improve spread docs

website/source/docs/job-specification/group.html.md

@@ -38,6 +38,11 @@ job "docs" {
 - `affinity` <code>([Affinity][]: nil)</code> - This can be provided
     multiple times to define preferred placement criteria.
 
+- `spread` <code>([Spread][spread]: nil)</code> - This can be provided
+  multiple times to define criteria for spreading allocations across a
+  node attribute or metadata. See the
+  [Nomad spread reference](/docs/job-specification/spread.html) for more details.
+
 - `count` `(int: 1)` - Specifies the number of the task groups that should
   be running under this group. This value must be non-negative.
 
@@ -121,6 +126,7 @@ group "example" {
 [task]: /docs/job-specification/task.html "Nomad task Job Specification"
 [job]: /docs/job-specification/job.html "Nomad job Job Specification"
 [constraint]: /docs/job-specification/constraint.html "Nomad constraint Job Specification"
+[spread]: /docs/job-specification/spread.html "Nomad spread Job Specification"
 [affinity]: /docs/job-specification/affinity.html "Nomad affinity Job Specification"
 [ephemeraldisk]: /docs/job-specification/ephemeral_disk.html "Nomad ephemeral_disk Job Specification"
 [meta]: /docs/job-specification/meta.html "Nomad meta Job Specification"

website/source/docs/job-specification/job.html.md

@@ -80,6 +80,10 @@ job "docs" {
     [Nomad affinity reference](/docs/job-specification/affinity.html) for more
     details.
 
+- `spread` <code>([Spread][spread]: nil)</code> - This can be provided multiple times
+  to define criteria for spreading allocations across a node attribute or metadata.
+  See the [Nomad spread reference](/docs/job-specification/spread.html) for more details.
+
 - `datacenters` `(array<string>: <required>)` - A list of datacenters in the region which are eligible
   for task placement. This must be provided, and does not have a default.
 
@@ -230,6 +234,7 @@ $ VAULT_TOKEN="..." nomad job run example.nomad
 
 [constraint]: /docs/job-specification/constraint.html "Nomad constraint Job Specification"
 [affinity]: /docs/job-specification/affinity.html "Nomad affinity Job Specification"
+[spread]: /docs/job-specification/spread.html "Nomad spread Job Specification"
 [group]: /docs/job-specification/group.html "Nomad group Job Specification"
 [meta]: /docs/job-specification/meta.html "Nomad meta Job Specification"
 [migrate]: /docs/job-specification/migrate.html "Nomad migrate Job Specification"

website/source/docs/job-specification/spread.html.md

@@ -29,6 +29,29 @@ The operator can specify a node attribute such as datacenter, availability zone,
 in a physical datacenter to spread the allocations over. By default, when using spread the scheduler will attempt to place allocations equally
 among the available values of the given target.
 
+
+```hcl
+job "docs" {
+  # Spread allocations over all datacenter
+  spread {
+    attribute = "${node.datacenter}"
+  }
+
+  group "example" {
+    # Spread allocations over each rack based on desired percentage
+      spread {
+        attribute = "${node.datacenter}"
+        target "us-east1" {
+          percent = 60
+        }
+        target "us-west1" {
+          percent = 40
+        }
+      }
+  }
+}
+```
+
 Nodes are scored according to how closely they match the desired target percentage defined in the
 spread stanza. Spread scores are combined with other scoring factors such as bin packing.
 
@@ -38,8 +61,7 @@ Spread criteria are treated as a soft preference by the Nomad scheduler.
 If no nodes match a given spread criteria, placement is still successful.
 
 Spread may be expressed on [attributes][interpolation] or [client metadata][client-meta].
-Additionally, spread may be specified at the [job][job], [group][group], or
-[task][task] levels for ultimate flexibility.
+Additionally, spread may be specified at the [job][job] and [group][group] levels for ultimate flexibility.
 
 
 ## `spread` Parameters