Fix a bug where the scheduler may panic when preemption is enabled. The conditions are a bit complicated:
A job with higher priority that schedule multiple allocations that preempt other multiple allocations on the same node, due to port/network/device assignments.
The cause of the bug is incidental mutation of internal cached data. `RankedNode` computes and cache proposed allocations in https://github.com/hashicorp/nomad/blob/v1.1.6/scheduler/rank.go#L42-L53 . But scheduler then mutates the list to remove pre-emptable allocs in https://github.com/hashicorp/nomad/blob/v1.1.6/scheduler/rank.go#L293-L294, and `RemoveAllocs` mutates and sets the tail of cached slice with `nil`s triggering a nil-pointer derefencing case.
I fixed the issue by avoiding the mutation in `RemoveAllocs` - the micro-optimization there doesn't seem necessary.
Fixes https://github.com/hashicorp/nomad/issues/11342
Meant for development purposes only, so one can compile binary on a
macos host then start a Docker container or scp the binary to a linux
host easily.
The resulting binary is statically linked and has very subtle
differences. e.g. static binaries use go native network stack that
honor /etc/hosts and /etc/resolve differently from the glibc
implementation. In development environment, I don't expect these to
materially change our experience.
Fix a test corruption issue, where a test accidentally unsets
the `NOMAD_LICENSE` environment variable, that's relied on by some
tests.
As a habit, tests should always restore the environment variable value
on test completion. Golang 1.17 introduced
[`t.Setenv`](https://pkg.go.dev/testing#T.Setenv) to address this issue.
However, as 1.0.x and 1.1.x branches target golang 1.15 and 1.16, I
opted to use a helper function to ease backports.
* Include region and namespace in CLI output
* Add region and prefix matching for server members
* Add namespace and region API outputs to cluster metadata folder
* Add region awareness to WaitForClient helper function
* Add helper functions for SliceStringHasPrefix and StringHasPrefixInSlice
* Refactor test client agent generation
* Add tests for region
* Add changelog
We see this error all the time
```
no handler registered for event
event.Message=, event.Annotations=, event.Timestamp=0001-01-01T00:00:00Z, event.TaskName=, event.AllocID=, event.TaskID=,
```
So we're handling an even with all default fields. I noted that this can
happen if only err is set as in
```
func (d *driverPluginClient) handleTaskEvents(reqCtx context.Context, ch chan *TaskEvent, stream proto.Driver_TaskEventsClient) {
defer close(ch)
for {
ev, err := stream.Recv()
if err != nil {
if err != io.EOF {
ch <- &TaskEvent{
Err: grpcutils.HandleReqCtxGrpcErr(err, reqCtx, d.doneCtx),
}
}
```
In this case Err fails to be serialized by the logger, see this test
```
ev := &drivers.TaskEvent{
Err: fmt.Errorf("errz"),
}
i.logger.Warn("ben test", "event", ev)
i.logger.Warn("ben test2", "event err str", ev.Err.Error())
i.logger.Warn("ben test3", "event err", ev.Err)
ev.Err = nil
i.logger.Warn("ben test4", "nil error", ev.Err)
2021-10-06T22:37:56.736Z INFO nomad.stdout {"@level":"warn","@message":"ben test","@module":"client.driver_mgr","@timestamp":"2021-10-06T22:37:56.643900Z","driver":"mock_driver","event":{"TaskID":"","TaskName":"","AllocID":"","Timestamp":"0001-01-01T00:00:00Z","Message":"","Annotations":null,"Err":{}}}
2021-10-06T22:37:56.736Z INFO nomad.stdout {"@level":"warn","@message":"ben test2","@module":"client.driver_mgr","@timestamp":"2021-10-06T22:37:56.644226Z","driver":"mock_driver","event err str":"errz"}
2021-10-06T22:37:56.736Z INFO nomad.stdout {"@level":"warn","@message":"ben test3","@module":"client.driver_mgr","@timestamp":"2021-10-06T22:37:56.644240Z","driver":"mock_driver","event err":"errz"}
2021-10-06T22:37:56.736Z INFO nomad.stdout {"@level":"warn","@message":"ben test4","@module":"client.driver_mgr","@timestamp":"2021-10-06T22:37:56.644252Z","driver":"mock_driver","nil error":null}
```
Note in the first example err is set to an empty object and the error is
lost.
What we want is the last two examples which call out the err field
explicitly so we can see what it is in this case
FailoverHeartbeatTTL is the amount of time to wait after a server leader failure
before considering reallocating client tasks. This TTL should be fairly long as
the new server leader needs to rebuild the entire heartbeat map for the
cluster. In deployments with a small number of machines, the default TTL (5m)
may be unnecessary long. Let's allow operators to configure this value in their
config files.
