Update docs for Helm config nodeDrainAfterSessionCount

Signed-off-by: Viet Nguyen Duc <[email protected]>

Author: VietND96

charts/selenium-grid/README.md

@@ -27,6 +27,7 @@ This chart enables the creation of a Selenium Grid Server in Kubernetes.
       * [Configuration `global.K8S_PUBLIC_IP`](#configuration-globalk8s_public_ip)
     * [Configuration of Nodes](#configuration-of-nodes)
       * [Container ports and Service ports](#container-ports-and-service-ports)
+      * [Settings Node drain after session count](#settings-node-drain-after-session-count)
       * [Configuration of shm size limit for browser nodes](#configuration-of-shm-size-limit-for-browser-nodes)
     * [Configuration of Probes](#configuration-of-probes)
       * [Node Probes](#node-probes)
@@ -563,6 +564,21 @@ edgeNode:
       protocol: TCP
 ```
 
+#### Settings Node drain after session count
+
+In case of autoscaling enabled, with scaling type `job`, Node will be drained following `nodeMaxSessions` (default is 1). So, behavior here is Job will take one session and then Node will be drained after that (something like one-time node). If you want to change this behavior, you can adjust the value in `nodeDrainAfterSessionCount` greater than `nodeMaxSessions` to take effect.
+
+In another hand, with scaling type `deployment`, Node only get drained when HPA choose pods to terminate (which aligns with `nodeDrainAfterSessionCount` is 0 by default). If you want to drain Node by your own logic, you can adjust the value in `nodeDrainAfterSessionCount` greater than 0 to take effect. The same logic applies in normal deployment as well (without autoscaling).
+
+```yaml
+global:
+  seleniumGrid:
+    nodeDrainAfterSessionCount: 30  # Apply for all nodes
+
+chromeNode:
+  nodeDrainAfterSessionCount: 10  # Set another value for chrome node
+```
+
 #### Configuration of shm size limit for browser nodes
 
 By default, node browsers (Chrome/Chromium, Edge) leave the config key `dshmVolumeSizeLimit` as empty. It means the `/dev/shm` volume mount is disabled, and argument `--disable-dev-shm-usage` is passed to the browser via container environment variable (get motivation from [this post](https://www.ministryoftesting.com/articles/navigating-chromedriver-crashes-in-kubernetes-a-tale-of-test-automation-resilience)). You can set another valid value to enable it back. For example:

charts/selenium-grid/templates/_helpers.tpl

@@ -572,7 +572,7 @@ template:
         - name: SE_NODE_MAX_SESSIONS
           value: {{ $nodeMaxSessions | quote }}
         - name: SE_DRAIN_AFTER_SESSION_COUNT
-          value: {{ and (eq (include "seleniumGrid.useKEDA" $) "true") (eq .Values.autoscaling.scalingType "job") | ternary $nodeMaxSessions 0 | quote }}
+          value: {{ and (eq (include "seleniumGrid.useKEDA" $) "true") (eq .Values.autoscaling.scalingType "job") | ternary (max $nodeMaxSessions $nodeDrainAfterSessionCount) $nodeDrainAfterSessionCount | quote }}
         - name: SE_NODE_PORT
           value: {{ .node.port | quote }}
         - name: DISPLAY_CONTAINER_NAME

charts/selenium-grid/values.yaml

@@ -52,8 +52,9 @@ global:
     #    Note: If not define labelSelector, it will be added automatically based on "app" label in each component
     # -- Specify number of max sessions per node. Can be overridden by individual component (this is also set to scaler trigger parameter `nodeMaxSessions` if `autoscaling` is enabled)
     nodeMaxSessions: 1
-    # Noted:In case of autoscaling enabled, with scaling type `job`, Node will be drained following `nodeMaxSessions` by default
+    # Noted: In case of autoscaling enabled, with scaling type `job`, Node will be drained following `nodeMaxSessions` by default
     # If changing `nodeDrainAfterSessionCount` > `nodeMaxSessions` it will take precedence over `nodeMaxSessions` in scaling type `job`
+    # For other cases, `nodeDrainAfterSessionCount` > 0 always take effect.
     # -- Set number of sessions will be executed in a Node before detaching it from Hub and shutting it down
     nodeDrainAfterSessionCount: 0
     # -- This causes the Node to auto manage files downloaded for a given session on the Node (https://www.selenium.dev/documentation/webdriver/drivers/remote_webdriver/#enable-downloads-in-the-grid)

tests/charts/templates/render/dummy.yaml

@@ -18,6 +18,7 @@ global:
         topologyKey: kubernetes.io/hostname
         whenUnsatisfiable: DoNotSchedule
     nodeMaxSessions: 3
+    nodeDrainAfterSessionCount: 30
     nodeEnableManagedDownloads: true
     nodeCustomCapabilities: "{'myApp:version':'beta','myApp:publish':'public'}"
 
@@ -138,6 +139,7 @@ components:
 
 chromeNode:
   nodeMaxSessions: 2
+  nodeDrainAfterSessionCount: 10
   annotations:
     "restartOnUpdate": "true"
   terminationGracePeriodSeconds: 7200
@@ -146,6 +148,7 @@ chromeNode:
 
 firefoxNode:
   nodeMaxSessions: 1
+  nodeDrainAfterSessionCount: 20
   annotations:
     "restartOnUpdate": "true"
   terminationGracePeriodSeconds: 720

tests/charts/templates/render/dummy_solution.yaml

@@ -18,6 +18,7 @@ global:
         topologyKey: kubernetes.io/hostname
         whenUnsatisfiable: DoNotSchedule
     nodeMaxSessions: 3
+    nodeDrainAfterSessionCount: 30
     nodeEnableManagedDownloads: true
     nodeCustomCapabilities: "{'myApp:version':'beta','myApp:publish':'public'}"
 
@@ -130,13 +131,15 @@ selenium-grid:
 
   chromeNode:
     nodeMaxSessions: 2
+    nodeDrainAfterSessionCount: 10
     affinity: *affinity
     terminationGracePeriodSeconds: 7200
     service:
       enabled: true
 
   firefoxNode:
     nodeMaxSessions: 1
+    nodeDrainAfterSessionCount: 20
     affinity: *affinity
     terminationGracePeriodSeconds: 720
     service: