xe vbd-create device=1 vm-uuid=a79bc6f8-54d7-a562-ba14-4f50db2efc9b vdi-uuid=34a899b3-b3dd-4531-aee9-1fafb57517ca bootable=false mode=RW type=Disk
f43711c3-be1e-a869-8888-408d94a70656
[root@xenserver1 ~]# xe vbd-create device=2 vm-uuid=a79bc6f8-54d7-a562-ba14-4f50db2efc9b vdi-uuid=20c384f6-0504-4c7f-a3cf-08d28c6c0dc6 bootable=false mode=RW type=Disk
5dcf7ad9-f4ec-b3e3-ea0c-8edd0d35d53d

6) Optionally if you have Xen tools on board you can plug virtual disc live.

[root@xenserver1 ~]# xe vbd-plug uuid=f43711c3-be1e-a869-8888-408d94a70656

If everything goes right you should have new discs attached and working on virtual machine. On system:

shamrock@tanatos:~ % dmesg | grep xbd
xbd0: 30720MB  at device/vbd/768 on xenbusb_front0
xbd0: attaching as ada0
xbd1: 10240MB  at device/vbd/5632 on xenbusb_front0
xbd1: attaching as ada2
xbd2: 10240MB  at device/vbd/832 on xenbusb_front0
xbd2: attaching as ada1

On Xen:

[root@xenserver1 ~]# xe vbd-list vm-name-label=FreeBSD\ 9.2
uuid ( RO)             : 5dcf7ad9-f4ec-b3e3-ea0c-8edd0d35d53d
          vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
    vm-name-label ( RO): FreeBSD 9.2
         vdi-uuid ( RO): 20c384f6-0504-4c7f-a3cf-08d28c6c0dc6
            empty ( RO): false
           device ( RO): hdc


uuid ( RO)             : f43711c3-be1e-a869-8888-408d94a70656
          vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
    vm-name-label ( RO): FreeBSD 9.2
         vdi-uuid ( RO): 34a899b3-b3dd-4531-aee9-1fafb57517ca
            empty ( RO): false
           device ( RO): hdb


uuid ( RO)             : 17d014d8-0d28-76e9-b6dc-f8944a0c0244
          vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
    vm-name-label ( RO): FreeBSD 9.2
         vdi-uuid ( RO): a74f372f-2fcd-4121-a241-bd1e960a069c
            empty ( RO): false
           device ( RO): hda

środa, 23 października 2013

Create local ISO repository

Create with lvcreate place for repository:

[root@xenserver1 ~]# lvcreate -L 30G -n ISO2 VG_XenStorage-f6375e1e-0ab7-b11c-e9dd-677da4436e15

Make proper file system:

[root@xenserver1 ~]# mkfs.ext3 /dev/VG_XenStorage-f6375e1e-0ab7-b11c-e9dd-677da4436e15/ISO2

Add lines to /ec/rc.local

[root@xenserver1 ~]# vi /etc/rc.local


ISO=/dev/VG_XenStorage-f6375e1e-0ab7-b11c-e9dd-677da4436e15/ISO2
lvchange -ay $ISO
mount $ISO /mnt/iso_import

It's very important not to change /etc/fstab !!!

Last thing is to mount everything without restart:

[root@xenserver1 ~]# ISO=/dev/VG_XenStorage-f6375e1e-0ab7-b11c-e9dd-677da4436e15/ISO2
[root@xenserver1 ~]# lvchange -ay $ISO
[root@xenserver1 ~]# mount $ISO /mnt/iso_import
[root@xenserver1 ~]# xe-mount-iso-sr /mnt/iso_import -o bind

Result:

