[DOCFIX] Update k8s doc with new Helm additions

### What changes were proposed in this pull request?
This PR proposes some additions to the [Alluxio k8s
guide](https://docs.alluxio.io/os/user/stable/en/deploy/Running-Alluxio-On-Kubernetes.html)
to reflect some of the recent additions to the Alluxio Helm chart:

- `serviceAccount`: #13297
- `tolerations`: #13214
- `hostAliases`: #13226
- `strategy`: #13423

### Why are the changes needed?
Doc validation

### Does this PR introduce _any_ user-facing change?
Yes, the documentation.

pr-link: #13579
change-id: cid-cd456e708547bb121cdab5df1de7599860e6e089

docs/en/deploy/Running-Alluxio-On-Kubernetes.md

@@ -1364,9 +1364,15 @@ and `volumeMounts` of each container if existing.
 {% endnavtab %}
 {% endnavtabs %}
 
-### Configuring ServiceAccounts
+### Kubernetes Configuration Options
 
-By default Kubernetes will assign the namespace's `default` ServiceAccount
+The following options are provided in our Helm chart as additional
+parameters for experienced Kubernetes users.
+
+#### ServiceAccounts
+
+[By default](https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/#use-the-default-service-account-to-access-the-api-server)
+Kubernetes will assign the namespace's `default` ServiceAccount
 to new pods in a namespace. You may specify for Alluxio pods to use
 any existing ServiceAccounts you may have in your cluster through
 the following:
@@ -1409,6 +1415,164 @@ spec:
 {% endnavtab %}
 {% endnavtabs %}
 
+#### Node Selectors & Tolerations
+
+Kubernetes provides many options to control the scheduling of pods
+onto nodes in the cluster. The most direct of which is a
+[node selector](https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#nodeselector).
+
+However, Kubernetes will avoid scheduling pods on any tainted nodes.
+To allow certain pods to schedule on such nodes, Kubernetes allows
+you to specify tolerations for those taints. See
+[the Kubernetes documentation on taints and tolerations](https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/)
+for more details.
+
+{% navtabs selectorsTolerations %}
+{% navtab helm %}
+
+You may specify a node selector in JSON as a top-level Helm value,
+`nodeSelector`, which will apply to all pods in the chart. Similarly,
+you may specify a list of tolerations in JSON as a top-level Helm value,
+`tolerations`, which will also apply to all pods in the chart.
+```properties
+nodeSelector: {"app": "alluxio"}
+
+tolerations: [ {"key": "env", "operator": "Equal", "value": "prod", "effect": "NoSchedule"} ]
+```
+
+You can **override** the top-level `nodeSelector` by specifying a value
+for the specific component's `nodeSelector`.
+```properties
+master:
+  nodeSelector: {"app": "alluxio-master"}
+
+worker:
+  nodeSelector: {"app": "alluxio-worker"}
+```
+
+You can **append** to the top-level `tolerations` by specifying a value
+for the specific component's `tolerations`.
+```properties
+logserver:
+  tolerations: [ {"key": "app", "operator": "Equal", "value": "logging", "effect": "NoSchedule"} ]
+```
+
+{% endnavtab %}
+{% navtab kubectl %}
+
+You may add `nodeSelector` and `tolerations` fields to any of the Alluxio Pod template
+specs. For example:
+```properties
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: alluxio-master
+spec:
+  template:
+    spec:
+      nodeSelector:
+        app: alluxio
+      tolerations:
+        - effect: NoSchedule
+          key: env
+          operator: Equal
+          value: prod
+```
+
+{% endnavtab %}
+{% endnavtabs %}
+
+#### Host Aliases
+
+If you wish to add or override hostname resolution in the pods,
+Kubernetes exposes the containers' `/etc/hosts` file via
+[host aliases](https://kubernetes.io/docs/concepts/services-networking/add-entries-to-pod-etc-hosts-with-host-aliases/).
+This can be particularly useful for providing hostname addresses
+for services not managed by Kubernetes, like HDFS.
+
+{% navtabs hostAliases %}
+{% navtab helm %}
+
+You may specify a top-level Helm value `hostAliases` which will
+apply to the Master and Worker pods in the chart.
+```properties
+hostAliases:
+- ip: "127.0.0.1"
+  hostnames:
+    - "foo.local"
+    - "bar.local"
+- ip: "10.1.2.3"
+  hostnames:
+    - "foo.remote"
+    - "bar.remote"
+```
+
+{% endnavtab %}
+{% navtab kubectl %}
+
+You may add the `hostAliases` field to any of the Alluxio Pod template
+specs. For example:
+```properties
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: alluxio-master
+spec:
+  template:
+    spec:
+      hostAliases:
+      - ip: "127.0.0.1"
+        hostnames:
+          - "foo.local"
+          - "bar.local"
+      - ip: "10.1.2.3"
+        hostnames:
+          - "foo.remote"
+          - "bar.local"
+```
+
+{% endnavtab %}
+{% endnavtabs %}
+
+#### Deployment Strategy
+
+[By default](https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#strategy)
+Kubernetes will use the 'RollingUpdate' deployment strategy to progressively
+upgrade Pods when changes are detected.
+
+{% navtabs deployStrategy %}
+{% navtab helm %}
+
+The Helm chart currently only supports `strategy` for the logging server deployment:
+```properties
+logserver:
+  strategy:
+    type: RollingUpdate
+    rollingUpdate:
+      maxUnavailable: 25%
+      maxSurge: 1
+```
+
+{% endnavtab %}
+{% navtab kubectl %}
+
+You may add a `strategy` field to any of the Alluxio Pod template
+specs to have the Pod run using the matching ServiceAccount. For example:
+```properties
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: alluxio-master
+spec:
+  template:
+    spec:
+      strategy:
+        type: Recreate
+```
+
+{% endnavtab %}
+{% endnavtabs %}
+
 ## Troubleshooting
 
 {% accordion worker_host %}