2013/03/12 [PERL WARNING] Use of uninitialized value $mtime_epoch in subtraction (-) at /opt/munin/www/cgi/munin-cgi-graph line 270.
2013/03/12 [PERL WARNING] Use of uninitialized value in concatenation (.) or string at /opt/munin/www/cgi/munin-cgi-graph line 237.
I think I have installed and completed the steps successfully. When I tried to view the image it shows below error in browser.LGC Sans Mono, Bitstream Vera Sans Mono,monospace' \ '--color' \ 'BACK#F0F0F0' \ '--color' \ 'FRAME#F0F0F0' \ '--color' \ 'CANVAS#FFFFFF' \ '--color' \ 'FONT#666666' \ '--color' \ 'AXIS#CFD6F8' \ '--color' \ 'ARROW#CFD6F8' \ '-W' \ 'Munin 2.0.1' \ 'DEF:aslab=/var/opt/munin/example.com/munin.example.com-meminfo_phisical-kernel-slab-g.rrd:42: MAX' \ 'DEF:islab=/var/opt/munin/example.com/munin.example.com-meminfo_phisical-kernel-slab-g.rrd:42: MIN' \ 'DEF:gslab=/var/opt/munin/example.com/munin.example.com-meminfo_phisical-kernel-slab-g.rrd:42: AVERAGE' \ 'DEF:akernel_stack=/var/opt/munin/example.com/munin.example.com-meminfo_phisical-kernel-kernel_stack-g.rrd:42: MAX' \ 'DEF:ikernel_stack=/var/opt/munin/example.com/munin.example.com-meminfo_phisical-kernel-kernel_stack-g.rrd:42: MIN' \ 'DEF:gkernel_stack=/var/opt/munin/example.com/munin.example.com-meminfo_phisical-kernel-kernel_stack-g.rrd:42: AVERAGE' \ 'CDEF:ckernel_stack=gkernel_stack' \ 'COMMENT: ' \ 'COMMENT: Cur\:' \ 'COMMENT: Min\:' \ 'COMMENT: Avg\:' \ 'COMMENT: Max\: \j' \ 'AREA:gkernel_stack#00CC00: Kernel stack ' \ 'GPRINT:ckernel_stack: LAST:%7.2lf%s' \ 'GPRINT:ikernel_stack: MIN:%7.2lf%s' \ 'GPRINT:gkernel_stack: AVERAGE:%7.2lf%s' \ 'GPRINT:akernel_stack: MAX:%7.2lf%s\j' \ 'CDEF:cslab=gslab' \ 'STACK:gslab#0066B3: Slab ' \ 'GPRINT:cslab: LAST:%7.2lf%s' \ 'GPRINT:islab: MIN:%7.2lf%s' \ 'GPRINT:gslab: AVERAGE:%7.2lf%s' \ 'GPRINT:aslab: MAX:%7.2lf%s\j' \ 'CDEF:ipostotal=ikernel_stack,islab, ADDNAN' \ 'CDEF:gpostotal=gkernel_stack,gslab, ADDNAN' \ 'CDEF:apostotal=akernel_stack,aslab, ADDNAN' \ 'LINE1:gpostotal#000000: Total ' \ 'GPRINT:gpostotal: LAST:%7.2lf%s' \ 'GPRINT:ipostotal: MIN:%7.2lf%s' \ 'GPRINT:gpostotal: AVERAGE:%7.2lf%s' \ 'GPRINT:apostotal: MAX:%7.2lf%s\j' \ 'COMMENT: Last update\: Tue Mar 12 05\:50\:03 2013\r' \ '--end' \ '1363063800' 2013/03/12 [INFO] Graphed service example.com;munin.example.com:meminfo_phisical.kernel (0.02 sec for 1 graphs) 2013/03/12 Munin-graph finished (0.02 sec) 2013/03/12 [WARNING] Could not draw graph "/var/opt/munin/cgi-tmp/munin-cgi-graph/example.com/munin.example.com/meminfo_phisical/kernel-day.png": /var/opt/munin/cgi-tmp/munin-cgi-graph/example.com/munin.example.com/meminfo_phisical/2013/03/12 [PERL WARNING] Use of uninitialized value $epoch in gmtime at /opt/munin/www/cgi/munin-cgi-graph line 283.2013/03/12 [PERL WARNING] Use of uninitialized value $mtime_epoch in modulus (%) at /opt/munin/www/cgi/munin-cgi-graph line 270.updatev returns a list of any and all consolidated data points (CDPs) written to disk as a result of the invocation of update.The values are indexed by timestamp (time_t), file, the update process will abort with an error message.Normally it will be numeric, but the data acquisition modules may impose their very own parsing of this parameter as long as the colon (:) remains the data source value separator.Update the database file demo2which expects data from a single data-source, three times.2013/03/12 [FATAL] Could not open image file "/var/opt/munin/cgi-tmp/munin-cgi-graph/example.com/munin.example.com/meminfo_phisical/kernel-day.png" for reading: No such file or directory Yep, this was the issue.I gave the following permission to the directory and the issue solved.Update 2014-04-10: I was getting these errors again on one of my VPS hosts. Because the servertime was running ahead the timestamps (the last update time) in the RRD files are in the future. Set the right time on the server if you have not done this yet.