This change modifies the Nomad job register and deregister RPCs to
accept an updated option set which includes eval priority. This
param is optional and override the use of the job priority to set
the eval priority.

In order to ensure all evaluations as a result of the request use
the same eval priority, the priority is shared to the
allocReconciler and deploymentWatcher. This creates a new
distinction between eval priority and job priority.

The Nomad agent HTTP API has been modified to allow setting the
eval priority on job update and delete. To keep consistency with
the current v1 API, job update accepts this as a payload param;
job delete accepts this as a query param.

Any user supplied value is validated within the agent HTTP handler
removing the need to pass invalid requests to the server.

The register and deregister opts functions now all for setting
the eval priority on requests.

The change includes a small change to the DeregisterOpts function
which handles nil opts. This brings the function inline with the
RegisterOpts.

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...

1.1.3 had a bug where task.VolumeMounts will be an empty slice instead of nil. Eventually, it gets canonicalized and is set to `nil`, but it seems to confuse dry-run planning.

The regression was introduced in https://github.com/hashicorp/nomad/pull/10855/files#diff-56b3c82fcbc857f8fb93a903f1610f6e6859b3610a4eddf92bad9ea27fdc85ecL1028-R1037 . Curiously, it's the only place where `len(apiTask.VolumeMounts)` check was dropped. I assume it was dropped accidentally.

Fixes #10981

When a jobspec doesn't include a namespace, we provide it with the default
namespace, but this ends up overriding the explicit `-namespace` flag. This
changeset uses the same logic as region parsing to create an order of
precedence: the query string parameter (the `-namespace` flag) overrides the
API request body which overrides the jobspec.

This PR fixes some job submission plumbing to make sure the Consul Check parameters
- failure_before_critical
- success_before_passing

work with group-level services. They already work with task-level services.

This PR implements first-class support for Nomad running Consul
Connect Mesh Gateways. Mesh gateways enable services in the Connect
mesh to make cross-DC connections via gateways, where each datacenter
may not have full node interconnectivity.

Consul docs with more information:
https://www.consul.io/docs/connect/gateways/mesh-gateway

The following group level service block can be used to establish
a Connect mesh gateway.

service {
  connect {
    gateway {
      mesh {
        // no configuration
      }
    }
  }
}

Services can make use of a mesh gateway by configuring so in their
upstream blocks, e.g.

service {
  connect {
    sidecar_service {
      proxy {
        upstreams {
          destination_name = "<service>"
          local_bind_port  = <port>
          datacenter       = "<datacenter>"
          mesh_gateway {
            mode = "<mode>"
          }
        }
      }
    }
  }
}

Typical use of a mesh gateway is to create a bridge bet...

ParentID is an internal field that Nomad sets for dispatched or parameterized jobs. Job submitters should not be able to set it directly, as that messes up children tracking.

Fixes #10422 . It specifically stops the scheduler from honoring the ParentID. The reason failure and why the scheduler didn't schedule that job once it was created is very interesting and requires follow up with a more technical issue.

Consul allows specifying the HTTP body to send in a health check. Nomad
uses Consul for health checking so this just plumbs the value through to
where the Consul API is called.

There is no validation that `body` is not used with an incompatible
check method like GET.

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.

This commit updates the API to pass the MemoryMaxMB field, and the CLI to show
the max set for the task.

Also, start parsing the MemoryMaxMB in hcl2, as it's set by tags.

A sample CLI output; note the additional `Max: ` for "task":

```
$ nomad alloc status 96fbeb0b
ID                  = 96fbeb0b-a0b3-aa95-62bf-b8a39492fd5c
[...]

Task "cgroup-fetcher" is "running"
Task Resources
CPU        Memory         Disk     Addresses
0/500 MHz  32 MiB/20 MiB  300 MiB

Task Events:
[...]

Task "task" is "running"
Task Resources
CPU        Memory          Disk     Addresses
0/500 MHz  176 KiB/20 MiB  300 MiB
           Max: 30 MiB

Task Events:
[...]
```

Allow for readiness type checks by configuring nomad to ignore warnings
or errors reported by a service check. This allows the deployment to
progress and while Consul handles introducing the sercive into a
resource pool once the check passes.

This PR implements Nomad built-in support for running Consul Connect
terminating gateways. Such a gateway can be used by services running
inside the service mesh to access "legacy" services running outside
the service mesh while still making use of Consul's service identity
based networking and ACL policies.

https://www.consul.io/docs/connect/gateways/terminating-gateway

These gateways are declared as part of a task group level service
definition within the connect stanza.

service {
  connect {
    gateway {
      proxy {
        // envoy proxy configuration
      }
      terminating {
        // terminating-gateway configuration entry
      }
    }
  }
}

Currently Envoy is the only supported gateway implementation in
Consul. The gateay task can be customized by configuring the
connect.sidecar_task block.

When the gateway.terminating field is set, Nomad will write/update
the Configuration Entry into Consul on job submission. Because CEs
are global in scope and there may be more than one Nomad cluster
communicating with Consul, there is an assumption that any terminating
gateway defined in Nomad for a particular service will be the same
among Nomad clusters.

Gateways require Consul 1.8.0+, checked by a node constraint.

Closes #9445

Before, upstreams could only be defined using the default datacenter.
Now, the `datacenter` field can be set in a connect upstream definition,
informing consul of the desire for an instance of the upstream service
in the specified datacenter. The field is optional and continues to
default to the local datacenter.

Closes #8964

This PR adds the ability to set HTTP headers when downloading
an artifact from an `http` or `https` resource.

The implementation in `go-getter` is such that a new `HTTPGetter`
must be created for each artifact that sets headers (as opposed
to conveniently setting headers per-request). This PR maintains
the memoization of the default Getter objects, creating new ones
only for artifacts where headers are set.

Closes #9306

* 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

Since CPU resources are usually a soft limit it is desirable to allow
setting it as low as possible to allow tasks to run only in "idle" time.

Setting it to 0 is still not allowed to avoid potential unintentional
side effects with allowing a zero value. While there may not be any side
effects this commit attempts to minimize risk by avoiding the issue.

This does *not* change the defaults.

This change adds the ability to set the fields `success_before_passing` and
`failures_before_critical` on Consul service check definitions. This is a
feature added to Consul v1.7.0 and later.
  https://www.consul.io/docs/agent/checks#success-failures-before-passing-critical

Nomad doesn't do much besides pass the fields through to Consul.

Fixes #6913

adds in oss components to support enterprise multi-vault namespace feature

upgrade specific doc on vault multi-namespaces

vault docs

update test to reflect new error

This PR adds the capability of running Connect Native Tasks on Nomad,
particularly when TLS and ACLs are enabled on Consul.

The `connect` stanza now includes a `native` parameter, which can be
set to the name of task that backs the Connect Native Consul service.

There is a new Client configuration parameter for the `consul` stanza
called `share_ssl`. Like `allow_unauthenticated` the default value is
true, but recommended to be disabled in production environments. When
enabled, the Nomad Client's Consul TLS information is shared with
Connect Native tasks through the normal Consul environment variables.
This does NOT include auth or token information.

If Consul ACLs are enabled, Service Identity Tokens are automatically
and injected into the Connect Native task through the CONSUL_HTTP_TOKEN
environment variable.

Any of the automatically set environment variables can be overridden by
the Connect Native task using the `env` stanza.

Fixes #6083

This reverts the introduction of AllNamespaces parameter that was merged
earlier but never got released.

Initial struct definitions, jobspec parsing, validation, and conversion
between Nomad structs and API structs for multi-region deployments.

Allow a `/v1/jobs?all_namespaces=true` to list all jobs across all
namespaces.  The returned list is to contain a `Namespace` field
indicating the job namespace.

If ACL is enabled, the request token needs to be a management token or
have `namespace:list-jobs` capability on all existing namespaces.

updated ScalingEvent API to record "message string,error bool" instead
of confusing "reason,error *string"

Enable configuration of HTTP and gRPC endpoints which should be exposed by
the Connect sidecar proxy. This changeset is the first "non-magical" pass
that lays the groundwork for enabling Consul service checks for tasks
running in a network namespace because they are Connect-enabled. The changes
here provide for full configuration of the

  connect {
    sidecar_service {
      proxy {
        expose {
          paths = [{
		path = <exposed endpoint>
                protocol = <http or grpc>
                local_path_port = <local endpoint port>
                listener_port = <inbound mesh port>
	  }, ... ]
       }
    }
  }

stanza. Everything from `expose` and below is new, and partially implements
the precedent set by Consul:
  https://www.consul.io/docs/connect/registration/service-registration.html#expose-paths-configuration-reference

Combined with a task-group level network port-mapping in the form:

  port "exposeExample" { to = -1 }

it is now pos...

added ACL protection in Job.Scale
in Job.Scale, only perform a Job.Register if the Count was non-nil