29 Upgrade notes for 4.0.20

Item changes

The Timeout configuration parameter is now used for web.page.get, web.page.regexp and web.page.perf items.

Maintenance and Daylight Saving Time

In previous Zabbix versions, maintenance period calculation was unaware of the possible effects caused by Daylight Saving Time change resulting in unpredictable behaviours. In the new version Daylight Saving Time (DST) change is cared for and should not unpredictably affect how long the maintenance will be. Let's say we have a two-hour maintenance that usually starts at 1am and finishes at 3am. If after one hour of maintenance (at 2am) a DST change happens and current time changes from 2:00 to 3:00, the maintenance will continue for one more hour till 4:00.

Docker appliance support dropped

Zabbix Docker Appliance image has been decommissioned and will not be available for 4.0.20 and newer releases. Please use a separate Docker image for each component instead of the all-in-one solution.

Non-root permissions implemented for Docker images

Zabbix Docker images have been updated to implement non-root container best practices. Due to the change:

• All directories have been restricted for the container user, except directories which are required for the container. For example, /etc/zabbix/ with Zabbix component configuration files.
• Ports 80 and 443 have been changed to 8080 and 8443, because usage of all ports <1024 is restricted for non-privileged users. Zabbix web interface images have been updated to use non-privileged ports 8080, 8443; Zabbix snmptrap images port 1162.
• All Zabbix images are updated to use a non-privileged user. By default, 'zabbix' with UID 1997.

A known issue: Nginx based images do not run under root. Will be fixed soon.