With our first proxy configured, let's discuss its operation and the benefits it provides in more detail. Let's start with the main benefits:
- A proxy collects data when the server is not available
- A proxy reduces the number of connections to and from remote environments
- A proxy allows us to use incoming connections for polled items
We talked about the proxy retrieving configuration data from the server, and we talked about it having a local database. The Zabbix proxy always needs a local database, and this database holds information on the hosts the proxy is supposed to monitor. The same database also holds all the data the proxy has collected, and if the server cannot be reached, that data is not lost. For how long? By default, data is kept for one hour. This can be configured in the zabbix_proxy.conf file, in the ProxyOfflineBuffer parameter. It can be set up to 30 days, but beware of running out of disk space, as well as of the potential to overload the Zabbix server when connectivity is backâwe will discuss that risk in more detail later:
Fewer connections to remote environments can be very important, too. Monitoring using passive items means one connection for each value. With active items, it's a bit better; multiple values will often be sent in a single connection. But the proxy pools up to 1,000 values in a single connection. That is done even when they are of different types, such as agent, SNMP, IPMI, and SSH items. Fewer connections means healthier firewalls and other network devices, and much better performance from smaller total latency and less work for the Zabbix server to handle the incoming connections from Zabbix agents:
The third main benefit is the ability to receive incoming connections on the server side and still gather data by polling devices. For example, when monitoring a customer environment, the Zabbix server might have no access to the network devices. The Zabbix proxy could connect to them, collect data using SNMP, and then connect to the server to send the data. Also, keep in mind that only a single port for a single address would have to be opened in firewalls, as opposed to a lot of ports for all of the monitored devices when a proxy is not used:
There are a few more benefits that Zabbix proxies provide:
- Single point of control for all proxies on the Zabbix server
- Ability to use multiple Java gateways
As proxies grab the configuration data from the Zabbix server, the configuration of all proxies is done on a single system. This also allows us to ship out small, preconfigured devices that are plugged into a remote environment. As long as they get network connectivity and can connect to the Zabbix server, all configuration regarding what should be monitored can be changed at will from the Zabbix server.
As for Java gateways, we discussed them in Chapter 15, Monitoring Java Applications. Only a single Java gateway could be configured for the Zabbix server, but a gateway may also be configured for each proxy. With proxies being simple to set up, it's fairly easy to have lots of Java gateways working on behalf of a single Zabbix server. Additionally, the Java gateway only supports connections from the server to the gateway. Using an active proxy in front of the gateway allows Java Management Extensions (JMX) monitoring using incoming connections to the Zabbix server:
