qemu/docs/COLO-FT.txt

18 Both primary VM (PVM) and secondary VM (SVM) run in parallel. They receive the
27 The primary node running the PVM, and the secondary node running the SVM
33 primary node, and then forwarded to the secondary node, so that both the PVM
44   Primary Node                                                            Secondary Node
47 | Primary VM |  +-----------+-----------+       +-----------+------------+  |Secondary VM|
88 Runs on both the primary and secondary nodes, to periodically check platform
90 the heartbeat stops responding, the secondary node will trigger a failover
95 and sends it to secondary VM's which makes sure the context of secondary VM's
101 to make sure the state of VM in Secondary side is always consistent with VM in
105 Delivers packets to Primary and Secondary, and then compare the responses from
150 127.0.0.1 is the Primary Host and 127.0.0.2 is the Secondary Host.
180 2. Secondary:
185 # imagefolder="/mnt/vms/colo-test-secondary"
188 # qemu-img create -f qcow2 $imagefolder/secondary-active.qcow2 10G
190 # qemu-img create -f qcow2 $imagefolder/secondary-hidden.qcow2 10G
193    -device piix3-usb-uhci -device usb-tablet -name secondary \
202    -drive if=none,id=childs0,driver=replication,mode=secondary,file.driver=qcow2,\
203 top-id=colo-disk0,file.file.filename=$imagefolder/secondary-active.qcow2,\
204 file.backing.driver=qcow2,file.backing.file.filename=$imagefolder/secondary-hidden.qcow2,\
211 3. On Secondary VM's QEMU monitor, issue command
235      secondary qemu.
244 If you killed the Secondary, then follow "Primary Failover". After that,
247 If you killed the Primary, then follow "Secondary Failover". After that,
248 if you want to resume the replication, follow "Secondary resume replication"
251 The Secondary died, resume on the Primary
262 == Secondary Failover ==
263 The Primary died, resume on the Secondary and prepare to become the new Primary
281 Resume replication after new Secondary is up.
283 Start the new Secondary (Steps 2 and 3 above), then on the Primary:
303 If this Primary previously was a Secondary, then we need to insert the
307 == Secondary resume replication ==
308 Become Primary and resume replication after new Secondary is up. Note
309 that now 127.0.0.1 is the Secondary and 127.0.0.2 is the Primary.
311 Start the new Secondary (Steps 2 and 3 above, but with primary_ip=127.0.0.2),
312 then on the old Secondary: