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app-notes:cloud-router-alarms [2014/12/05 11:57] (current) |
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| + | ====== Cloud Router Alarms====== | ||
| + | Cloud Router shall send an alarm message via email, if one or more activated clients are offline. | ||
| + | |||
| + | ===== Prerequisites ===== | ||
| + | Make sure the hostname is configured correctly. If the FQDN is myserver.sub.example.com, ''/etc/hostname'' must contain a line like | ||
| + | <code - /etc/hostname> | ||
| + | myserver | ||
| + | </code> | ||
| + | and ''/etc/hosts'' must contain a line like | ||
| + | <code - /etc/hosts> | ||
| + | 1.2.3.4 myserver.sub.example.com myserver | ||
| + | </code> | ||
| + | Check correct configuration with ''hostname'' and ''hostname -f'' | ||
| + | |||
| + | Further, we need a Mail Transfer Agent (MTA) such as Exim 4 ((https://packages.debian.org/en/wheezy/exim4-daemon-light)) installed on our machine. For convenience reasons we will also install mailutils ((https://packages.debian.org/en/wheezy/mailutils)) so we can just call ''mail'' from the command line. | ||
| + | <code bash> | ||
| + | apt-get install exim4-daemon-light (or just default-mta) | ||
| + | dpkg-reconfigure exim4-config | ||
| + | apt-get install mailutils | ||
| + | </code> | ||
| + | |||
| + | Choose //internet site; mail is sent and received directly using SMTP// when configuring Exim. | ||
| + | |||
| + | Test in Shell | ||
| + | <code bash> | ||
| + | mail samuel.hess@netmodule.com | ||
| + | Cc: | ||
| + | Subject: Test | ||
| + | Some Body Text | ||
| + | Ctrl + D to send | ||
| + | </code> | ||
| + | |||
| + | |||
| + | |||
| + | ===== Implementation ===== | ||
| + | |||
| + | Cloud Router stores the current connections status for OpenVPN clients under ''/tmp/vpnportal/openvpn_clients'' | ||
| + | Make a file called ''activated'' with the activated clients | ||
| + | <code - activated> | ||
| + | OPENVPN_CLIENT_1 | ||
| + | OPENVPN_CLIENT_2 | ||
| + | OPENVPN_CLIENT_3 | ||
| + | OPENVPN_CLIENT_4 | ||
| + | OPENVPN_CLIENT_5 | ||
| + | OPENVPN_CLIENT_6 | ||
| + | OPENVPN_CLIENT_7 | ||
| + | OPENVPN_CLIENT_8 | ||
| + | OPENVPN_CLIENT_9 | ||
| + | OPENVPN_CLIENT_10 | ||
| + | </code> | ||
| + | |||
| + | Run a script like this: | ||
| + | <code bash surveyor.sh> | ||
| + | # This script checks every $interval if the activated clients are online. | ||
| + | # If one or more activated clients are offline, an e-mail alarm is sent. | ||
| + | activatedClients=/tmp/vpnportal/openvpn_clients/activated | ||
| + | connectedClients=/tmp/vpnportal/openvpn_clients/connected | ||
| + | interval=60 | ||
| + | recipient=alarms@netmodule.com | ||
| + | |||
| + | while true; do | ||
| + | while read client | ||
| + | do | ||
| + | grep -q $client $connectedClients | ||
| + | if [ $? -eq 0 ] | ||
| + | then | ||
| + | echo "$client is connected" > /dev/null | ||
| + | else | ||
| + | echo "$client is offline" | ||
| + | echo "$client is offline" >> message2 | ||
| + | fi | ||
| + | done < $activatedClients | ||
| + | if [ -f message2 ] | ||
| + | then | ||
| + | echo "sending alarm message" | ||
| + | echo "This alarm message is coming from $(hostname -f) since one or more activated clients are offline:" > message1 | ||
| + | cat message1 message2 | mail -s "Cloud Router Alarm: Client(s) offline" recipient | ||
| + | rm message* | ||
| + | fi | ||
| + | sleep $interval | ||
| + | done | ||
| + | </code> | ||