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
Add a new hostname string parameter to the network block which
allows operators to specify the hostname of the network namespace.
Changing this causes a destructive update to the allocation and it
is omitted if empty from API responses. This parameter also supports
interpolation.
In order to have a hostname passed as a configuration param when
creating an allocation network, the CreateNetwork func of the
DriverNetworkManager interface needs to be updated. In order to
minimize the disruption of future changes, rather than add another
string func arg, the function now accepts a request struct along with
the allocID param. The struct has the hostname as a field.
The in-tree implementations of DriverNetworkManager.CreateNetwork
have been modified to account for the function signature change.
In updating for the change, the enhancement of adding hostnames to
network namespaces has also been added to the Docker driver, whilst
the default Linux manager does not current implement it.
When a system or sysbatch job specify constraints that none of the
current nodes meet, report a warning to the user.
Also, for sysbatch job, mark the job as dead as a result.
A sample run would look like:
```
$ nomad job run ./example.nomad
==> 2021-08-31T16:57:35-04:00: Monitoring evaluation "b48e8882"
2021-08-31T16:57:35-04:00: Evaluation triggered by job "example"
==> 2021-08-31T16:57:36-04:00: Monitoring evaluation "b48e8882"
2021-08-31T16:57:36-04:00: Evaluation status changed: "pending" -> "complete"
==> 2021-08-31T16:57:36-04:00: Evaluation "b48e8882" finished with status "complete" but failed to place all allocations:
2021-08-31T16:57:36-04:00: Task Group "cache" (failed to place 1 allocation):
* Constraint "${meta.tag} = bar": 2 nodes excluded by filter
* Constraint "${attr.kernel.name} = linux": 1 nodes excluded by filter
$ nomad job status example
ID = example
Name = example
Submit Date = 2021-08-31T16:57:35-04:00
Type = sysbatch
Priority = 50
Datacenters = dc1
Namespace = default
Status = dead
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
cache 0 0 0 0 0 0
Allocations
No allocations placed
```
When a node becomes ready, create an eval for all system jobs across
namespaces.
The previous code uses `job.ID` to deduplicate evals, but that ignores
the job namespace. Thus if there are multiple jobs in different
namespaces sharing the same ID/Name, only one will be considered for
running in the new node. Thus, Nomad may skip running some system jobs
in that node.
This PR implements a new "System Batch" scheduler type. Jobs can
make use of this new scheduler by setting their type to 'sysbatch'.
Like the name implies, sysbatch can be thought of as a hybrid between
system and batch jobs - it is for running short lived jobs intended to
run on every compatible node in the cluster.
As with batch jobs, sysbatch jobs can also be periodic and/or parameterized
dispatch jobs. A sysbatch job is considered complete when it has been run
on all compatible nodes until reaching a terminal state (success or failed
on retries).
Feasibility and preemption are governed the same as with system jobs. In
this PR, the update stanza is not yet supported. The update stanza is sill
limited in functionality for the underlying system scheduler, and is
not useful yet for sysbatch jobs. Further work in #4740 will improve
support for the update stanza and deployments.
Closes#2527
Updates to the datacenter field should be destructive for any allocation that
is on a node no longer in the list of datacenters, but inplace for any
allocation on a node that is still in the list. Add a check for this change to
the system and generic schedulers after we've checked the task definition for
updates and obtained the node for each current allocation.
The `QuotaIterator` is used as the source of nodes passed into feasibility
checking for constraints. Every node that passes the quota check counts the
allocation resources agains the quota, and as a result we count nodes which
will be later filtered out by constraints. Therefore for jobs with
constraints, nodes that are feasibility checked but fail have been counted
against quotas. This failure mode is order dependent; if all the unfiltered
nodes happen to be quota checked first, everything works as expected.
This changeset moves the `QuotaIterator` to happen last among all feasibility
checkers (but before ranking). The `QuotaIterator` will never receive filtered
nodes so it will calculate quotas correctly.
Glint pulled in an updated version of mitchellh/go-testing-interface
which broke some existing tests because the update added a Parallel()
method to testing.T. This switches to the standard library testing.TB
which doesn't have a Parallel() method.
The reconciler has some complicated behavior when there are already running
allocations from a previous version of the job that we want to keep, as
happens during a rollback. Document this behavior with a test.
Cluster operators want to have better control over memory
oversubscription and may want to enable/disable it based on their
experience.
