Difference between revisions of "Cluster: Ganglia README"

Revision as of 15:33, 4 October 2020

Add a server to ganglia monitoring

Gmond (Deamon Ganglia Monitoring): This service will retrieve some information about the node to be monitored.

Gmetad (Ganglia Meta Daemon): Gmetad will collect data from all gmonds. Including gmond which is installed on the client. Gmetad only needs to be installed on the server side only.

RRD (Round Robin Database): Used to store data on ganglia.

Ganglia Web: A web interface for displaying data graph displays and matrices from rrd tools.

Copied from this article: https://medium.com/@cakhanif/setup-real-time-monitoring-using-ganglia-on-centos-7-45706a49ea89

Instructions for installing Ganglia on client node (Centos):

On Client machine:

1. yum install ganglia-gmond

2. In /etc/ganglia/gmond.conf set udp send channel to host=hopper.cluster.earlham.edu. See lovelace’s config of gmond as a reference.

3. yum restart gmond

Name
ganglia - distributed monitoring system

Version
ganglia 3.1.2

The latest version of this software and document will always be found at
http://ganglia.sourceforge.net/. You are currently reading $Revision:
1705 $ of this document.

Synopsis
______ ___
/ ____/___ _____ ____ _/ (_)___ _
/ / __/ __ `/ __ \/ __ `/ / / __ `/
/ /_/ / /_/ / / / / /_/ / / / /_/ /
\____/\__,_/_/ /_/\__, /_/_/\__,_/
/____/ Distributed Monitoring System

Ganglia is a scalable distributed monitoring system for high-performance
computing systems such as clusters and Grids. It is based on a
hierarchical design targeted at federations of clusters. It relies on a
multicast-based listen/announce protocol to monitor state within
clusters and uses a tree of point-to-point connections amongst
representative cluster nodes to federate clusters and aggregate their
state. It leverages widely used technologies such as XML for data
representation, XDR for compact, portable data transport, and RRDtool
for data storage and visualization. It uses carefully engineered data
structures and algorithms to achieve very low per-node overheads and
high concurrency. The implementation is robust, has been ported to an
extensive set of operating systems and processor architectures, and is
currently in use on over 500 clusters around the world. It has been used
to link clusters across university campuses and around the world and can
scale to handle clusters with 2000 nodes.

The ganglia system is comprised of two unique daemons, a PHP-based web
frontend and a few other small utility programs.

Ganglia Monitoring Daemon (gmond)
Gmond is a multi-threaded daemon which runs on each cluster node you
want to monitor. Installation is easy. You don't have to have a
common NFS filesystem or a database backend, install special
accounts, maintain configuration files or other annoying hassles.

Gmond has four main responsibilities: monitor changes in host state,
announce relevant changes, listen to the state of all other ganglia
nodes via a unicast or multicast channel and answer requests for an
XML description of the cluster state.

Each gmond transmits in information in two different ways:
unicasting/multicasting host state in external data representation
(XDR) format using UDP messages or sending XML over a TCP
connection.

Ganglia Meta Daemon (gmetad)
Federation in Ganglia is achieved using a tree of point-to-point
connections amongst representative cluster nodes to aggregate the
state of multiple clusters. At each node in the tree, a Ganglia Meta
Daemon ("gmetad") periodically polls a collection of child data
sources, parses the collected XML, saves all numeric, volatile
metrics to round-robin databases and exports the aggregated XML over
a TCP sockets to clients. Data sources may be either "gmond"
daemons, representing specific clusters, or other "gmetad" daemons,
representing sets of clusters. Data sources use source IP addresses
for access control and can be specified using multiple IP addresses
for failover. The latter capability is natural for aggregating data
from clusters since each "gmond" daemon contains the entire state of
its cluster.

Ganglia PHP Web Frontend
The Ganglia web frontend provides a view of the gathered information
via real-time dynamic web pages. Most importantly, it displays
Ganglia data in a meaningful way for system administrators and
computer users. Although the web frontend to ganglia started as a
simple HTML view of the XML tree, it has evolved into a system that
keeps a colorful history of all collected data.

The Ganglia web frontend caters to system administrators and users.
For example, one can view the CPU utilization over the past hour,
day, week, month, or year. The web frontend shows similar graphs for
Memory usage, disk usage, network statistics, number of running
processes, and all other Ganglia metrics.

