Fixes#14617
Dynamic Node Metadata allows Nomad users, and their jobs, to update Node metadata through an API. Currently Node metadata is only reloaded when a Client agent is restarted.
Includes new UI for editing metadata as well.
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Co-authored-by: Phil Renaud <phil.renaud@hashicorp.com>
Also tightens up authentication for these endpoints by enforcing the server
certificate name is valid. We protect these endpoints currently by mTLS and
can't use an auth token because these endpoints are (uniquely) called by the
leader and followers for a given node won't have the leader's ephemeral ACL
token. Add a certificate name check that requests come from a server and not a
client, because no client should ever send these RPCs directly.
* Add config elements
* Wire in snapshot configuration to raft
* Add hot reload of raft config
* Add documentation for new raft settings
* Add changelog
This adds new OIDC endpoints on the RPC endpoint. These two RPCs
handle generating the OIDC provider URL and then completing the
login by exchanging the provider token with an internal Nomad
token.
The RPC endpoints both do double forwarding. The initial forward
is to ensure we are talking to the regional leader; the second
then takes into account whether the auth method generates local or
global tokens. If it creates global tokens, we must then forward
onto the federated regional leader.
Streaming RPCs should only be registered once, not on every RPC call, because they set keys in StreamingRpcRegistry.registry map. This PR fixes it by checking whether endpoints are already registered before calling .register() method. Fixes#15474
Co-authored-by: Tim Gross <tgross@hashicorp.com>
Nomad server components that aren't in the `nomad` package like the deployment
watcher and volume watcher need to make RPC calls but can't import the Server
struct to do so because it creates a circular reference. These components have a
"shim" object that gets populated to pass a "static" handler that has no RPC
context.
Most RPC handlers are never used in this way, but during server setup we were
constructing a set of static handlers for most RPC endpoints anyways. This is
slightly wasteful but also confusing to developers who end up being encouraged
to just copy what was being done for previous RPCs.
This changeset includes the following refactorings:
* Remove the static handlers field on the server
* Instead construct just the specific static handlers we need to pass into the
deployment watcher and volume watcher.
* Remove the unnecessary static handler from heartbeater
* Update various tests to avoid needing the static endpoints and have them use a
endpoint constructed on the spot.
Follow-up work will examine whether we can remove the RPCs from deployment
watcher and volume watcher entirely, falling back to raft applies like node
drainer does currently.
In #15430 we refactored the RPC endpoint configuration to make adding the RPC
context easier. But when implementing the change on the Enterprise side, I
discovered that the registration of enterprise endpoints was being done
incorrectly -- this doesn't show up on OSS because the registration is always a
no-op here.
Upcoming work to instrument the rate of RPC requests by consumer (and eventually
rate limit) requires that we thread the `RPCContext` through all RPC
handlers so that we can access the underlying connection. This changeset adds
the context to everywhere we intend to initially support it and intentionally
excludes streaming RPCs and client RPCs.
To improve the ergonomics of adding the context everywhere its needed and to
clarify the requirements of dynamic vs static handlers, I've also done a good
bit of refactoring here:
* canonicalized the RPC handler fields so they're as close to identical as
possible without introducing unused fields (i.e. I didn't add loggers if the
handler doesn't use them already).
* canonicalized the imports in the handler files.
* added a `NewExampleEndpoint` function for each handler that ensures we're
constructing the handlers with the required arguments.
* reordered the registration in server.go to match the order of the files (to
make it easier to see if we've missed one), and added a bunch of commentary
there as to what the difference between static and dynamic handlers is.
When an evaluation is acknowledged by a scheduler, the resulting plan is
guaranteed to cover up to the `waitIndex` set by the worker based on the most
recent evaluation for that job in the state store. At that point, we no longer
need to retain blocked evaluations in the broker that are older than that index.
Move all but the highest priority / highest `ModifyIndex` blocked eval into a
canceled set. When the `Eval.Ack` RPC returns from the eval broker it will
signal a reap of a batch of cancelable evals to write to raft. This paces the
cancelations limited by how frequently the schedulers are acknowledging evals;
this should reduce the risk of cancelations from overwhelming raft relative to
scheduler progress. In order to avoid straggling batches when the cluster is
quiet, we also include a periodic sweep through the cancelable list.
Nomad's original autopilot was importing from a private package in Consul. It
has been moved out to a shared library. Switch Nomad to use this library so that
we can eliminate the import of Consul, which is necessary to build Nomad ENT
with the current version of the Consul SDK. This also will let us pick up
autopilot improvements shared with Consul more easily.
Plan rejections occur when the scheduler work and the leader plan
applier disagree on the feasibility of a plan. This may happen for valid
reasons: since Nomad does parallel scheduling, it is expected that
different workers will have a different state when computing placements.
As the final plan reaches the leader plan applier, it may no longer be
valid due to a concurrent scheduling taking up intended resources. In
these situations the plan applier will notify the worker that the plan
was rejected and that they should refresh their state before trying
again.
In some rare and unexpected circumstances it has been observed that
workers will repeatedly submit the same plan, even if they are always
rejected.
While the root cause is still unknown this mitigation has been put in
place. The plan applier will now track the history of plan rejections
per client and include in the plan result a list of node IDs that should
be set as ineligible if the number of rejections in a given time window
crosses a certain threshold. The window size and threshold value can be
adjusted in the server configuration.
To avoid marking several nodes as ineligible at one, the operation is rate
limited to 5 nodes every 30min, with an initial burst of 10 operations.
In order to support implicit ACL policies for tasks to get their own
secrets, each task would need to have its own ACL token. This would
add extra raft overhead as well as new garbage collection jobs for
cleaning up task-specific ACL tokens. Instead, Nomad will create a
workload Identity Claim for each task.
