Chapter 8. Responsive restarts and security certificates

MicroShift depends on device IP addresses and system-wide clock settings to remain consistent during its runtime. However, these settings might occasionally change on edge devices.

For example, DHCP or Network Time Protocol (NTP) updates can change times. When these changes occur, some MicroShift components might stop functioning properly. To mitigate this situation, MicroShift monitors the IP address and system time and restarts if either setting changes.

The threshold for a clock-driven restart is a time change of greater than 10 seconds in either direction. Small drifts during regular NTP service adjustments do not trigger a restart.

MicroShift certificates are digital certificates that secure communication with communication protocols such as HTTPS. They fall into two basic categories:

MicroShift restarts automatically depending on certificate age.

Certificates that are expired or close to their expiration dates must be rotated to ensure continued MicroShift operation. Certificate rotation can occur automatically.

When MicroShift restarts for any reason, certificates that are close to expiring are rotated. A certificate that expires soon, or has already expired, can also cause an automatic MicroShift restart to perform a rotation.