[release-4.12] WIP: DNM: kubelet: devices: skip allocation for running pods #1636
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When kubelet initializes, runs admission for pods and possibly allocated requested resources. We need to distinguish between node reboot (no containers running) versus kubelet restart (containers potentially running). Running pods should always survive kubelet restart. This means that device allocation on admission should not be attempted, because if a container requires devices and is still running when kubelet is restarting, that container already has devices allocated and working. Thus, we need to properly detect this scenario in the allocation step and handle it explicitely. We need to inform the devicemanager about which pods are already running. Note that if container runtime is down when kubelet restarts, the approach implemented here won't work. In this scenario, so on kubelet restart containers will again fail admission, hitting kubernetes#118559 again. This scenario should however be pretty rare. Signed-off-by: Francesco Romani <fromani@redhat.com>
One of the contributing factors of issues kubernetes#118559 and kubernetes#109595 hard to debug and fix is that the devicemanager has very few logs in important flow, so it's unnecessarily hard to reconstruct the state from logs. We add minimal logs to be able to improve troubleshooting. We add minimal logs to be backport-friendly, deferring a more comprehensive review of logging to later PRs. Signed-off-by: Francesco Romani <fromani@redhat.com>
Signed-off-by: Francesco Romani <fromani@redhat.com>
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WIP: DNM: to run CI