[root@xenserver1 ~]# xe sr-list
uuid ( RO)                : 4e98e18e-1215-4fdb-baec-924bbef2a67e
          name-label ( RW): Remote ISO Library on: /mnt/iso_import
    name-description ( RW): 
                host ( RO): xenserver1
                type ( RO): iso
        content-type ( RO): iso


uuid ( RO)                : f30a1ead-37f2-0e3c-9583-073c176fc111
          name-label ( RW): Removable storage
    name-description ( RW): 
                host ( RO): xenserver1
                type ( RO): udev
        content-type ( RO): disk


uuid ( RO)                : 419c98d3-1d98-3049-c579-439c31b33fd4
          name-label ( RW): XenServer Tools
    name-description ( RW): XenServer Tools ISOs
                host ( RO): xenserver1
                type ( RO): iso
        content-type ( RO): iso


uuid ( RO)                : cb128245-3dcb-9de6-319d-681cede9553f
          name-label ( RW): DVD drives
    name-description ( RW): Physical DVD drives
                host ( RO): xenserver1
                type ( RO): udev
        content-type ( RO): iso


uuid ( RO)                : f6375e1e-0ab7-b11c-e9dd-677da4436e15
          name-label ( RW): Local storage
    name-description ( RW): 
                host ( RO): xenserver1
                type ( RO): lvm
        content-type ( RO): user

How to add network interface to VM on Citrix Xen via console

Check interfaces:

[root@xenserver1 ~]# xe pif-list 
uuid ( RO)                  : cc9937fa-0435-7664-a73a-c9bfa803e50e
                device ( RO): eth3
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): e7a75876-ee65-950e-7975-6751eca3795b


uuid ( RO)                  : 3a5ef383-650a-ded9-d636-4c86a6831443
                device ( RO): eth1
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): bd91ea1e-6184-4f7b-6360-0134f39b9751


uuid ( RO)                  : 4c04ef06-9707-67ac-1859-6e6617d507a7
                device ( RO): eth2
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): 8d829397-e8d1-fdc2-b62d-8b23cf6da7dd


uuid ( RO)                  : 41b55f45-91ff-90e1-0a13-dbb680e744e9
                device ( RO): eth0
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): 78613a9f-aede-edc6-39f4-40c4c5883de2


uuid ( RO)                  : 72ff5545-3d4b-5038-aa15-dc93998b8dab
                device ( RO): eth0
    currently-attached ( RO): true
                  VLAN ( RO): 21
          network-uuid ( RO): 8310ea88-dad4-c989-19db-5c5fdb8d3edc

Create internal interface - not bounded to any physical interface :

[root@xenserver1 ~]# xe network-create name-label="anylan" name-description="anylan for testing"
919b5b1c-201f-fed2-c39d-21946f278bdc

Create tagged network interface bounded to physical NIC:

[root@xenserver1 ~]# xe network-create name-label="vlan402" name-description="VLAN 402" 
d5b6969c-eff4-79b2-0088-7740f8a9b492


[root@xenserver1 ~]# xe vlan-create network-uuid=d5b6969c-eff4-79b2-0088-7740f8a9b492 pif-uuid=41b55f45-91ff-90e1-0a13-dbb680e744e9  vlan=402
7dadd3ec-b8a2-5b40-0855-0ef365dc9f00

Example pif-list after adding new interface

[root@xenserver1 ~]# xe pif-list 
uuid ( RO)                  : 7dadd3ec-b8a2-5b40-0855-0ef365dc9f00
                device ( RO): eth0
    currently-attached ( RO): true
                  VLAN ( RO): 402
          network-uuid ( RO): d5b6969c-eff4-79b2-0088-7740f8a9b492


uuid ( RO)                  : cc9937fa-0435-7664-a73a-c9bfa803e50e
                device ( RO): eth3
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): e7a75876-ee65-950e-7975-6751eca3795b


uuid ( RO)                  : 3a5ef383-650a-ded9-d636-4c86a6831443
                device ( RO): eth1
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): bd91ea1e-6184-4f7b-6360-0134f39b9751


uuid ( RO)                  : 4c04ef06-9707-67ac-1859-6e6617d507a7
                device ( RO): eth2
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): 8d829397-e8d1-fdc2-b62d-8b23cf6da7dd


uuid ( RO)                  : 41b55f45-91ff-90e1-0a13-dbb680e744e9
                device ( RO): eth0
    currently-attached ( RO): true
                  VLAN ( RO): -1
          network-uuid ( RO): 78613a9f-aede-edc6-39f4-40c4c5883de2


uuid ( RO)                  : 72ff5545-3d4b-5038-aa15-dc93998b8dab
                device ( RO): eth0
    currently-attached ( RO): true
                  VLAN ( RO): 21
          network-uuid ( RO): 8310ea88-dad4-c989-19db-5c5fdb8d3edc

Check VM to attach new interface: we need to know number of devices and vm-uuid.

