check_cfengine_lastseen

# This is a passive nagios checker for detecting if cf-agents
# have gone AWOL (Absent WithOut Leave) from the cf-server(s).
#
# It reads a file with hostnames (FQDN) that we care about
# being in touch, and needs the FQDN of the nagios server and the NSCA parameters
# (location of the nsca program and configuration file)
# Also it needs a comma separated list of cfengine servers that agents
# talk to. If the list is not complete there will be false positives.
#
# The script checks that the cf-agent of each host in the list
# has been in touch with at least one of the servers within the
# –warn number of minuts and sends an alarm if not.
#
# cf-key -s is used for checking when agents were last seen. Only version
# > 3.4.0 have the timestamp column so earlier versions will not work.
# Also, there is a bug in cf-key that truncates IPv6 addresses becaus most
# of the IPv6 addresses is longer than the address field width of the
# cf-keys -s output.
#
# See https://github.com/cfengine/core/pull/799 in order to know how to fix
# if you have IPv6 addresses. (Modify two lines of code and recompile cf-key. )
#
# The module needs passwordless login as root (and no interaction with host key
# acceptance ) via ssh to all servers in the –cfengine-servers list
# order to collect cf-key -s output. The path to ssh and cf-key
#
# The script warns, for each of the hosts in the list, if:
# * none of the DNS-registered PTR-records (IP4/IP6) of a hostnamie has been in
# touch with the server at all.
# * none of the DNS-registered PTR-records has been seen by any of the
# servers within —warn minutes.
#
# Hosts that should be ignored can be specified with the –filter-file option.