The web frontend depends on the existence of the "gmetad" which
provides it with data from several Ganglia sources. Specifically,
the web frontend will open the local port 8651 (by default) and
expects to receive a Ganglia XML tree. The web pages themselves are
highly dynamic; any change to the Ganglia data appears immediately
on the site. This behavior leads to a very responsive site, but
requires that the full XML tree be parsed on every page access.
Therefore, the Ganglia web frontend should run on a fairly powerful,
dedicated machine if it presents a large amount of data.

The Ganglia web frontend is written in the PHP scripting language,
and uses graphs generated by "gmetad" to display history
information. It has been tested on many flavours of Unix (primarily
Linux) with the Apache webserver and the PHP module (4.1 or later).

Installation
The latest version of all ganglia software can always be downloaded from
http://ganglia.info/

Ganglia runs on Linux (i386, ia64, sparc, alpha, powerpc, m68k, mips,
arm, hppa, s390), FreeBSD, NetBSD, OpenBSD, DragonflyBSD, MacOS X,
Solaris, AIX, IRIX, Tru64, HPUX and Windows NT/XP/2000/2003/2008 making
it as portable as it is scalable.

Monitoring Core Installation
If you use the Linux RPMs provided on the ganglia web site, you can skip
to the end of this section.

Ganglia uses the GNU autoconf so compilation and installation of the
monitoring core is basically

% ./configure
% make
% make install

but there are some issues that you need to take a look at first.

Kernel multicast support
If you use the ganglia multicast support, you must have a kernel
that supports multicast. The vast majority of machines have
multicast support by default. If you have problems with ganglia this
is a core issue.

Gmetad is not installed by default
Since "gmetad" relies on the Round-Robin Database Tool ( see
http://www.rrdtool.org/ ) it will not be compiled unless you
explicit request it by using a --with-gmetad flag.

% ./configure --with-gmetad

The configure script will fail if it cannot find the rrdtool library
and header files. By default, it expects to find them at
/usr/include/rrd.h and /usr/lib/librrd.so. If you installed them in
different locations then you need to instruct configure where to
find them using:

% ./configure --with-librrd=/rrd/path --with-gmetad

Of course, you need to substitute "/rrd/path" with the real location
of the rrd tool directory where the header file can be located
inside an include subdirectory and the library can be located inside
a lib subdirectory. As an alternative you could set "-L" in LDFLAGS,
and "-I" in CFLAGS and CPPFLAGS for the library path and the header
path respectively.

AIX should not be compiled with shared libraries
You must add the "--disable-shared" configure flags if you are
running on AIX. For more details refer to the README.AIX file

% ./configure --disable-shared

Solaris dependencies could be problematic
Not really a Solaris specific problem, but since Solaris has several
different package repositories, all of them unofficial, it is
difficult to be sure that all possible permutations have been
confirmed to work reliably.

Be sure to have all dependencies covered, as explained in the
INSTALL file and to use GNU make and a gcc compiler that builds
32bit binaries with all other libraries matching that ISA.

When in doubt, build the problematic dependency from source and
remember to distribute it together with your ganglia build as
everything is dynamically linked by default.

Be particularly careful with libConfuse, especially if using the old
2.5 version. LibConfuse 2.5 is known to be incorrectly packaged and
to compile by default as a static library which will fail to link
with ganglia.

Propietary *NIX systems might not work at all
The good news is that the libmetrics code that used to work before
3.1 is still most likely working fine and so there is nothing
fundamentally broken about it.

But the bad news is that in order to add the dynamic metric
functionality, the build system and the way gmond used to locate its
metrics had to be changed significantly. Therefore getting gmond to
build and work again required fixes to be implemented for all
platforms.

Since none of the developers had access to HPUX, IRIX, Tru64
(OSF/1), or Darwin (MacOS X) those platforms might not be able to
build or run a 3.1 gmond yet. If you have access to any of these
platforms and want to run ganglia 3.1, feel free to drop by the
ganglia-developers list with suggestions, or even better patches.

