Upon dequeuing an evaluation workers snapshot their state store at the
eval's wait index or later. This ensures we process an eval at a point
in time after it was created or updated. Processing an eval on an old
snapshot could cause any number of problems such as:
1. Since job registration atomically updates an eval and job in a single
raft entry, scheduling against indexes before that may not have the
eval's job or may have an older version.
2. The older the scheduler's snapshot, the higher the likelihood
something has changed in the cluster state which will cause the plan
applier to reject the scheduler's plan. This could waste work or
even cause eval's to be failed needlessly.
However, the workers run in parallel with a new server pulling the
cluster state from a peer. During this time, which may be many minutes
long, the state store is likely far behind the minimum index required
to process evaluations.
This PR addresses this by adding an additional long backoff period after
an eval is nacked. If the scheduler's indexes catches up within the
additional backoff, it will unblock early to dequeue the next eval.
When the server shuts down we'll get a `context.Canceled` error from the state
store method. We need to bubble this error up so that other callers can detect
it. Handle this case separately when waiting after dequeue so that we can warn
on shutdown instead of throwing an ambiguous error message with just the text
"canceled."
While there may be more precise ways to block scheduling until the
server catches up, this approach adds little risk and covers additional
cases where a server may be temporarily behind due to a spike in load or
a saturated network.
For testing, we make the `raftSyncLimit` into a parameter on the worker's `run` method
so that we can run backoff tests without waiting 30+ seconds. We haven't followed thru
and made all the worker globals into worker parameters, because there isn't much
use outside of testing, but we can consider that in the future.
Co-authored-by: Tim Gross <tgross@hashicorp.com>
This changeset fixes a long-standing point of confusion in metrics emitted by
the eval broker. The eval broker has a queue of "blocked" evals that are waiting
for an in-flight ("unacked") eval of the same job to be completed. But this
"blocked" state is not the same as the `blocked` status that we write to raft
and expose in the Nomad API to end users. There's a second metric
`nomad.blocked_eval.total_blocked` that refers to evaluations in that
state. This has caused ongoing confusion in major customer incidents and even in
our own documentation! (Fixed in this PR.)
There's little functional change in this PR aside from the name of the metric
emitted, but there's a bit refactoring to clean up the names in `eval_broker.go`
so that there aren't name collisions and multiple names for the same
state. Changes included are:
* Everything that was previously called "pending" referred to entities that were
associated witht he "ready" metric. These are all now called "ready" to match
the metric.
* Everything named "blocked" in `eval_broker.go` is now named "pending", except
for a couple of comments that actually refer to blocked RPCs.
* Added a note to the upgrade guide docs for 1.5.0.
* Fixed the scheduling performance metrics docs because the description for
`nomad.broker.total_blocked` was actually the description for
`nomad.blocked_eval.total_blocked`.
* Add config elements
* Wire in snapshot configuration to raft
* Add hot reload of raft config
* Add documentation for new raft settings
* Add changelog
The description for the `nomad.nomad.blocked_evals.total_blocked` states that this could include evals blocked due to reached quota limits, but the `total_quota_limit` mentions being exclusive to its own metric. I personally interpret `total_blocked` as encompassing any blocked evals for any reason, as written in the docs. Though someone will have to verify the validity of that statement and possibly rectify the other metric description.
Fixed a typo: `limtis` vs `limits`.
* consul: correctly understand missing consul checks as unhealthy
This PR fixes a bug where Nomad assumed any registered Checks would exist
in the service registration coming back from Consul. In some cases, the
Consul may be slow in processing the check registration, and the response
object would not contain checks. Nomad would then scan the empty response
looking for Checks with failing health status, finding none, and then
marking a task/alloc as healthy.
In reality, we must always use Nomad's view of what checks should exist as
the source of truth, and compare that with the response Consul gives us,
making sure they match, before scanning the Consul response for failing
check statuses.
Fixes#15536
* consul: minor CR refactor using maps not sets
* consul: observe transition from healthy to unhealthy checks
* consul: spell healthy correctly
To see why I think this is a good change lets look at why I am making it
My disk was full, which means GC was happening agressively. So by the
time I called the logging endpoint from the SDK, the logs were GC'd
The error I was getting before was:
```
invalid character 'i' in literal false (expecting 'l')
```
Now the error I get is:
```
failed to decode log endpoint response as JSON: "failed to list entries: open /tmp/nomad.data.4219353875/alloc/f11fee50-2b66-a7a2-d3ec-8442cb3d557a/alloc/logs: no such file or directory"
```
Still not super descriptive but much more debugable
The OIDC provider cache is used by the RPC handler as the OIDC
implementation keeps long lived processes running. These process
include connections to the remote OIDC provider.
The Callback server is used by the CLI and starts when the login
command is triggered. This callback server includes success HTML
which is displayed when the user successfully logs into the remote
OIDC provider.
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.
This PR adds support for configuring `proxy.upstreams[].config` for
Consul Connect upstreams. This is an opaque config value to Nomad -
the data is passed directly to Consul and is unknown to Nomad.
* connect: fix non-"tcp" ingress gateway validation
changes apply to http, http2, and grpc:
* if "hosts" is excluded, consul will use its default domain
e.g. <service-name>.ingress.dc1.consul
* can't set hosts with "*" service name
* test http2 and grpc too
* [no ci] first pass at plumbing grpc_ca_file
* consul: add support for grpc_ca_file for tls grpc connections in consul 1.14+
This PR adds client config to Nomad for specifying consul.grpc_ca_file
These changes combined with https://github.com/hashicorp/consul/pull/15913 should
finally enable Nomad users to upgrade to Consul 1.14+ and use tls grpc connections.
* consul: add cl entgry for grpc_ca_file
* docs: mention grpc_tls changes due to Consul 1.14
