This PR adds support for the raw_exec driver on systems with only cgroups v2.
The raw exec driver is able to use cgroups to manage processes. This happens
only on Linux, when exec_driver is enabled, and the no_cgroups option is not
set. The driver uses the freezer controller to freeze processes of a task,
issue a sigkill, then unfreeze. Previously the implementation assumed cgroups
v1, and now it also supports cgroups v2.
There is a bit of refactoring in this PR, but the fundamental design remains
the same.
Closes#12351#12348
The volume watcher design was based on deploymentwatcher and drainer,
but has an important difference: we don't want to maintain a goroutine
for the lifetime of the volume. So we stop the volumewatcher goroutine
for a volume when that volume has no more claims to free. But the
shutdown races with updates on the parent goroutine, and it's possible
to drop updates. Fortunately these updates are picked up on the next
core GC job, but we're most likely to hit this race when we're
replacing an allocation and that's the time we least want to wait.
Wait until the volume has "settled" before stopping this goroutine so
that the race between shutdown and the parent goroutine sending on
`<-updateCh` is pushed to after the window we most care about quick
freeing of claims.
* Fixes a resource leak when volumewatchers are no longer needed. The
volume is nil and can't ever be started again, so the volume's
`watcher` should be removed from the top-level `Watcher`.
* De-flakes the GC job test: the test throws an error because the
claimed node doesn't exist and is unreachable. This flaked instead of
failed because we didn't correctly wait for the first pass through the
volumewatcher.
Make the GC job wait for the volumewatcher to reach the quiescent
timeout window state before running the GC eval under test, so that
we're sure the GC job's work isn't being picked up by processing one
of the earlier claims. Update the claims used so that we're sure the
GC pass won't hit a node unpublish error.
* Adds trace logging to unpublish operations
* lint: require should not be aliased in core_sched_test
* lint: require should not be aliased in volumes_watcher_test
* testing: don't alias state package in core_sched_test
In #12112 and #12113 we solved for the problem of races in releasing
volume claims, but there was a case that we missed. During a node
drain with a controller attach/detach, we can hit a race where we call
controller publish before the unpublish has completed. This is
discouraged in the spec but plugins are supposed to handle it
safely. But if the storage provider's API is slow enough and the
plugin doesn't handle the case safely, the volume can get "locked"
into a state where the provider's API won't detach it cleanly.
Check the claim before making any external controller publish RPC
calls so that Nomad is responsible for the canonical information about
whether a volume is currently claimed.
This has a couple side-effects that also had to get fixed here:
* Changing the order means that the volume will have a past claim
without a valid external node ID because it came from the client, and
this uncovered a separate bug where we didn't assert the external node
ID was valid before returning it. Fallthrough to getting the ID from
the plugins in the state store in this case. We avoided this
originally because of concerns around plugins getting lost during node
drain but now that we've fixed that we may want to revisit it in
future work.
* We should make sure we're handling `FailedPrecondition` cases from
the controller plugin the same way we handle other retryable cases.
* Several tests had to be updated because they were assuming we fail
in a particular order that we're no longer doing.
* csi: resolve invalid claim states on read
It's currently possible for CSI volumes to be claimed by allocations
that no longer exist. This changeset asserts a reasonable state at
the state store level by registering these nil allocations as "past
claims" on any read. This will cause any pass through the periodic GC
or volumewatcher to trigger the unpublishing workflow for those claims.
* csi: make feasibility check errors more understandable
When the feasibility checker finds we have no free write claims, it
checks to see if any of those claims are for the job we're currently
scheduling (so that earlier versions of a job can't block claims for
new versions) and reports a conflict if the volume can't be scheduled
so that the user can fix their claims. But when the checker hits a
claim that has a GCd allocation, the state is recoverable by the
server once claim reaping completes and no user intervention is
required; the blocked eval should complete. Differentiate the
scheduler error produced by these two conditions.
* 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
If a core job fails more than the delivery limit, the leader will create a new
eval with the TriggeredBy field set to `failed-follow-up`.