GEXEC confusion
GEXEC is a scalable cluster remote execution system which provides
fast, RSA authenticated remote execution of parallel and distributed
jobs. It provides transparent forwarding of stdin, stdout, stderr,
and signals to and from remote processes, provides local environment
propagation, and is designed to be robust and to scale to systems
over 1000 nodes. Internally, GEXEC operates by building an n-ary
tree of TCP sockets and threads between gexec daemons and
propagating control information up and down the tree. By using
hierarchical control, GEXEC distributes both the work and resource
usage associated with massive amounts of parallelism across multiple
nodes, thereby eliminating problems associated with single node
resource limits (e.g., limits on the number of file descriptors on
front-end nodes). (from http://www.theether.org/gexec )

"gexec" is a great cluster execution tool but integrating it with
ganglia is a bit clumsy. GEXEC can run standalone without access to
a ganglia "gmond". In standalone mode gexec will use the hosts
listed in your GEXEC_SVRS variable to run on. For example, say I
want to run "hostname" on three machines in my cluster: "host1",
"host2" and "host3". I use the following command line.

% GEXEC_SVRS="host1 host2 host3" gexec -n 3 hostname

and gexec would build an n-ary tree (binary tree by default) of TCP
sockets to those machines and run the command "hostname"

As an added feature, you can have "gexec" pull a host list from a
locally running gmond and use that as the host list instead of
GEXEC_SVRS. The list is load balanced and "gexec" will start the job
on the *n* least-loaded machines.

For example..

% gexec -n 5 hostname

will run the command "hostname" on the five least-loaded machines in
a cluster.

To turn on the "gexec" feature in ganglia you must configure ganglia
with the "--enable-gexec" flag

% ./configure --enable-gexec

Enabling "gexec" means that by default any host running gmond will
send a special message announcing that gexec is installed on it and
open for requests.

Now the question is, what if I don't want gexec to run on every host
in my cluster? For example, you may not want to have "gexec" run
jobs on your cluster frontend nodes.

You simply add the following line to your "gmond" configuration file
("/etc/ganglia/gmond.conf" by default)

no_gexec on

Simple huh? I know the configuration file option, "no_gexec", seems
crazy (and it is). Why have an option that says "yes to no gexec"?
The early versions of gmond didn't use a configuration file but
instead commandline options. One of the commandline options was
simply "--no-gexec" and the default was to announce gexec as on.

Once you have successfully run

% ./configure <options>
% make
% make install

you should find the following files installed in "/usr" (by default).

/usr/bin/gstat
/usr/bin/gmetric
/usr/sbin/gmond
/usr/sbin/gmetad

If you installed ganglia using RPMs then these files will be installed
when you install the RPM. The RPM is installed simply by running

% rpm -Uvh ganglia-gmond-3.1.2.i386.rpm
% rpm -Uvh ganglia-gmetad-3.1.2.i386.rpm

Once you have the necessary binaries installed, you can test your
installation by running

% ./gmond

This will start the ganglia monitoring daemon. You should then be able
to run

% telnet localhost 8649

And get an XML description of the state of your machine (and any other
hosts running gmond at the time).

If you are installing by source on Linux, scripts are provided to start
"gmetad" and "gmond" at system startup. They are easy to install from
the source root.

% cp ./gmond/gmond.init /etc/rc.d/init.d/gmond
% chkconfig --add gmond
% chkconfig --list gmond
gmond 0:off 1:off 2:on 3:on 4:on 5:on 6:off
% /etc/rc.d/init.d/gmond start
Starting GANGLIA gmond: [ OK ]

Repeat this step with gmetad.

PHP Web Frontend Installation
1. The ./web directory of the ganglia distribution contains all the
necessary PHP files for running your web frontend. Copy those files
to "/var/www/html", however look for the variable "DocumentRoot" in
your Apache configuration files to be sure. All the PHP script files
use relative URLs in their links, so you may place the "ganglia/"
directory anywhere convenient.

2. Ensure your webserver understands how to process PHP script files.
Currently, the web frontend contains certain php language that
requires PHP version 4 or greater. Processing PHP script files
usually requires a webserver module, such as the "mod_php" for the
popular Apache webserver. In RedHat Linux, the RPM package that
provides this module is called simply "php".

For Apache, "mod_php" module must be enabled. The following lines
should appear somewhere in Apache's *conf files. This example
applies to RedHat and Mandrake Linux. The actual filenames may vary
on your system. If you installed the php module using an RPM
package, this work will have been done automatically.

<IfDefine HAVE_PHP4>
LoadModule php4_module extramodules/libphp4.so
AddModule mod_php4.c
</IfDefine>

AddType application/x-httpd-php .php .php4 .php3 .phtml
AddType application/x-httpd-php-source .phps

3. The webfrontend requires the existance of the gmetad package on the
webserver. Follow the installation instructions on the gmetad page.
Specifically, the webfrontend requires the rrdtool and the "rrds/"
directory from gmetad. If you are a power user, you may use NFS to
simulate the local existance of the rrds.

4. Test your installation. Visit the URL:

http://localhost/ganglia/

With a web-browser, where localhost is the address of your
webserver.

Installation of the web frontend is simplified on Linux by using rpm.

% rpm -Uvh ganglia-web-3.1.2-1.i386.rpm
Preparing... ########################################### [100%]
1:ganglia-web ########################################### [100%]

Configuration
Gmond Configuration
The configuration file format has changed between gmond version 2.5.x
and version 3.x. The change was necessary in order to allow more complex
configuration options.

Gmond has a default configuration it will use if it does not find the
default configuration file /etc/ganglia/gmond.conf. To see the default
configuration simply run the command:

% gmond --default_config

and gmond will output its default configuration to stdout. This default
configuration can serve as a good starting place for building a more
custom configuration.

% gmond --default_config > gmond.conf

would create a file gmond.conf which you can then edit to taste and copy
to /etc/ganglia/gmond.conf or elsewhere.

To start gmond with a configuration file other then
/etc/ganglia/gmond.conf, simply specify the configuration file location
by running

% gmond --config /my/ganglia/configs/custom.conf

If you want to convert a 2.5.x configuration file to 3.x file format,
run the following command

% gmond --convert ./old_25_config.conf

and gmond with output the equivalent 3.x configuration file to stdout.
You can then redirect that output to a new configuration file which can
serve as a starting point for your configuration.

% gmond --convert ./old_25_config.conf > ./new_26_config.conf

For details about gmond configuration options, simply run

% man gmond.conf

for a complete listing of options with detailed explanations.

Gmetad Configuration
The behavior of the Ganglia Meta Daemon is completely controlled by a
single configuration file which is by default
"/etc/ganglia/gmetad.conf". For gmetad to do anything useful you much
specify at least one "data_source" in the configuration. The format of
the data_source line is as follows

data_source "Cluster A" 127.0.0.1 1.2.3.4:8655 1.2.3.5:8625
data_source "Cluster B" 1.2.4.4:8655

In this example, there are two unique data sources: "Cluster A" and
"Cluster B". The Cluster A data source has three redundant sources. If
gmetad cannot pull the data from the first source, it will continue
trying the other sources in order.

If you do not specify a port number, gmetad will assume the default
ganglia port which is 8649 (U*N*I*X on a phone key pad)

For a sample gmetad configuration file with comments, look at the
gmetad.conf file provided as part of the distribution package in the
gmetad directory

"gmetad" has a "--conf" option to allow you to specify alternate
configuration files

% ./gmetad -conf=/tmp/my_custom_config.conf

PHP Web Frontend Configuration
Most configuration parameters reside in the "ganglia/conf.php" file.
Here you may alter the template, gmetad location, RRDtool location, and
set the default time range and metrics for graphs.

The static portions of the Ganglia website are themable. This means you
can alter elements such as section lables, some links, and images to
suit your individual tastes and environment. The "template_name"
variable names a directory containing the current theme. Ganglia uses
TemplatePower to implement themes. A user-defined skin must conform to
the template interface as defined by the default theme. Essentially, the
variable names and START/END blocks in a custom theme must remain the
same as the default, but all other HTML elements may be changed.

Other configuration variables in "conf.php" specify the location of
gmetad's files, and where to find the rrdtool program. These locations
need only be changed if you do not run gmetad on the webserver.
Otherwise the default locations should work fine. The "default_range"
variable specifies what range of time to show on the graphs by default,
with possible values of hour, day, week, month, year. The
"default_metric" parameter specifies which metric to show on the cluster
view page by default.

Commandline Tools
There are two commandline tools that work with "gmond" to add custom
metrics and query the current state of a cluster: "gmetric" and "gstat"
respectively.

Gmetric
The Ganglia Metric Tool (gmetric) allows you to easily monitor any
arbitrary host metrics that you like expanding on the core metrics that
gmond measures by default.

If you want help with the gmetric sytax, simply use the "help"
commandline option

% gmetric --help
gmetric 3.1.2

Purpose:
The Ganglia Metric Client (gmetric) announces a metric
on the list of defined send channels defined in a configuration file

Usage: gmetric [OPTIONS]...

-h, --help Print help and exit
-V, --version Print version and exit
-c, --conf=STRING The configuration file to use for finding send channels
(default=`/etc/ganglia/gmond.conf')
-n, --name=STRING Name of the metric
-v, --value=STRING Value of the metric
-t, --type=STRING Either
string|int8|uint8|int16|uint16|int32|uint32|float|double
-u, --units=STRING Unit of measure for the value e.g. Kilobytes, Celcius
(default=`')
-s, --slope=STRING Either zero|positive|negative|both (default=`both')
-x, --tmax=INT The maximum time in seconds between gmetric calls
(default=`60')
-d, --dmax=INT The lifetime in seconds of this metric (default=`0')
-S, --spoof=STRING IP address and name of host/device (colon separated) we
are spoofing (default='')
-H, --heartbeat spoof a heartbeat message (use with spoof option)

Gmetric sends the metric specified on the commandline to all
udp_send_channels specified in the configuration file
/etc/ganglia/gmond.conf by default. If you want to send metric to
alternate udp_send_channels, you can specify a different configuration
file as such:

% gmetric --conf=./custom.conf -n "wow" -v "it works" -t "string"

All metrics in ganglia have a name, value, type and optionally units.
For example, say I wanted to measure the temperature of my CPU
(something gmond doesn't do by default) then I could send this metric
with name="temperature", value="63", type="int16" and units="Celcius".

Assume I have a program called "cputemp" which outputs in text the
temperature of the CPU

% cputemp
63

I could easily send this data to all listening gmonds by running

% gmetric --name temperature --value `cputemp` --type int16 --units Celcius

Check the exit value of gmetric to see if it successfully sent the data:
0 on success and -1 on failure.

To constantly sample this temperature metric, you just need too add this
command to your cron table.

Gstat
The Ganglia Cluster Status Tool (gstat) is a commandline utility that
allows you to get status report for your cluster.

To get help with the commandline options, simply pass "gstat" the
"--help" option

% gstat --help
gstat 3.1.2

Purpose:
The Ganglia Status Client (gstat) connects with a
Ganglia Monitoring Daemon (gmond) and output a load-balanced list
of cluster hosts

Usage: gstat [OPTIONS]...
-h --help Print help and exit
-V --version Print version and exit
-a --all List all hosts. Not just hosts running gexec (default=off)
-d --dead Print only the hosts which are dead (default=off)
-m --mpifile Print a load-balanced mpifile (default=off)
-1 --single_line Print host and information all on one line (default=off)
-l --list Print ONLY the host list (default=off)
-n --numeric Print numeric addresses instead of hostnames (default=off)
-iSTRING --gmond_ip=STRING Specify the ip address of the gmond to query (default='127.0.0.1')
-pINT --gmond_port=INT Specify the gmond port to query (default=8649)

Note: gstat with no option will only show gexec-enabled hosts. To see
all hosts that are UP (regardless of their gexec state) you need to add
the --all flag.

% gstat --all

Extending Ganglia through metric modules
There are currently two ways in which metric modules can be written and
plugged into Gmond in order to extend the types of metrics that Ganglia
is able to monitor. As of Ganglia 3.1, a pluggable interface has been
added to allow the Gmond metric gathering agent to collect any type of
metric that can be acquired through programatic means. The primary
metric module interface is C with a secondary python interface. This
means that pluggable modules can either be written and compiled into
dynamically loadable C based language modules or written and deployed as
python pluggable modules.

The basic steps when writting a pluggable module either in C or in
python, is as follows:

1. Create a module definition structure that contains callback data and
metric information
2. Implement 3 callback functions that will serve as the links between
the Gmond metric gathering agent and the metric module. These callback
functions include module initialization, metric handler and module
cleanup.

There are simple metric module examples for both a C based and a python
based module under the gmond/modules and gmond/python_modules source
code sub-trees. Please see these module examples for more details.

Frequently Asked Questions (FAQ)
What metrics does ganglia collect on platform x?
To see a complete list of the metrics that a particular gmond
supports, run the command:

% gmond -m

and gmond will output all the metrics that it is capable of
collecting and sending.

This table describes all the metrics that ganglia collects and shows
what platforms the metric are supported on. (The following table is
only partially complete).