[root@xenserver1 ~]# xe vm-list 
uuid ( RO)           : 68ce65a4-01ec-4a23-9016-011aa20e59cf
     name-label ( RW): Control domain on host: xenserver1
    power-state ( RO): running


uuid ( RO)           : 66a6fcc2-b5b9-1eb9-cd26-c26d8df1e204
     name-label ( RW): Hadoop-master
    power-state ( RO): running


uuid ( RO)           : a79bc6f8-54d7-a562-ba14-4f50db2efc9b
     name-label ( RW): FreeBSD 9.2
    power-state ( RO): running


uuid ( RO)           : 8ac1c052-8448-6d9b-0a55-6e91e5be406c
     name-label ( RW): FreeBSD10
    power-state ( RO): halted


uuid ( RO)           : 03070e1e-2b04-5e4b-87f9-5db7d69131bb
     name-label ( RW): Hadoop-slave2
    power-state ( RO): running


uuid ( RO)           : d122b3bf-e914-83b0-5761-1430f205fa9c
     name-label ( RW): Hadoop-slave1
    power-state ( RO): running

[root@xenserver1 ~]# xe vif-list vm-name-label=FreeBSD\ 9.2
uuid ( RO)            : 49a107e2-0e81-a9dd-0595-218c07fe1af8
         vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
          device ( RO): 2
    network-uuid ( RO): 56d7fd62-ba47-c12c-e371-bc7908739ad1


uuid ( RO)            : 03932dbf-d7e4-ed7d-d649-ac431a97d962
         vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
          device ( RO): 1
    network-uuid ( RO): 8310ea88-dad4-c989-19db-5c5fdb8d3edc

Attach interface to VM:

[root@xenserver1 ~]# xe vif-create network-uuid=d5b6969c-eff4-79b2-0088-7740f8a9b492 vm-uuid=a79bc6f8-54d7-a562-ba14-4f50db2efc9b device=3 mac=random
758cf24a-2904-f3aa-8ed4-17d6ffebf032

[root@xenserver1 ~]# xe vif-create network-uuid=919b5b1c-201f-fed2-c39d-21946f278bdc  vm-uuid=a79bc6f8-54d7-a562-ba14-4f50db2efc9b  device=4 mac=random
3504d19f-2413-e066-6d30-1878adfbd117

Result:


[root@xenserver1 ~]# xe vif-list vm-name-label=FreeBSD\ 9.2
uuid ( RO)            : 49a107e2-0e81-a9dd-0595-218c07fe1af8
         vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
          device ( RO): 2
    network-uuid ( RO): 56d7fd62-ba47-c12c-e371-bc7908739ad1


uuid ( RO)            : 758cf24a-2904-f3aa-8ed4-17d6ffebf032
         vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
          device ( RO): 3
    network-uuid ( RO): d5b6969c-eff4-79b2-0088-7740f8a9b492


uuid ( RO)            : 03932dbf-d7e4-ed7d-d649-ac431a97d962
         vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
          device ( RO): 1
    network-uuid ( RO): 8310ea88-dad4-c989-19db-5c5fdb8d3edc


uuid ( RO)            : 3504d19f-2413-e066-6d30-1878adfbd117
         vm-uuid ( RO): a79bc6f8-54d7-a562-ba14-4f50db2efc9b
          device ( RO): 4
    network-uuid ( RO): 919b5b1c-201f-fed2-c39d-21946f278bdc

Depends of configuration probably you'll need to shutdown your machine and start it again thus system could determine network interface.