More advanced triggers
by Andrea Vacche, Patrik Uytterhoeven, Rihards Olups
Zabbix: Enterprise Network Monitoring Made Easy
- Zabbix: Enterprise Network Monitoring Made Easy
- Table of Contents
- Zabbix: Enterprise Network Monitoring Made Easy
- Zabbix: Enterprise Network Monitoring Made Easy
- Credits
- Preface
- I. Module 1
- 1. Getting Started with Zabbix
- The first steps in monitoring
- Zabbix features and architecture
- Installation
- Summary
- 2. Getting Your First Notification
- 3. Monitoring with Zabbix Agents and Basic Protocols
- 4. Monitoring SNMP Devices
- 5. Managing Hosts, Users, and Permissions
- 6. Detecting Problems with Triggers
- 7. Acting upon Monitored Conditions
- 8. Simplifying Complex Configurations with Templates
- 9. Visualizing Data with Graphs and Maps
- 10. Visualizing Data with Screens and Slideshows
- 11. Advanced Item Monitoring
- 12. Automating Configuration
- 13. Monitoring Web Pages
- 14. Monitoring Windows
- 15. High-Level Business Service Monitoring
- 16. Monitoring IPMI Devices
- 17. Monitoring Java Applications
- 18. Monitoring VMware
- 19. Using Proxies to Monitor Remote Locations
- 20. Encrypting Zabbix Traffic
- 21. Working Closely with Data
- 22. Zabbix Maintenance
- A. Troubleshooting
- B. Being Part of the Community
- 1. Getting Started with Zabbix
- II. Module 2
- 1. Zabbix Configuration
- 2. Getting Around in Zabbix
- 3. Groups, Users, and Permissions
- 4. Monitoring with Zabbix
- Introduction
- Active agents
- Passive agents
- Extending agents
- SNMP checks
- Internal checks
- Zabbix trapper
- IPMI checks
- JMX checks
- Aggregate checks
- External checks
- Database monitoring
- Checks with SSH
- Checks with Telnet
- Calculated checks
- Building web scenarios
- Monitoring web scenarios
- Some advanced monitoring tricks
- Autoinventory
- 5. Testing with Triggers in Zabbix
- 6. Working with Templates
- 7. Data Visualization and Reporting in Zabbix
- 8. Monitoring VMware and Proxies
- 9. Autodiscovery
- 10. Zabbix Maintenance and API
- C. Upgrading and Troubleshooting Zabbix
- III. Module 3
- 1. Deploying Zabbix
- 2. Distributed Monitoring
- 3. High Availability and Failover
- Understanding high availability
- Understanding the levels of IT service
- Some considerations about high availability
- Implementing high availability on a web server
- Configuring the Zabbix server for high availability
- Implementing high availability for a database
- Summary
- 4. Collecting Data
- 5. Visualizing Data
- 6. Managing Alerts
- 7. Managing Templates
- 8. Handling External Scripts
- 9. Extending Zabbix
- 10. Integrating Zabbix
- D. Bibliography
- Index
Sometimes triggers in Zabbix are too sensitive and you get notifications all the time because of quick repeated status changes; this is what we call flapping. This could be for example a swap file that is growing and shrinking all the time, making Zabbix send notifications that there is not enough free space left and a few seconds later going back in an OK state because there is enough space again to come back in alarm once again, a few seconds later. Another example of flapping could be the CPU load going over and under the threshold every x number of seconds. Let's see how we can solve this.
For this recipe, we only need a Zabbix server with an agent installed on the Zabbix server or some host and of course access with a super administrator account, like the one that comes standard with the installation.
- Let's monitor the free space left for our our MySQL database. Create an item that checks the value of the free space of a MySQL volume in percent or if you prefer another volume on your hard drive.
- If you don't know how to create items, have a look at Chapter 4, Monitoring Zabbix.
- Next go to Configuration | Hosts | Triggers and press the Create a trigger button for this item.
- Add this code in the expression box and adjust the volume for MySQLto your needs:
({TRIGGER.VALUE}=0 & {MySQL:vfs.fs.size[/var/lib/mysql,pfree].last(0)}<10) | ({TRIGGER.VALUE}=1 & {MySQL:vfs.fs.size[/var/lib/mysql,pfree].last(0)}<30) - Fill in the Name of your trigger and select a Severity.
- Save your trigger and try to add some extra data to your volume to see if it works.
We made use of a new macro, {trigger.value}. We know that once a trigger is in the problem state, it is 1 and once a trigger is in the OK state it is 0. By making use of the operator OR operator (|) we can tell our trigger to change to a problem state if our volume is less than 10 GB, or to remain into a problem state if the state was already in error and the volume has still less than 30 GB free space left.
Our trigger will come back in the OK state once the free space in our volume is more than 30 GB. This is possible because the macro {TRIGGER.VALUE} always returns the current trigger value. The first line defines when the problem starts. In our case, when there is less than 10 percent free space for the MySQL volume.
The second line defines the condition that keeps our trigger in problem state. In our case, this will be less than 30 percent free space.
There are more ways to do smart monitoring, for example, we can make use of the fuzzytime() function to see if there is still contact with our proxy. Example: {Zabbix server:zabbix[proxy,<proxy name>,last access].fuzzytime(300)}=0. This will alarm us if there is no contact for 300 seconds.
We can also do a time shift in Zabbix. This means that we can compare a value from an item with the value from example:
yesterday. server:system.cpu.load.avg(1h)}/{server:system.cpu.load.avg(1h,1d) }>2This expression for example will check the load for 1h today and verify it with our server with the load from yesterday and give a warning if the load is more than 2 times.
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