8000 feat(helm): add Helm chart for Kubernetes deployment by ayushgharat234 · Pull Request #4399 · googleapis/mcp-toolbox · GitHub
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feat(helm): add Helm chart for Kubernetes deployment - #4399

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ayushgharat234:feat/helm-chart
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feat(helm): add Helm chart for Kubernetes deployment#4399
ayushgharat234 wants to merge 2 commits into
googleapis:mainfrom
ayushgharat234:feat/helm-chart

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@ayushgharat234 ayushgharat234 commented Nov 2, 2026 •
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Description

Adds a Helm chart at charts/mcp-toolbox for deploying Toolbox to Kubernetes, with helm-unittest tests. This is the first of the three PRs proposed in #486. A kind-based CI job and docs will follow in separate PRs.

The tool configuration comes from a chart-managed Secret (config.toolsYaml), an existing Secret (config.existingSecret) or prebuilt tool sets (config.prebuilt). The default settings pass the restricted Pod Security Standard. Ingress, HPA and PDB are optional. The chart README covers usage.

Design decisions

Choice Reason
--poll-interval=10 by default (config.pollInterval) Kubernetes updates mounted Secrets by swapping a ..data symlink. The fsnotify watcher in cmd/root.go doesn't detect that swap, so without polling an updated Secret is never reloaded. The Secret is also mounted as a directory, because subPath mounts never receive updates.
runAsUser: 65532 set explicitly The image runs as the named user nonroot. With only runAsNonRoot: true, the kubelet can't verify that user and the pod fails with CreateContainerConfigError.
.gitignore: mcp-toolbox → /mcp-toolbox The unanchored binary pattern also ignored charts/mcp-toolbox/.

Testing

helm lint --strict and helm unittest (27 tests) pass. I also installed the chart on Kubernetes v1.36.1 in a namespace that enforces the restricted Pod Security Standard. The MCP endpoint responded, an updated Secret was reloaded in 58s with no restart, and allowedHosts returned 403 for an unlisted host while /healthz stayed reachable.

Verification output 
=== Effective security context ===
{"fsGroup":65532,"runAsGroup":65532,"runAsNonRoot":true,"runAsUser":65532,"seccompProfile":{"type":"RuntimeDefault"}}
{"allowPrivilegeEscalation":false,"capabilities":{"drop":["ALL"]},"readOnlyRootFilesystem":true}

=== Container args ===
["--address=0.0.0.0","--port=5000","--config=/etc/toolbox/tools.yaml","--poll-interval=10"]

=== GET /healthz ===
HTTP 200

=== MCP initialize ===
{"jsonrpc":"2.0","id":1,"result":{"protocolVersion":"2025-06-18",...,"serverInfo":{"name":"Toolbox","version":"1.15.0+container.release.linux.amd64.8e8e569"}}}

=== MCP tools/list (v1 config) ===
"name":"list-tables"

=== Hot reload: update the Secret to v2 (adds sqlite-version) ===
reloaded after 58s
"name":"list-tables"
"name":"sqlite-version"
NAME                                   RESTARTS
toolbox-mcp-toolbox-6f6448468c-sxf4v   0

=== allowedHosts: restrict to toolbox.example.com ===
/healthz, any Host:             HTTP 200
/mcp, Host evil.example.com:    HTTP 403
/mcp, Host toolbox.example.com: HTTP 200

PR Checklist

  • Make sure you reviewed CONTRIBUTING.md
  • Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
  • Ensure you have manually reviewed the entire diff before requesting a review
  • Ensure the tests and linter pass
  • Code coverage does not decrease (if any source code was changed)
  • Appropriate docs were updated (if necessary)
  • Make sure to add ! if this involve a breaking change

Fixes #486

@ayushgharat234
feat(helm): add Helm chart for Kubernetes deployment
be3d7f8 
Adds charts/mcp-toolbox with a chart-managed or existing Secret for tools.yaml, prebuilt tool sets, restricted Pod Security Standard defaults, optional Ingress, HPA and PodDisruptionBudget, and helm-unittest tests.

Anchors the mcp-toolbox binary pattern in .gitignore so it no longer ignores the chart directory.
@ayushgharat234
ayushgharat234 requested a review from a team as a code owner November 2, 2026 17:39
@ayushgharat234 ayushgharat234 mentioned this pull request Nov 2, 2026
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Code Review

This pull request introduces a new Helm chart for deploying the MCP Toolbox for Databases to Kubernetes, including templates for deployment, service, ingress, autoscaling, and security configurations, along with comprehensive unit tests. The review feedback suggests quoting ingress path values to prevent parsing errors, extending the security warning in the release notes to cover ingress-exposed ClusterIP services, and adding support for mounting custom volumes and volume mounts to facilitate database certificate and credential injection.

Comment thread charts/mcp-toolbox/templates/ingress.yaml Resolved
Comment thread charts/mcp-toolbox/templates/NOTES.txt Resolved
Comment thread charts/mcp-toolbox/templates/deployment.yaml Resolved
Comment thread charts/mcp-toolbox/templates/deployment.yaml Resolved
Comment thread charts/mcp-toolbox/values.yaml Resolved

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Add Helm chart for Kubernetes deployment

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