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apache / cloudstack

Apache CloudStack is an opensource Infrastructure as a Service (IaaS) cloud computing platform
https://cloudstack.apache.org/
Apache License 2.0
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KVM: Change SystemVM patching to Qemu Fw Cfg #4112

Closed rohityadavcloud closed 2 years ago

rohityadavcloud commented 4 years ago

The systemvms are patching on KVM are currently performed patch.sh that uses qemu-agent-command (a serial-device mechanism) and consumed in the systemvms via qemu-guest-agent. Newer qemu versions (at least 2.2+) can make use of the qemu fw cfg device to pass key/value strings for the cmdline without using a more brittle/low-level approach much like XenServer and VMware, and inside the systemvm they can consume the value for the cmdline at /sys/firmware/qemu_fw_cfg/by_name/... path which is available in newer kernels.

Refs: https://github.com/qemu/qemu/blob/master/docs/specs/fw_cfg.txt https://github.com/torvalds/linux/blob/master/drivers/firmware/qemu_fw_cfg.c

ISSUE TYPE
COMPONENT NAME
VR, SSVM, CPVM
DaanHoogland commented 3 years ago

@rhtyd are you talking of just the install time patching or live updates of the systemvm here? and do you think we need to implement this before the next systemvm update?