Metric Name Description Platforms
-----------------------------------------------------------------------
boottime System boot timestamp l,f
bread_sec
bwrite_sec
bytes_in Number of bytes in per second l,f
bytes_out Number of bytes out per second l,f
cpu_aidle Percent of time since boot idle CPU l
cpu_arm
cpu_avm
cpu_idle Percent CPU idle l,f
cpu_intr
cpu_nice Percent CPU nice l,f
cpu_num Number of CPUs l,f
cpu_rm
cpu_speed Speed in MHz of CPU l,f
cpu_ssys
cpu_system Percent CPU system l,f
cpu_user Percent CPU user l,f
cpu_vm
cpu_wait
cpu_wio
disk_free Total free disk space l,f
disk_total Total available disk space l,f
load_fifteen Fifteen minute load average l,f
load_five Five minute load average l,f
load_one One minute load average l,f
location GPS coordinates for host e
lread_sec
lwrite_sec
machine_type
mem_buffers Amount of buffered memory l,f
mem_cached Amount of cached memory l,f
mem_free Amount of available memory l,f
mem_shared Amount of shared memory l,f
mem_total Amount of available memory l,f
mtu Network maximum transmission unit l,f
os_name Operating system name l,f
os_release Operating system release (version) l,f
part_max_used Maximum percent used for all partitions l,f
phread_sec
phwrite_sec
pkts_in Packets in per second l,f
pkts_out Packets out per second l,f
proc_run Total number of running processes l,f
proc_total Total number of processes l,f
rcache
swap_free Amount of available swap memory l,f
swap_total Total amount of swap memory l,f
sys_clock Current time on host l,f
wcache

Platform key:
l = Linux, f = FreeBSD, a = AIX, c = Cygwin
m = MacOS, i = IRIX, h = HPUX, t = Tru64
e = Every Platform

If you are interested in how the metrics are collected, just take a
look in directory "./libmetrics" in the source distribution. There
is a directory for each platform that is supported.

What does the error "Process XML (x): XML_ParseBuffer() error at line x:
not well-formed"
This is an error that occurs when a ganglia components reads data
from another ganglia component and finds that the XML is not
well-formed. The most common time this is a problem is when the PHP
web frontend tries to read the XML stream from gmetad.

To troubleshoot this problem, capture an XML from the ganglia
component in question (gmetad/gmond). This is easy to do if you have
telnet installed. Simply login to the machine running the component
and run.

% telnet localhost 8651

By default, gmetad exports its XML on port 8651 and gmond exports
its XML on port 8649. Modify the port number above to suite your
configuration.

When you connect to the port you should get an XML stream. If not,
look in the process table on the machine to ensure that the
component is actually running.

Once you are getting an XML stream, capture it to a file by running.

% telnet localhost 8651 > XML.txt
Connection closed by foreign host.

If you open the file "XML.txt", you will see the captured XML
stream. You will need to remove the first three lines of the
"XML.txt" which will read...

Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

Those lines are output from "telnet" and not the ganglia component
(I wish telnet would send those messages to "stderr" but they are
send to "stdout").

There are many ways that XML can be misformed. The great tool for
validating XML is "xmllint". "xmllint" will read the file and find
the line containing the error.

% xmllint --valid --noout XML.txt

will read your captured XML stream, validate it against the ganglia
DTD and check that it is well-formed XML. "xmllint" will quiet exit
if there are no errors. If there are errors they will be reported
with line numbers. For example...

/tmp/XML.txt:3393: error: Opening and ending tag mismatch: HOST and CLUSTER
</CLUSTER>
^
/tmp/XML.txt:3394: error: Opening and ending tag mismatch: CLUSTER and GANGLIA_XML
</GANGLIA_XML>
^
/tmp/XML.txt:3395: error: Premature end of data in tag GANGLIA_XML

If you get errors, open "XML.txt" and go to the line numbers in
question. See if you can understand based on your configuration how
these errors could occur. If you cannot fix the problem yourself,
please email your "XML.txt" and output from "xmllint" to
"ganglia-developers@lists.sourceforge.net". Please include
information about the version of each component in question along
with the operating system they are running on. The more details we
have about your configuration the more likely it is we will be able
to help you. Also, all mailing to "ganglia-developers" is archiving
and available to read on the web. You may want to modify "XML.txt"
to remove any sensitive information.

How do I remove a host from the list?
A common problem that people have is not being able to remove a host
from the ganglia web frontend.

Here is a common scenario

1. All hosts in a cluster are send on the ganglia udp_send_channels.
2. One of the hosts fails or is moved for whatever reason.
3. All the hosts in the cluster report that the host is "dead" or
"expired".
4. The sysadmin wants to removed this host from the "dead" list.

Unfortunately there is currently no nice way to remove a single dead
host from the list. All data in gmond is soft state so you will need
to restart all gmond and gmetad processes. It is important to note
that ALL dead hosts will be flushed from the record by restarting
the processes (since they have to hear the host at least once to
know it is expired).

If you add the line

globals {
host_dmax = 3600
}

then hosts will be removed from host tables when they haven't been
heard from in 3600 seconds. See "man gmond.conf" for details.

How good is Solaris, IRIX, Tru64 support?
Here is an email from Steve Wagner about the state of the ganglia on
Solaris, IRIX and Tru64. Steve is to thank for porting ganglia to
Solaris and Tru64. He also helped with the IRIX port.

State of the IRIX port:

* CPU percentage stuff hasn't improved despite my efforts. I fear there
may be a flaw in the way I'm summing counters for all the CPUs.
* Auto-detection of network interfaces apparently segfaults.
* Memory and load reporting appear to be running properly.
* CPU speed is not being reported properly on multi-proc machines.
* Total/running processes are not reported.
* gmetad untested.
* Monitoring core apparently stable in foreground, background being tested
(had a segfault earlier).

State of the Tru64 port:

* CPU percentage stuff here works perfectly.
* Memory and swap usage stats are suspected to be inaccurate.
* Total/running processes are not reported.
* gmetad untested.
* Monitoring core apparently stable in foreground and background.

State of the Solaris port:
* CPU percentages are slightly off, but correct enough for trending
purposes.
* Load, ncpus, CPU speed, breads/writes, lreads/writes, phreads/writes,
and rcache/wcache are all accurate.
* Memory/swap statistics are suspiciously flat, but local stats bear
this out (and they *are* being updated) so I haven't investigated
further.
* Total processes are counted, but not running ones.
* gmetad appears stable

Anyway, all three ports I've been messing with are usable and fairly
stable. Although there are areas for improvement I think we really can't
keep hogging all this good stuff - what I'm looking at is ready for
release.

Where are the debian packages?
Debian packages for 2.5 are available from the main Debian archive
for all releases.

There was never an oficial Debian package for 3.0 but packages for
3.1 are available from Debian experimental and will be available in
the Debian archive as soon as they are stabilized.

If you are interested on using them (and help them stabilize) you
can get them from:

http://packages.debian.org/experimental/ganglia-monitor

How should I configure multihomed machines?
Here is an email that Matt Massie sent to a user having problems
with multihomed machines

i need to add a section in the documentation talking about this since it
seems to be a common question.

when you use...

mcast_if eth1

.. in /etc/ganglia/gmond.conf that tells gmond to send its data out the "eth1"
network interface but that doesn't necessarily mean that the source
address of the packets will match the "eth1" interface. to make sure that
data sent out eth1 has the correct source address run the following...

% route add -host 239.2.11.71 dev eth1

... before starting gmond. that should do the trick for you.

-matt

> I have seen some post related to some issues
> with gmond + multicast running on a dual nic
> frontend.
>
> Currently I am experiencing a weird behavior
>
> I have the following setup:
>
> -----------------------
> | web server + gmetad |
> -----------------------
> |
> |
> |
> ----------------------
> | eth0 A.B.C.112 |
> | |
> | Frontend + gmond |
> | |
> | eth1 192.168.100.1 |
> ----------------------
> |
> |
>
> 26 nodes each
> gmond
>
> In the frontend /etc/gmond.conf I have the
> following statement: mcast_if eth1
>
> The 26 nodes are correctly reported.
>
> However the Frontend is never reported.
>
> I am running iptables on the Frontend, and I am seing
> things like:
>
> INPUT packet died: IN=eth1 OUT= MAC= SRC=A.B.C.112 DST=239.2.11.71
> LEN=36 TOS=0x00 PREC=0x00 TTL=1 ID=53740 DF PROTO=UDP SPT=41608 DPT=8649
> LEN=16
>
> I would have expected the source to be 192.168.100.1 with mcast_if eth1
>
> Any idea ?