This PR adds a scheduler configuration field to control memory
oversubscription. It's additional field that can be set in the [API via Scheduler Config](https://www.nomadproject.io/api-docs/operator/scheduler), or [the agent server config](https://www.nomadproject.io/docs/configuration/server#configuring-scheduler-config).
I opted to have the memory oversubscription be an opt-in, but happy to change it. To enable it, operators should call the API with:
```json
{
"MemoryOversubscriptionEnabled": true
}
```
If memory oversubscription is disabled, submitting jobs specifying `memory_max` will get a "Memory oversubscription is not
enabled" warnings, but the jobs will be accepted without them accessing
the additional memory.
The warning message is like:
```
$ nomad job run /tmp/j
Job Warnings:
1 warning(s):
* Memory oversubscription is not enabled; Task cache.redis memory_max value will be ignored
==> Monitoring evaluation "7c444157"
Evaluation triggered by job "example"
==> Monitoring evaluation "7c444157"
Evaluation within deployment: "9d826f13"
Allocation "aa5c3cad" created: node "9272088e", group "cache"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "7c444157" finished with status "complete"
# then you can examine the Alloc AllocatedResources to validate whether the task is allowed to exceed memory:
$ nomad alloc status -json aa5c3cad | jq '.AllocatedResources.Tasks["redis"].Memory'
{
"MemoryMB": 256,
"MemoryMaxMB": 0
}
```
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.
This PR adds the common OSS changes for adding support for Consul Namespaces,
which is going to be a Nomad Enterprise feature. There is no new functionality
provided by this changeset and hopefully no new bugs.
Start tracking a new MemoryMaxMB field that represents the maximum memory a task
may use in the client. This allows tasks to specify a memory reservation (to be
used by scheduler when placing the task) but use excess memory used on the
client if the client has any.
This commit adds the server tracking for the value, and ensures that allocations
AllocatedResource fields include the value.
node drain: use msgtype on txn so that events are emitted
wip: encoding extension to add Node.Drain field back to API responses
new approach for hiding Node.SecretID in the API, using `json` tag
documented this approach in the contributing guide
refactored the JSON handlers with extensions
modified event stream encoding to use the go-msgpack encoders with the extensions
Add a `PerAlloc` field to volume requests that directs the scheduler to test
feasibility for volumes with a source ID that includes the allocation index
suffix (ex. `[0]`), rather than the exact source ID.
Read the `PerAlloc` field when making the volume claim at the client to
determine if the allocation index suffix (ex. `[0]`) should be added to the
volume source ID.
Callers of `CSIVolumeByID` are generally assuming they should receive a single
volume. This potentially results in feasibility checking being performed
against the wrong volume if a volume's ID is a prefix substring of other
volume (for example: "test" and "testing").
Removing the incorrect prefix matching from `CSIVolumeByID` breaks prefix
matching in the command line client. Add the required elements for prefix
matching to the commands and API.
When multiple CSI volumes are requested, the feasibility check could return
early for read/write volumes with free claims, even if a later volume in the
request was not feasible for any other reason (including not existing at
all). This can result in random failure to fail feasibility checking,
depending on how the map of volumes was being ordered at runtime.
Remove the early return from the feasibility check. Add a test to verify that
missing volumes in the map will cause a failure; this test will not catch a
regression every test run because of the random map ordering, but any failure
will be caught over the course of several CI runs.
This PR fixes a bug where tasks with Connect services could be
triggered to destructively update (i.e. placed in a new alloc)
when no update should be necessary.
Fixes#10077
* Persist shared allocated ports for inplace update
Ports were not copied over when performing inplace updates in the
generic scheduler
* changelog
* drop spew
AllocatedSharedResources were not being copied over to the new
allocation struct the scheduler makes during inplace updates. This
caused downstream issues after the plan was applied, namely the shared
ports were dropped causing issues with service
registration/deregistration.
test that shared ports are preserved
change log, also carry over shared network
copy networks
This PR enables users of Nomad < 0.12 to upgrade to Nomad 0.12
and beyond. Nomad 0.12 introduced a network fingerprinter for
bridge networks, which is a contstraint checked for if bridge
network is being used. If users upgrade servers first as is
recommended, suddenly no clients running older versions of Nomad
will satisfy the bridge network resource constraint. Instead,
this change only enforces the constraint if the Nomad client
version is also >= 0.12.
