How to enable SNMP on Citrix XenServer 6

Today I needed to enable SNMP on my XenServer lab at home, I was looking for an efficient way to monitor my XenServer. I found a Linux distribution very handy for a Cacti box, EZCacti, you can download it here :

So to enable SNMP on XenServer 6, you need to follow the following guide. Please keep in memory you shouldn’t do that on your XenServer in a production environment, Citrix won’t be able to bring support if you modify the dom0.

First step, you need to allow SMTP to be able to collect and allow Cacti to get information from SNMP on the port 161/UDP :

Edit the file /etc/sysconfig/iptables with vi and add the following line :

/etc/sysconfig/iptables

-A RH-Firewall-1-INPUT -m state --state NEW -m udp -p udp --dport 161 -j ACCEPT

and then restart the iptables service using the following command line : service iptables restart

Now you need to configure your SNMP settings (community etc…) by editing the following file with vi : /etc/snmp/snmpd.conf

/etc/snmp/snmpd.conf

###############################################################################
# Access Control
###############################################################################
 
# As shipped, the snmpd demon will only respond to queries on the
# system mib group until this file is replaced or modified for
# security purposes.
 
####
# First, map the community name "public" into a "security name"
 
#       sec.name       source        community
com2sec archynet 192.168.0.0/24 public
 
####
# Second, map the security name into a group name:
 
#       groupName      securityModel securityName
group notConfigGroup v1 archynet
group   notConfigGroup v2c           notConfigUser
 
####
# Third, create a view for us to let the group have rights to:
 
#    name          incl/excl  subtree         mask(optional)
view    systemview    included   system
view    systemview    included   interfaces
view    systemview    included   at
view    systemview    included   ip
view    systemview    included   icmp
view    systemview    included   tcp
view    systemview    included   udp
view    systemview    included   snmp
 
####
# XenServer control domain does not support IPv6.
#
view    systemview    excluded   ipv6InterfaceTableLastChange
view    systemview    excluded   icmpStatsInErrors.ipv6
view    systemview    excluded   icmpStatsInMsgs.ipv6
view    systemview    excluded   icmpStatsOutErrors.ipv6
view    systemview    excluded   icmpStatsOutMsgs.ipv6
view    systemview    excluded   icmpMsgStatsInPkts.ipv6
view    systemview    excluded   icmpMsgStatsOutPkts.ipv6
 
####
# Finally, grant the group read-only access to the systemview view.
 
#       group          context sec.model sec.level prefix read       write  notif
access  notConfigGroup ""      any       noauth    exact  systemview none   none
 
###############################################################################
# System contact information
#
 
syslocation Unknown (edit /etc/snmp/snmpd.conf)
syscontact Root <root@localhost> (edit /etc/snmp/snmpd.conf)

Make the change on your smtpd.conf file on the two line (in red) you can find in the example above, of course you’ll need to change the IP range to match your network subnet.

Now you need to start the SNMP service using the following command line : service snmpd start

Finally, to enable the automatic start of the SNMP service at your XenServer startup, type : chkconfig snmpd on

Now I can begin to work on Cacti and try to monitor the host and the VMs (Next blog to come)