K8s: Distributor uses Greedy algo as slot selector strategy in autoscaling

[VietND96]

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Description

Add the implementation in Grid core to Docker and Helm chart - SeleniumHQ/selenium#15897 ([grid] Add GreedySlotSelector as a built-in slot-selector option)

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

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PR Type

Enhancement

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Description

• Add slot selector strategy configuration for Selenium Grid

• Enable GreedySlotSelector as default for autoscaling scenarios

• Support slot selector in Hub, Distributor, and Standalone modes

• Update Helm chart with new configuration options

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Changes diagram

flowchart LR
  A["Shell Scripts"] --> B["SE_DISTRIBUTOR_SLOT_SELECTOR"]
  C["Helm Templates"] --> D["slotSelectorStrategy Config"]
  D --> E["Hub Deployment"]
  D --> F["Distributor Deployment"]
  G["values.yaml"] --> H["GreedySlotSelector Default"]
  H --> I["Autoscaling Optimization"]

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Changes walkthrough 📝

	Relevant files
Enhancement	6 files start-selenium-grid-distributor.sh Add slot selector environment variable support                      +4/-0      start-selenium-grid-hub.sh Add slot selector environment variable support                      +4/-0      start-selenium-grid-standalone.sh Add slot selector environment variable support                      _helpers.tpl Add slot selector strategy helper template                              +10/-0    distributor-deployment.yaml Configure slot selector environment variable                          +4/-0      hub-deployment.yaml Configure slot selector environment variable                          +4/-0
Documentation	1 files CONFIGURATION.md Document new slot selector configuration options                  +3/-0
Configuration changes	1 files values.yaml Add slot selector configuration with defaults                        +10/-0
Additional files	1 files start-selenium-standalone.sh +4/-0

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PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Logic Complexity The template logic for determining slot selector strategy has complex conditional branching between KEDA and non-KEDA modes. The ternary operator usage should be validated to ensure correct behavior in all scenarios. {{- define "seleniumGrid.autoscaling.distributor.slotSelector" -}} {{- $slotSelector := "" -}} {{- if eq (include "seleniumGrid.useKEDA" $) "true" -}} {{- $slotSelector = $.Values.autoscaling.slotSelectorStrategy -}} {{- else -}} {{- $slotSelector = $.Values.isolateComponents | ternary $.Values.components.distributor.slotSelectorStrategy $.Values.hub.slotSelectorStrategy -}} {{- end -}} {{- $slotSelector -}} {{- end -}} Default Value The default slot selector strategy is set to GreedySlotSelector which changes existing behavior. This breaking change should be carefully validated for backward compatibility impact. slotSelectorStrategy: "org.openqa.selenium.grid.distributor.selector.GreedySlotSelector" # -- Specify an external KEDA TriggerAuthentication resource is used for scaler triggers config. Apply for all browser nodes

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PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Add safe default for undefined variable The template logic assumes $.Values.isolateComponents exists but this variable is not defined in the values.yaml. This could cause template rendering failures when components are not isolated. Add a default value or safe check for this variable. charts/selenium-grid/templates/_helpers.tpl [205-213] {{- define "seleniumGrid.autoscaling.distributor.slotSelector" -}} {{- $slotSelector := "" -}} {{- if eq (include "seleniumGrid.useKEDA" $) "true" -}} {{- $slotSelector = $.Values.autoscaling.slotSelectorStrategy -}} {{- else -}} -{{- $slotSelector = $.Values.isolateComponents | ternary $.Values.components.distributor.slotSelectorStrategy $.Values.hub.slotSelectorStrategy -}} +{{- $slotSelector = (default false $.Values.isolateComponents) | ternary $.Values.components.distributor.slotSelectorStrategy $.Values.hub.slotSelectorStrategy -}} {{- end -}} {{- $slotSelector -}} {{- end -}} Apply / Chat Suggestion importance[1-10]: 7 __ Why: The suggestion correctly identifies that using $.Values.isolateComponents without a default value can make the Helm template rendering fail if the value is not defined, and the proposed fix using default is a robust improvement.	Medium
Update

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CI Feedback 🧐

(Feedback updated until commit c146faf)

A test triggered by this PR failed. Here is an AI-generated analysis of the failure:

Action: Rerun workflow when failure

Failed stage: Authenticate GitHub CLI for PR [❌]

Failure summary: The action failed during GitHub CLI authentication. The token provided via GH_CLI_TOKEN_PR is missing the required 'read:org' scope, which is necessary for the GitHub CLI to function properly.

Relevant error logs: 1: ##[group]Runner Image Provisioner 2: Hosted Compute Agent ... 24: Issues: write 25: Metadata: read 26: Models: read 27: Packages: write 28: Pages: write 29: PullRequests: write 30: RepositoryProjects: write 31: SecurityEvents: write 32: Statuses: write 33: ##[endgroup] 34: Secret source: Actions 35: Prepare workflow directory 36: Prepare all required actions 37: Getting action download info 38: Download action repository 'actions/checkout@main' (SHA:09d2acae674a48949e3602304ab46fd20ae0c42f) 39: Complete job name: Rerun workflow when failure 40: ##[group]Run actions/checkout@main ... 44: ssh-strict: true 45: ssh-user: git 46: persist-credentials: true 47: clean: true 48: sparse-checkout-cone-mode: true 49: fetch-depth: 1 50: fetch-tags: false 51: show-progress: true 52: lfs: false 53: submodules: false 54: set-safe-directory: true 55: env: 56: GH_CLI_TOKEN: *** 57: GH_CLI_TOKEN_PR: *** 58: RUN_ID: 16036992847 59: RERUN_FAILED_ONLY: true 60: RUN_ATTEMPT: 1 ... 115: Or undo this operation with: 116: git switch - 117: Turn off this advice by setting config variable advice.detachedHead to false 118: HEAD is now at 3661f33 Merge c146faf79bf52ccb3868d2e3f20b7f91000373c5 into 2641d8d9f59a90ce1a6230cb69bf433a9949b706 119: ##[endgroup] 120: [command]/usr/bin/git log -1 --format=%H 121: 3661f3354ed3afbaeb3b9f404152a8457703cbf9 122: ##[group]Run sudo apt update 123: �[36;1msudo apt update�[0m 124: �[36;1msudo apt install gh�[0m 125: shell: /usr/bin/bash -e {0} 126: env: 127: GH_CLI_TOKEN: *** 128: GH_CLI_TOKEN_PR: *** 129: RUN_ID: 16036992847 130: RERUN_FAILED_ONLY: true 131: RUN_ATTEMPT: 1 ... 176: Reading state information... 177: 46 packages can be upgraded. Run 'apt list --upgradable' to see them. 178: WARNING: apt does not have a stable CLI interface. Use with caution in scripts. 179: Reading package lists... 180: Building dependency tree... 181: Reading state information... 182: gh is already the newest version (2.74.2). 183: 0 upgraded, 0 newly installed, 0 to remove and 46 not upgraded. 184: ##[group]Run echo "$GH_CLI_TOKEN_PR" | gh auth login --with-token 185: �[36;1mecho "$GH_CLI_TOKEN_PR" | gh auth login --with-token�[0m 186: shell: /usr/bin/bash -e {0} 187: env: 188: GH_CLI_TOKEN: *** 189: GH_CLI_TOKEN_PR: *** 190: RUN_ID: 16036992847 191: RERUN_FAILED_ONLY: true 192: RUN_ATTEMPT: 1 193: ##[endgroup] 194: error validating token: missing required scope 'read:org' 195: ##[error]Process completed with exit code 1. 196: Post job cleanup.