Evaluations for core jobs have the leader's ACL, which is not valid on another
leader after an election. The `failed-follow-up` evals do not have ACLs, so
core job evals that fail more than the delivery limit or core job evals that
span leader elections will never succeed and will be re-enqueued forever. So
we should not retry with a `failed-follow-up`.
This changeset updates `nomad/volumewatcher` to take advantage of the
`CSIVolume.Unpublish` RPC. This lets us eliminate a bunch of code and
associated tests. The raft batching code can be safely dropped, as the
characteristic times of the CSI RPCs are on the order of seconds or even
minutes, so batching up raft RPCs added complexity without any real world
performance wins.
Includes refactor w/ test cleanup and dead code elimination in volumewatcher
This changeset implements a periodic garbage collection of CSI volumes
with missing allocations. This can happen in a scenario where a node
update fails partially and the allocation updates are written to raft
but the evaluations to GC the volumes are dropped. This feature will
cover this edge case and ensure that upgrades from 0.11.0 and 0.11.1
get any stray claims cleaned up.
This changeset implements a periodic garbage collection of unused CSI
plugins. Plugins are self-cleaning when the last allocation for a
plugin is stopped, but this feature will cover any missing edge cases
and ensure that upgrades from 0.11.0 and 0.11.1 get any stray plugins
cleaned up.
This changeset adds a subsystem to run on the leader, similar to the
deployment watcher or node drainer. The `Watcher` performs a blocking
query on updates to the `CSIVolumes` table and triggers reaping of
volume claims.
This will avoid tying up scheduling workers by immediately sending
volume claim workloads into their own loop, rather than blocking the
scheduling workers in the core GC job doing things like talking to CSI
controllers
The volume watcher is enabled on leader step-up and disabled on leader
step-down.
The volume claim GC mechanism now makes an empty claim RPC for the
volume to trigger an index bump. That in turn unblocks the blocking
query in the volume watcher so it can assess which claims can be
released for a volume.
Adds a `CSIVolumeClaim` type to be tracked as current and past claims
on a volume. Allows for a client RPC failure during node or controller
detachment without having to keep the allocation around after the
first garbage collection eval.
This changeset lays groundwork for moving the actual detachment RPCs
into a volume watching loop outside the GC eval.
The CSI plugins uses the external volume ID for all operations, but
the Client CSI RPCs uses the Nomad volume ID (human-friendly) for the
mount paths. Pass the External ID as an arg in the RPC call so that
the unpublish workflows have it without calling back to the server to
find the external ID.
The controller CSI plugins need the CSI node ID (or in other words,
the storage provider's view of node ID like the EC2 instance ID), not
the Nomad node ID, to determine how to detach the external volume.
* nomad/state/state_store: error message copy/paste error
* nomad/structs/structs: add a VolumeEval to the JobDeregisterResponse
* nomad/job_endpoint: synchronously, volumeClaimReap on job Deregister
* nomad/core_sched: make volumeClaimReap available without a CoreSched
* nomad/job_endpoint: Deregister return early if the job is missing
* nomad/job_endpoint_test: job Deregistion is idempotent
* nomad/core_sched: conditionally ignore alloc status in volumeClaimReap
* nomad/job_endpoint: volumeClaimReap all allocations, even running
* nomad/core_sched_test: extra argument to collectClaimsToGCImpl
* nomad/job_endpoint: job deregistration is not idempotent
If a volume-claiming alloc stops and the CSI Node plugin that serves
that alloc's volumes is missing, there's no way for the allocrunner
hook to send the `NodeUnpublish` and `NodeUnstage` RPCs.
This changeset addresses this issue with a redesign of the client-side
for CSI. Rather than unmounting in the alloc runner hook, the alloc
runner hook will simply exit. When the server gets the
`Node.UpdateAlloc` for the terminal allocation that had a volume claim,
it creates a volume claim GC job. This job will made client RPCs to a
new node plugin RPC endpoint, and only once that succeeds, move on to
making the client RPCs to the controller plugin. If the node plugin is
unavailable, the GC job will fail and be requeued.
* acl/policy: add the volume ACL policies
* nomad/csi_endpoint: enforce ACLs for volume access
* nomad/search_endpoint_oss: volume acls
* acl/acl: add plugin read as a global policy
* acl/policy: add PluginPolicy global cap type
* nomad/csi_endpoint: check the global plugin ACL policy
* nomad/mock/acl: PluginPolicy
* nomad/csi_endpoint: fix list rebase
* nomad/core_sched_test: new test since #7358
* nomad/csi_endpoint_test: use correct permissions for list
* nomad/csi_endpoint: allowCSIMount keeps ACL checks together
* nomad/job_endpoint: check mount permission for jobs
* nomad/job_endpoint_test: need plugin read, too
* nomad/state/schema: use the namespace compound index
* scheduler/scheduler: CSIVolumeByID interface signature namespace
* scheduler/stack: SetJob on CSIVolumeChecker to capture namespace
* scheduler/feasible: pass the captured namespace to CSIVolumeByID
* nomad/state/state_store: use namespace in csi_volume index
* nomad/fsm: pass namespace to CSIVolumeDeregister & Claim
* nomad/core_sched: pass the namespace in volumeClaimReap
* nomad/node_endpoint_test: namespaces in Claim testing
* nomad/csi_endpoint: pass RequestNamespace to state.*
* nomad/csi_endpoint_test: appropriately failed test
* command/alloc_status_test: appropriately failed test
* node_endpoint_test: avoid notTheNamespace for the job
* scheduler/feasible_test: call SetJob to capture the namespace
* nomad/csi_endpoint: ACL check the req namespace, query by namespace
* nomad/state/state_store: remove deregister namespace check
* nomad/state/state_store: remove unused CSIVolumes
* scheduler/feasible: CSIVolumeChecker SetJob -> SetNamespace
* nomad/csi_endpoint: ACL check
* nomad/state/state_store_test: remove call to state.CSIVolumes
* nomad/core_sched_test: job namespace match so claim gc works
This changeset implements the remaining controller detach RPCs: server-to-client and client-to-controller. The tests also uncovered a bug in our RPC for claims which is fixed here; the volume claim RPC is used for both claiming and releasing a claim on a volume. We should only submit a controller publish RPC when the claim is new and not when it's being released.
When an alloc is marked terminal (and after node unstage/unpublish
have been called), the client syncs the terminal alloc state with the
server via `Node.UpdateAlloc RPC`.
For each job that has a terminal alloc, the `Node.UpdateAlloc` RPC
handler at the server will emit an eval for a new core job to garbage
collect CSI volume claims. When this eval is handled on the core
scheduler, it will call a `volumeReap` method to release the claims
for all terminal allocs on the job.
The volume reap will issue a `ControllerUnpublishVolume` RPC for any
node that has no alloc claiming the volume. Once this returns (or
is skipped), the volume reap will send a new `CSIVolume.Claim` RPC
that releases the volume claim for that allocation in the state store,
making it available for scheduling again.
This same `volumeReap` method will be called from the core job GC,
which gives us a second chance to reclaim volumes during GC if there
were controller RPC failures.
This changeset adds a new core job `CoreJobCSIVolumePublicationGC` to
the leader's loop for scheduling core job evals. Right now this is an
empty method body without even a config file stanza. Later changesets
will implement the logic of volume publication GC.
Copy the updated version of freeport (sdk/freeport), and tweak it for use
in Nomad tests. This means staying below port 10000 to avoid conflicts with
the lib/freeport that is still transitively used by the old version of
consul that we vendor. Also provide implementations to find ephemeral ports
of macOS and Windows environments.
Ports acquired through freeport are supposed to be returned to freeport,
which this change now also introduces. Many tests are modified to include
calls to a cleanup function for Server objects.
This should help quite a bit with some flakey tests, but not all of them.
Our port problems will not go away completely until we upgrade our vendor
version of consul. With Go modules, we'll probably do a 'replace' to swap
out other copies of freeport with the one now in 'nomad/helper/freeport'.
This PR fixes an edge case where we could GC an allocation that was in a
desired stop state but had not terminated yet. This can be hit if the
client hasn't shutdown the allocation yet or if the allocation is still
shutting down (long kill_timeout).
Fixes https://github.com/hashicorp/nomad/issues/4940
Seth Hoenig