DLPX-79034 systemd-networkd releases its DHCP lease on restart #358
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sebroy
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naveen-singh-delphix,
prakashsurya,
sdimitro and
willguyette
naveen-singh-delphix
approved these changes
Feb 3, 2022
sebroy
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Feb 4, 2022
delphix#358)" This reverts commit cfe52e4.
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This PR addresses an issue that was introduced with the new version of systemd-networkd in Ubuntu 20.04, which is that when systemd-networkd stops (which happens when it restarts as part of applying an updated network configuration, for example), it releases its DHCP lease. A new lease is acquired when systemd-networkd starts again, but this leaves a window where the system has no IP address nor routes (those that were tied to the DHCP lease).
The fix is to configure systemd-networkd not to drop the lease on stop. A lease can be explicitly dropped by deleting a DHCP address (the only time when a lease should be dropped...).
This bug was responsible for the multitudes of dx-test failures documented in https://delphix.atlassian.net/browse/TOOL-12800, and there's a comment in that bug describing the RCA that lead to this bug fix.
ab-pre-push: http://selfservice.jenkins.delphix.com/job/appliance-build-orchestrator-pre-push/695/