An Identity Claim is a JSON Web Token (JWT) signed by the server’s
private key and attached to an Allocation at the time a plan is
applied. The encoded JWT can be submitted as the X-Nomad-Token header
to replace ACL token secret IDs for the RPCs that support identity
claims.
Whenever a key is is added to a server’s keyring, it will use the key
as the seed for a Ed25519 public-private private keypair. That keypair
will be used for signing the JWT and for verifying the JWT.
This implementation is a ruthlessly minimal approach to support the
secure variables feature. When a JWT is verified, the allocation ID
will be checked against the Nomad state store, and non-existent or
terminal allocation IDs will cause the validation to be rejected. This
is sufficient to support the secure variables feature at launch
without requiring implementation of a background process to renew
soon-to-expire tokens.
Replication for the secure variables keyring. Because only key
metadata is stored in raft, we need to distribute key material
out-of-band from raft replication. A goroutine runs on each server and
watches for changes to the `RootKeyMeta`. When a new key is received,
attempt to fetch the key from the leader. If the leader doesn't have
the key (which may happen if a key is rotated right before a leader
transition), try to get the key from any peer.
When a server becomes leader, it will check if there are any keys in
the state store, and create one if there is not. The key metadata will
be replicated via raft to all followers, who will then get the key
material via key replication (not implemented in this changeset).
This changeset implements the keystore serialization/deserialization:
* Adds a JSON serialization extension for the `RootKey` struct, along with a metadata stub. When we serialize RootKey to the on-disk keystore, we want to base64 encode the key material but also exclude any frequently-changing fields which are stored in raft.
* Implements methods for loading/saving keys to the keystore.
* Implements methods for restoring the whole keystore from disk.
* Wires it all up with the `Keyring` RPC handlers and fixes up any fallout on tests.
* core: allow pause/un-pause of eval broker on region leader.
* agent: add ability to pause eval broker via scheduler config.
* cli: add operator scheduler commands to interact with config.
* api: add ability to pause eval broker via scheduler config
* e2e: add operator scheduler test for eval broker pause.
* docs: include new opertor scheduler CLI and pause eval API info.
Revert a small part of #11600 after @lgfa29 discovered it would break
compatibility with Nomad <= v1.2!
Nomad <= v1.2 expects the `vsn` tag to exist in Serf. It has always been
`1`. It has no functional purpose. However it causes a parsing error if
it is not set:
https://github.com/hashicorp/nomad/blob/v1.2.6/nomad/util.go#L103-L108
This means Nomad servers at version v1.2 or older will not allow servers
without this tag to join.
The `mvn` minor version tag is also checked, but soft fails. I'm not
setting that because I want as much of this cruft gone as possible.
Downgrading the Raft version protocol is not a supported operation.
Checking for a downgrade is hard since this information is not stored in
any persistent place. When a server re-joins a cluster with a prior Raft
version, the Serf tag is updated so Nomad can't tell that the version
changed.
Mixed version clusters must be supported to allow for zero-downtime
rolling upgrades. During this it's expected that the cluster will have
mixed Raft versions. Enforcing consistency strong version consistency
would disrupt this flow.
The approach taken here is to store the Raft version on disk. When the
server starts the `raft_protocol` value is written to the file
`data_dir/raft/version`. If that file already exists, its content is
checked against the current `raft_protocol` value to detect downgrades
and prevent the server from starting.
Any other types of errors are ignore to prevent disruptions that are
outside the control of operators. The only option in cases of an invalid
or corrupt file would be to delete it, making this check useless. So
just overwrite its content with the new version and provide guidance on
how to check that their cluster is an expected state.
Nomad inherited protocol version numbering configuration from Consul and
Serf, but unlike those projects Nomad has never used it. Nomad's
`protocol_version` has always been `1`.
While the code is effectively unused and therefore poses no runtime
risks to leave, I felt like removing it was best because:
1. Nomad's RPC subsystem has been able to evolve extensively without
needing to increment the version number.
2. Nomad's HTTP API has evolved extensively without increment
`API{Major,Minor}Version`. If we want to version the HTTP API in the
future, I doubt this is the mechanism we would choose.
3. The presence of the `server.protocol_version` configuration
parameter is confusing since `server.raft_protocol` *is* an important
parameter for operators to consider. Even more confusing is that
there is a distinct Serf protocol version which is included in `nomad
server members` output under the heading `Protocol`. `raft_protocol`
is the *only* protocol version relevant to Nomad developers and
operators. The other protocol versions are either deadcode or have
never changed (Serf).
4. If we were to need to version the RPC, HTTP API, or Serf protocols, I
don't think these configuration parameters and variables are the best
choice. If we come to that point we should choose a versioning scheme
based on the use case and modern best practices -- not this 6+ year
old dead code.
This PR replaces use of time.After with a safe helper function
that creates a time.Timer to use instead. The new function returns
both a time.Timer and a Stop function that the caller must handle.
Unlike time.NewTimer, the helper function does not panic if the duration
set is <= 0.
## Development Environment Changes
* Added stringer to build deps
## New HTTP APIs
* Added scheduler worker config API
* Added scheduler worker info API
## New Internals
* (Scheduler)Worker API refactor—Start(), Stop(), Pause(), Resume()
* Update shutdown to use context
* Add mutex for contended server data
- `workerLock` for the `workers` slice
- `workerConfigLock` for the `Server.Config.NumSchedulers` and
`Server.Config.EnabledSchedulers` values
## Other
* Adding docs for scheduler worker api
* Add changelog message
Co-authored-by: Derek Strickland <1111455+DerekStrickland@users.noreply.github.com>
James Rasell