Improve Kubernetes monitoring docs for k8s-monitoring v0.1.3 (#226)

Align with the updated chart values key and document OpenShift SCC steps for node exporter and kube-state-metrics.

Author: nastena1606

docs/monitor-kubernetes.md

@@ -28,6 +28,32 @@ To set up monitoring of Kubernetes, you need the following:
 
 ### Install the Victoria Metrics Kubernetes monitoring stack
 
+??? admonition "Install on OpenShift"
+
+    When installing the chart on OpenShift, some components might require additional Security Context Constraints (SCCs), depending on the permissions they need at runtime.
+
+    The `prometheus-node-exporter` component runs as a DaemonSet and requires access to host-level resources such as `/proc`, `/sys`, and other node-level paths. Because these are exposed through `hostPath` mounts, the service account used by `prometheus-node-exporter` must be granted an SCC that allows host access, such as `hostaccess`, `hostmount-anyuid`, or a custom SCC with equivalent permissions.
+
+    For example:
+
+    ```bash
+    oc adm policy add-scc-to-user node-exporter \
+    -z prometheus-node-exporter \
+    -n <namespace>
+    ```
+
+    Similarly, for `kube-state-metrics`, if the `restricted` SCC is enforced, avoid setting fixed user, group, or filesystem group IDs. Allow OpenShift to assign these values from the namespace UID/GID range by either adding the service account to the required SCC or by adding the following entries to the values YAML file:
+
+    ```yaml
+    kube-state-metrics:
+      securityContext:
+        runAsUser: null
+        runAsGroup: null
+        fsGroup: null
+    ```
+
+    Next, follow the steps to install Victoria Metrics Kubernetes Monitoring stack.
+
 === ":material-run-fast: Quick install"
 
     Use the [quick install script](https://raw.githubusercontent.com/Percona-Lab/k8s-monitoring/refs/tags/{{k8s_monitor_tag}}/vm-operator-k8s-stack/quick-install.sh) and the set of flags that describe your PMM Server and Kubernetes environment to install Victoria Metrics Kubernetes monitoring stack with a single command. The script installs Victoria Metrics Kubernetes monitoring stack with default parameters.
@@ -174,14 +200,14 @@ To set up monitoring of Kubernetes, you need the following:
 
     8. Install the Victoria Metrics Kubernetes monitoring stack Helm chart. You need to specify the following configuration:
 
-        * the URL to access the PMM server in the `externalVM.write.url` option in the format `<PMM-SERVER-URL>/victoriametrics/api/v1/write`. The URL can contain either the IP address or the hostname of the PMM server.
+        * the URL to access the PMM server in the `external.vm.write.url` option is in the format `<PMM-SERVER-URL>/victoriametrics/api/v1/write`. The URL can contain either the IP address or the hostname of the PMM server.
         * the unique name or an ID of the Kubernetes cluster in the `vmagent.spec.externalLabels.k8s_cluster_id` option. Ensure to set different values if you are sending metrics from multiple Kubernetes clusters to the same PMM Server. 
         * The Namespace must be the same as the Namespace for the Secret and ConfigMap
 
         ```bash
         helm install vm-k8s vm/victoria-metrics-k8s-stack \
         -f https://raw.githubusercontent.com/Percona-Lab/k8s-monitoring/refs/tags/{{k8s_monitor_tag}}/vm-operator-k8s-stack/values.yaml \
-        --set externalVM.write.url=<PMM-SERVER-URL>/victoriametrics/api/v1/write \
+        --set external.vm.write.url=<PMM-SERVER-URL>/victoriametrics/api/v1/write \
         --set vmagent.spec.externalLabels.k8s_cluster_id=<UNIQUE-CLUSTER-IDENTIFIER/NAME> \
         -n $NAMESPACE
         ```
@@ -191,7 +217,7 @@ To set up monitoring of Kubernetes, you need the following:
         ```bash
         helm install vm-k8s vm/victoria-metrics-k8s-stack \
         -f https://raw.githubusercontent.com/Percona-Lab/k8s-monitoring/refs/tags/{{k8s_monitor_tag}}/vm-operator-k8s-stack/values.yaml \
-        --set externalVM.write.url=https://pmm-example.com/victoriametrics/api/v1/write \
+        --set external.vm.write.url=https://pmm-example.com/victoriametrics/api/v1/write \
         --set vmagent.spec.externalLabels.k8s_cluster_id=test-cluster \
         -n monitoring-system
         ```

variables.yml

@@ -20,7 +20,7 @@ minikuberecommended: '1.38.1'
 binlogserverrecommended: '0.3.1'
 
 #For monitoring
-k8s_monitor_tag: 'v0.1.2'
+k8s_monitor_tag: 'v0.1.3'
 
 # Global variables