Add a new driver capability: RemoteTasks.
When a task is run by a driver with RemoteTasks set, its TaskHandle will
be propagated to the server in its allocation's TaskState. If the task
is replaced due to a down node or draining, its TaskHandle will be
propagated to its replacement allocation.
This allows tasks to be scheduled in remote systems whose lifecycles are
disconnected from the Nomad node's lifecycle.
See https://github.com/hashicorp/nomad-driver-ecs for an example ECS
remote task driver.
The change was intended to fix a case where a canary alloc may fail to
be rescheduled if all the other allocs fail as well (e.g. if all allocs
happen to be placed on a node that died). However, it introduced some
unintended side-effects.
Reverting the change for now and will investigate further.
This change fixes a bug where lost/failed allocations are replaced by
allocations with the latest versions, even if the version hasn't been
promoted yet.
Now, when generating a plan for lost/failed allocations, the scheduler
first checks if the current deployment is in Canary stage, and if so, it
ensures that any lost/failed allocations is replaced one with the latest
promoted version instead.
The reconcile loop sets `DeploymentState.DesiredCanaries` only on the first
pass through the loop and if the job is not paused/pending. In MRD,
deployments will make one pass though the loop while "pending", and were not
ever getting `DesiredCanaries` set. We can't set it in the initial
`DeploymentState` constructor because the first pass through setting up
canaries expects it's not there yet. However, this value is static for a given
version of a job because it's coming from the update stanza, so it's safe to
re-assign the value on subsequent passes.
The field name `Deployment.TaskGroups` contains a map of `DeploymentState`,
which makes it a little harder to follow state updates when combined with
inconsistent naming conventions, particularly when we also have the state
store or actual `TaskGroup`s in scope. This changeset changes all uses to
`dstate` so as not to be confused with actual TaskGroups.
If a job update includes a task group that has no changes, those allocations
have their version bumped in-place. The ends up triggering an eval from
`deploymentwatcher` when it verifies their health. Although this eval is a
no-op, we were only treating pending deployments the same as paused when
the deployment was a new MRD. This means that any eval after the initial one
will kick off the deployment, and that caused pending deployments to "jump
the queue" and run ahead of schedule, breaking MRD invariants and resulting in
a state with all regions blocked.
This behavior can be replicated even in the case of job updates with no
in-place updates by patching `deploymentwatcher` to inject a spurious no-op
eval. This changeset fixes the behavior by treating pending deployments the
same as paused in all cases in the reconciler.
Deployments should wait until kicked off by `Job.Register` so that we can
assert that all regions have a scheduled deployment before starting any
region. This changeset includes the OSS fixes to support the ENT work.
`IsMultiregionStarter` has no more callers in OSS, so remove it here.
Pre-0.12.0 beta, a deployment was considered "complete" if it was
successful. But with MRD we have "blocked" and "unblocking" states as well. We
did not consider the case where a concurrent alloc health status update
triggers a `Compute` call on a deployment that's moved from "blocked" to
"unblocking" (it's a small window), which caused an extra pass thru the
`nextRegion` logic in `deploymentwatcher` and triggered an error when later
transitioning to "successful".
This changeset makes sure we don't overwrite that status.
In #8209 we fixed the `max_parallel` stanza for multiregion by introducing the
`IsMultiregionStarter` check, but didn't apply it to the earlier place its
required. The result is that deployments start but don't place allocations.
If `max_parallel` is not set, all regions should begin in a `running` state
rather than a `pending` state. Otherwise the first region is set to `running`
and then all the remaining regions once it enters `blocked. That behavior is
technically correct in that we have at most `max_parallel` regions running,
but definitely not what a user expects.
The `paused` state is used as an operator safety mechanism, so that they can
debug a deployment or halt one that's causing a wider failure. By using the
`paused` state as the first state of a multiregion deployment, we risked
resuming an intentionally operator-paused deployment because of activity in a
peer region.
This changeset replaces the use of the `paused` state with a `pending` state,
and provides a `Deployment.Run` internal RPC to replace the use of the
`Deployment.Pause` (resume) RPC we were using in `deploymentwatcher`.
* `nextRegion` should take status parameter
* thread Deployment/Job RPCs thru `nextRegion`
* add `nextRegion` calls to `deploymentwatcher`
* use a better description for paused for peer
* scheduler/reconcile: set FollowupEvalID on lost stop_after_client_disconnect
* scheduler/reconcile: thread follupEvalIDs through to results.stop
* scheduler/reconcile: comment typo
* nomad/_test: correct arguments for plan.AppendStoppedAlloc
* scheduler/reconcile: avoid nil, cleanup handleDelayed(Lost|Reschedules)
* client/heartbeatstop: reversed time condition for startup grace
* scheduler/generic_sched: use `delayInstead` to avoid a loop
Without protecting the loop that creates followUpEvals, a delayed eval
is allowed to create an immediate subsequent delayed eval. For both
`stop_after_client_disconnect` and the `reschedule` block, a delayed
eval should always produce some immediate result (running or blocked)
and then only after the outcome of that eval produce a second delayed
eval.
* scheduler/reconcile: lostLater are different than delayedReschedules
Just slightly. `lostLater` allocs should be used to create batched
evaluations, but `handleDelayedReschedules` assumes that the
allocations are in the untainted set. When it creates the in-place
updates to those allocations at the end, it causes the allocation to
be treated as running over in the planner, which causes the initial
`stop_after_client_disconnect` evaluation to be retried by the worker.
* jobspec, api: add stop_after_client_disconnect
* nomad/state/state_store: error message typo
* structs: alloc methods to support stop_after_client_disconnect
1. a global AllocStates to track status changes with timestamps. We
need this to track the time at which the alloc became lost
originally.
2. ShouldClientStop() and WaitClientStop() to actually do the math
* scheduler/reconcile_util: delayByStopAfterClientDisconnect
* scheduler/reconcile: use delayByStopAfterClientDisconnect
* scheduler/util: updateNonTerminalAllocsToLost comments
This was setup to only update allocs to lost if the DesiredStatus had
already been set by the scheduler. It seems like the intention was to
update the status from any non-terminal state, and not all lost allocs
have been marked stop or evict by now
* scheduler/testing: AssertEvalStatus just use require
* scheduler/generic_sched: don't create a blocked eval if delayed
* scheduler/generic_sched_test: several scheduling cases
When an alloc is due to be rescheduleLater, it goes through the
reconciler twice: once to be ignored with a follow up evals, and once
again when processing the follow up eval where they appear as
rescheduleNow.
Here, we ignore them in the first run and mark them as stopped in second
iteration; rather than stop them twice.
Currently, when an alloc fails and is rescheduled, the alloc desired
state remains as "run" and the nomad client may not free the resources.
Here, we ensure that an alloc is marked as stopped when it's
rescheduled.
Notice the Desired Status and Description before and after this change:
Before:
```
mars-2:nomad notnoop$ nomad alloc status 02aba49e
ID = 02aba49e
Eval ID = bb9ed1d2
Name = example-reschedule.nodes[0]
Node ID = 5853d547
Node Name = mars-2.local
Job ID = example-reschedule
Job Version = 0
Client Status = failed
Client Description = Failed tasks
Desired Status = run
Desired Description = <none>
Created = 10s ago
Modified = 5s ago
Replacement Alloc ID = d6bf872b
Task "payload" is "dead"
Task Resources
CPU Memory Disk Addresses
0/100 MHz 24 MiB/300 MiB 300 MiB
Task Events:
Started At = 2019-06-06T21:12:45Z
Finished At = 2019-06-06T21:12:50Z
Total Restarts = 0
Last Restart = N/A
Recent Events:
Time Type Description
2019-06-06T17:12:50-04:00 Not Restarting Policy allows no restarts
2019-06-06T17:12:50-04:00 Terminated Exit Code: 1
2019-06-06T17:12:45-04:00 Started Task started by client
2019-06-06T17:12:45-04:00 Task Setup Building Task Directory
2019-06-06T17:12:45-04:00 Received Task received by client
```
After:
```
ID = 5001ccd1
Eval ID = 53507a02
Name = example-reschedule.nodes[0]
Node ID = a3b04364
Node Name = mars-2.local
Job ID = example-reschedule
Job Version = 0
Client Status = failed
Client Description = Failed tasks
Desired Status = stop
Desired Description = alloc was rescheduled because it failed
Created = 13s ago
Modified = 3s ago
Replacement Alloc ID = 7ba7ac20
Task "payload" is "dead"
Task Resources
CPU Memory Disk Addresses
21/100 MHz 24 MiB/300 MiB 300 MiB
Task Events:
Started At = 2019-06-06T21:22:50Z
Finished At = 2019-06-06T21:22:55Z
Total Restarts = 0
Last Restart = N/A
Recent Events:
Time Type Description
2019-06-06T17:22:55-04:00 Not Restarting Policy allows no restarts
2019-06-06T17:22:55-04:00 Terminated Exit Code: 1
2019-06-06T17:22:50-04:00 Started Task started by client
2019-06-06T17:22:50-04:00 Task Setup Building Task Directory
2019-06-06T17:22:50-04:00 Received Task received by client
```
This PR changes behavior of the scheduler such that a task group with a
deployment that is failed or paused will not cause the scheduler to skip
migrations.
The reason for this change is that it causes a bad UX when draining
nodes with allocations that are part of a failed/paused deployment.
These operations should not be coupled in any way and this remedies
that.
Prior behavior was still correct, but required either jobs to
transistion to a healthy state or for the node to hit its drain
deadline.
Michael Schurter