The simulator tracks only active processes. Rebooted or killed processes
are removed from the list of processes, and only get added back when the
process is rebooted and starts up again. This causes a problem for the
`RebootProcessAndSwitch` kill type, which wants to simultaneously reboot
all machines in a cluster and change their cluster file. If a machine is
currently being rebooted, it will miss the reboot process and switch
command.
The fix is to add a check when a process is being started in simulation.
If the process has had its cluster file changed and the cluster is in a
state where all processes should have had their cluster files reverted
to the original value, the simulator will now send a
`RebootProcessAndSwitch` signal right when the process is started. This
will cause an extra reboot, but should correctly switch the process back
to its original, correct cluster file, allowing the cluster to fully
recover all clusters.
Note that the above issue should only affect simulation, due to how the
simulator tracks processes and handles kill signals.
This commit also adds a field to each process struct to determine
whether the process is being run in a DR cluster in the simulation run.
This is needed because simulation does not differentiate between
processes in different clusters (other than by the IP), and some
processes needed to switch clusters and some simply needed to be
rebooted.
The simulator tracks only active processes. Rebooted or killed processes
are removed from the list of processes, and only get added back when the
process is rebooted and starts up again. This causes a problem for the
`RebootProcessAndSwitch` kill type, which wants to simultaneously reboot
all machines in a cluster and change their cluster file. If a machine is
currently being rebooted, it will miss the reboot process and switch
command.
The fix is to add a check when a process is being started in simulation.
If the process has had its cluster file changed and the cluster is in a
state where all processes should have had their cluster files reverted
to the original value, the simulator will now send a
`RebootProcessAndSwitch` signal right when the process is started. This
will cause an extra reboot, but should correctly switch the process back
to its original, correct cluster file, allowing the cluster to fully
recover all clusters.
Note that the above issue should only affect simulation, due to how the
simulator tracks processes and handles kill signals.
This commit also adds a field to each process struct to determine
whether the process is being run in a DR cluster in the simulation run.
This is needed because simulation does not differentiate between
processes in different clusters (other than by the IP), and some
processes needed to switch clusters and some simply needed to be
rebooted.
* proof of concept
* use code-probe instead of test
* code probe working on gcc
* code probe implemented
* renamed TestProbe to CodeProbe
* fixed refactoring typo
* support filtered output
* print probes at end of simulation
* fix missed probes print
* fix deduplication
* Fix refactoring issues
* revert bad refactor
* make sure file paths are relative
* fix more wrong refactor changes
* Add simulation test for 1 data hall + 1 machine failure case.
* Disable BUGGIFY for DEGRADED_RESET_INTERVAL.
A simulation test discovered a situation where machines attempting to connect
to a dead coordinator (with a well-known endpoint) were getting themselves
marked degraded. This flapping of the degraded state prevented recovery from
completing, as it started over any time it noticed that tlogs on degraded
hosts could be relocated to non-degraded ones.
bin/fdbserver -r simulation -f tests/rare/CycleWithDeadHall.toml -b on -s 276841956
Markus Pilman