Closes#8423
* use msgtype in upsert node
adds message type to signature for upsert node, update tests, remove placeholder method
* UpsertAllocs msg type test setup
* use upsertallocs with msg type in signature
update test usage of delete node
delete placeholder msgtype method
* add msgtype to upsert evals signature, update test call sites with test setup msg type
handle snapshot upsert eval outside of FSM and ignore eval event
remove placeholder upsertevalsmsgtype
handle job plan rpc and prevent event creation for plan
msgtype cleanup upsertnodeevents
updatenodedrain msgtype
msg type 0 is a node registration event, so set the default to the ignore type
* fix named import
* fix signature ordering on upsertnode to match
Fixes#9017
The ?resources=true query parameter includes resources in the object
stub listings. Specifically:
- For `/v1/nodes?resources=true` both the `NodeResources` and
`ReservedResources` field are included.
- For `/v1/allocations?resources=true` the `AllocatedResources` field is
included.
The ?task_states=false query parameter removes TaskStates from
/v1/allocations responses. (By default TaskStates are included.)
* Node Drain events and Node Events (#8980)
Deployment status updates
handle deployment status updates (paused, failed, resume)
deployment alloc health
generate events from apply plan result
txn err check, slim down deployment event
one ndjson line per index
* consolidate down to node event + type
* fix UpdateDeploymentAllocHealth test invocations
* fix test
Fixes a bug where CSI volumes with the `MULTI_NODE_MULTI_WRITER` access mode
were using the same logic as `MULTI_NODE_SINGLE_WRITER` to determine whether
the volume had writer claims available for scheduling.
Extends CSI claim endpoint test to exercise multi-reader and make sure `WriteFreeClaims`
is exercised for multi-writer in feasibility test.
This PR fixes a long standing bug where submitting jobs with changes
to connect services would not trigger updates as expected. Previously,
service blocks were not considered as sources of destructive updates
since they could be synced with consul non-destructively. With Connect,
task group services that have changes to their connect block or to
the service port should be destructive, since the network plumbing of
the alloc is going to need updating.
Fixes#8596#7991
Non-destructive half in #7192
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 handles the case where a job when from no-deployment to deployment
with canaries.
Consider a case where a `max_parallel=0` job is submitted as version 0,
then an update is submitted with `max_parallel=1, canary=1` as verion 1.
In this case, we will have 1 canary alloc, and all remaining allocs will
be version 0. Until the deployment is promoted, we ought to replace the
canaries with version 0 job (which isn't associated with a deployment).
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.
* ar: support opting into binding host ports to default network IP
* fix config plumbing
* plumb node address into network resource
* struct: only handle network resource upgrade path once
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
The BinPackIter accounted for node reservations twice when scoring nodes
which could bias scores toward nodes with reservations.
Pseudo-code for previous algorithm:
```
proposed = reservedResources + sum(allocsResources)
available = nodeResources - reservedResources
score = 1 - (proposed / available)
```
The node's reserved resources are added to the total resources used by
allocations, and then the node's reserved resources are later
substracted from the node's overall resources.
The new algorithm is:
```
proposed = sum(allocResources)
available = nodeResources - reservedResources
score = 1 - (proposed / available)
```
The node's reserved resources are no longer added to the total resources
used by allocations.
My guess as to how this bug happened is that the resource utilization
variable (`util`) is calculated and returned by the `AllocsFit` function
which needs to take reserved resources into account as a basic
feasibility check.
To avoid re-calculating alloc resource usage (because there may be a
large number of allocs), we reused `util` in the `ScoreFit` function.
`ScoreFit` properly accounts for reserved resources by subtracting them
from the node's overall resources. However since `util` _also_ took
reserved resources into account the score would be incorrect.
Prior to the fix the added test output:
```
Node: reserved Score: 1.0000
Node: reserved2 Score: 1.0000
Node: no-reserved Score: 0.9741
```
The scores being 1.0 for *both* nodes with reserved resources is a good
hint something is wrong as they should receive different scores. Upon
further inspection the double accounting of reserved resources caused
their scores to be >1.0 and clamped.
After the fix the added test outputs:
```
Node: no-reserved Score: 0.9741
Node: reserved Score: 0.9480
Node: reserved2 Score: 0.8717
```
Mahmood Ali