How should I configure my Cisco Catalyst Switches?
Perhaps information regarding gmond on networks set up through cisco
catalyst switches should be mentioned in the ganglia documentation.
I think by default multicast traffic on the catalyst will flood all
devices unless configured properly. Here is a relavent snipet from a
message forum, with a link to cisco document.

If what you are trying to do, is minimizing the impact on your
network due to a multicast application, this link may describe what
you want to do: http://www.cisco.com/warp/public/473/38.html

We set up our switches according to this after a consultant came in
and installed an application multicasting several hundred packets
per second. This made the network functional again.

Getting Support
The tired and thirsty prospector threw himself down at the edge of the
watering hole and started to drink. But then he looked around and saw
skulls and bones everywhere. "Uh-oh," he thought. "This watering hole
is reserved for skeletons." --Jack Handey

There are three mailing lists available to you: "ganglia-general",
"ganglia-developers" and "ganglia-announce". You can join these lists or
read their archives by visiting
https://sourceforge.net/mail/?group_id=43021

"All of the ganglia mailing lists are closed". That means that in order
to post to the lists, you must be subscribed to the list. We're sorry
for the inconvenience however it is very easy to subscribe and
unsubscribe from the lists. We had to close the mailing lists because of
SPAM problems.

When you need help please follow these steps until your problem is
resolved.

1. completely read the documentation

2. check the "ganglia-general" archive to see if other people have had
the same problem

3. post your support request to the "ganglia-general" mailing list

4. check the "ganglia-developers" archive

5. post your question to the "ganglia-developers" list

please send all bugs, patches, and feature requests to the
"ganglia-developers" list after you have checked the
"ganglia-developers" archive to see if the question has already been
asked and answered.

Authors
The Ganglia Development Team...

Bas van der Vlies basv Developer basv at users.sourceforge.net
Neil T. Spring bluehal Developer bluehal at users.sourceforge.net
Brooks Davis brooks_en_davis Developer brooks_en_davis at users.sourceforge.net
Eric Fraser fraze Developer fraze at users.sourceforge.net
greg bruno gregbruno Developer gregbruno at users.sourceforge.net
Jeff Layton laytonjb Developer laytonjb at users.sourceforge.net
Doc Schneider maddocbuddha Developer maddocbuddha at users.sourceforge.net
Mason Katz masonkatz Developer masonkatz at users.sourceforge.net
Mike Howard mhoward Developer mhoward at users.sourceforge.net
Matt Massie massie Project Admin massie at users.sourceforge.net
Oliver Mössinger olivpass Developer olivpass at users.sourceforge.net
Preston Smith pmsmith Developer pmsmith at users.sourceforge.net
Federico David Sacerdoti sacerdoti Developer sacerdoti at users.sourceforge.net
Tim Cera timcera Developer timcera at users.sourceforge.net
Mathew Benson wintermute11 Developer wintermute11 at users.sourceforge.net
Brad Nicholes bnicholes Developer bnicholes at users.sourceforge.net
Carlo Arenas carenas Developer carenas at users.sourceforge.net

Contributors
There have been dozens of contributors who have provided patches and
helpful bug reports. We need to list them here later.

Difference between revisions of "Cluster: Ganglia README"

Revision as of 15:33, 4 October 2020

Add a server to ganglia monitoring

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@@ Line 1: / Line 1: @@
+== Add a server to ganglia monitoring ==
+Gmond (Deamon Ganglia Monitoring): This service will retrieve some information about the node to be monitored.
+Gmetad (Ganglia Meta Daemon): Gmetad will collect data from all gmonds. Including gmond which is installed on the client. Gmetad only needs to be installed on the server side only.
+RRD (Round Robin Database): Used to store data on ganglia.
+Ganglia Web: A web interface for displaying data graph displays and matrices from rrd tools.
+Copied from this article: https://medium.com/@cakhanif/setup-real-time-monitoring-using-ganglia-on-centos-7-45706a49ea89
+Instructions for installing Ganglia on client node (Centos):
+On Client machine:
+.	yum install ganglia-gmond
+.	In /etc/ganglia/gmond.conf set udp send channel to host=hopper.cluster.earlham.edu. See lovelace’s config of gmond as a reference.
+.	yum restart gmond
 <pre><nowiki>