1SMOKEPING_MASTER_SLAVE(7)          SmokePing         SMOKEPING_MASTER_SLAVE(7)
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3
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NAME

6       smokeping_master_slave - How to run multiple distributed instances of
7       SmokePing
8

OVERVIEW

10       Normally smokeping probes run their tests from the host where smokeping
11       runs to some target host and monitor the latency of the connection
12       between the two.
13
14       The Master/Slave concept enables all smokeping probes to run remotely.
15       The use case for this is to measure the overall connectivity in a
16       network. If you are interested in checking that your central DNS server
17       or your file server works for everyone, you could setup several
18       smokeping instances checking up on on the two servers from multiple
19       locations within your network. With the Master/Slave smokeping
20       configuration this process becomes much simpler, as one smokeping
21       master server can control multiple slaves.
22
23       All monitoring data is stored and presented on the server, but
24       collected by the slaves. The slaves will also get their configuration
25       information from the master, so that you just have to maintain the
26       master server configuration file and the rest is taken care of
27       automatically.
28

DESCRIPTION

30   Architecture
31       The slaves communicate with the master smokeping server via the normal
32       smokeping web interface. On initial startup each slave connects to the
33       master server and asks for its assignments. When the slave has done a
34       round of probing it connects to the master again to deliver the
35       results.
36
37       If the assignment for a slave changes, the master will tell the slave
38       after the slave has delivered its results.
39
40       The master and the slaves sign their messages by supplying an HMAC-MD5
41       code (RFC 2104) of the message and a shared secret. Optionally the
42       whole communication can run over ssl.
43
44           [slave 1]     [slave 2]      [slave 3]
45               |             |              |
46               +-------+     |     +--------+
47                       |     |     |
48                       v     v     v
49                     +---------------+
50                     |    master     |
51                     +---------------+
52
53       The slave is a normal smokeping instance setup where the configuration
54       comes from the master instead of a local configuration file.  The slave
55       tries to contact the master server after every round of probing,
56       supplying its results.  If the master server can not be reached, the
57       results will be sent to the server together with the next round of
58       results.  Results will be stored in a file in Perl storable form so
59       that they survive a restart of the smokeping instance.
60
61   Master Configuration
62       To configure a master/slave setup, add a slaves section to your
63       smokeping configuration file. Each slave has a section in the slaves
64       part of the master configuration file. The section name must match the
65       hostname of the slave. If some configuration parameter must be set to a
66       special value for the slave, use an override section to configure this.
67
68       The slave names must be the names the hosts think they have, not their
69       outside hostnames or ip addresses or anything like that. When the slave
70       calls the master to get its config or report its measurements it will
71       tell the master its 'hostname'. This together with the shared secret is
72       used to authenticate and identify who is who.
73
74        *** Slaves ***
75        secrets=/etc/smokeping/slavesecrets.conf
76
77        +slave1
78        display_name=erul22
79        location=India
80        color=ff0000
81
82        ++override
83        Probes.FPing.binary = /usr/bin/fping
84        ...
85
86       Then in the targets section you can define slaves at every level. Again
87       the settings get inherited by lower order targets and can be
88       overwritten anywhere in the tree.
89
90       A slave will then get the appropriate configuration assigned by the
91       server.
92
93        *** Targets ***
94        slaves = slave1 slave2
95        ...
96        +dest1
97        slaves =
98        ...
99        +dest2
100        slaves = slave1
101        ...
102        +dest3
103        ...
104
105       The data from the slaves will be stored in TargetName~SlaveName.rrd. So
106       the example above would create the following files:
107
108        dest1.rrd
109        dest2.rrd
110        dest2~slave1.rrd
111        dest3.rrd
112        dest3~slave1.rrd
113        dest3~slave2.rrd
114
115       The slavesecrets.conf file contains a colon separated list of hostnames
116       and secrets.
117
118        host1:secret1
119        host2:secret2
120
121   Slave Configuration
122       A smokeping slave setup has no configuration file. It just needs to
123       know that it runs in slave-mode and its secret. The secret is stored in
124       a file for optimal protection. By default the persistent data cache
125       will be located in /tmp/smokeping.$USER.cache.
126
127        ./smokeping --master-url=http://smokeping/smokeping.cgi \
128                    --cache-dir=/var/smokeping/ \
129                    --shared-secret=/var/smokeping/secret.txt
130
131       The secret.txt file contains a single word, the secret of this slave.
132       It is NOT the same as the slavesecrets.conf file the master uses.
133

SECURITY CONSIDERATIONS

135       The master effectively has full access to slave hosts as the user
136       running the slave smokeping instance.  The configuration is transferred
137       as Perl code that is evaluated on the slave.  While this is done inside
138       a restricted "Safe" compartment, there are various ways that a
139       malicious master could embed arbitrary commands in the configuration
140       and get them to run when the slave probes its targets.
141
142       The strength of the shared secret is thus of paramount importance.
143       Brute forcing the secret would enable a man-in-the-middle to inject a
144       malicious new configuration and compromise the slave.
145
147       Copyright (c) 2007 by Tobias Oetiker, OETIKER+PARTNER AG. All right
148       reserved.
149

LICENSE

151       This program is free software; you can redistribute it and/or modify it
152       under the terms of the GNU General Public License as published by the
153       Free Software Foundation; either version 2 of the License, or (at your
154       option) any later version.
155
156       This program is distributed in the hope that it will be useful, but
157       WITHOUT ANY WARRANTY; without even the implied warranty of
158       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
159       General Public License for more details.
160
161       You should have received a copy of the GNU General Public License along
162       with this program; if not, write to the Free Software Foundation, Inc.,
163       675 Mass Ave, Cambridge, MA 02139, USA.
164

AUTHOR

166       Tobias Oetiker <tobi@oetiker.ch>
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1702.7.3                             2021-03-11         SMOKEPING_MASTER_SLAVE(7)
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