fix(k8s): harden securityContext on static manifests (KSV-0014/KSV-0118)

[PenguinzTech]

Sets readOnlyRootFilesystem: true, drops ALL capabilities, adds seccompProfile RuntimeDefault (pod + container level) + writable /tmp emptyDir on flask-backend, go-backend, webui deployments in both kustomize/base and k8s/manifests. Helm charts were already compliant. Closes trivy KSV-0014 + KSV-0118 HIGH findings.

🤖 Generated with Claude Code

Summary by Sourcery

Harden Kubernetes security settings for backend and web UI deployments in static manifests to align with recommended defaults and resolve security findings.

Enhancements:

• Configure pod-level securityContext for flask-backend, go-backend, and webui deployments to run as non-root with a dedicated user and RuntimeDefault seccomp profile.
• Tighten container-level securityContext by enabling read-only root filesystems, dropping all Linux capabilities, and applying RuntimeDefault seccomp profiles.
• Add writable /tmp emptyDir volumes and mounts to deployments that require temporary filesystem access in both kustomize base and raw k8s manifests.

[sourcery-ai]

Reviewer's Guide

This PR hardens the Kubernetes security context for the flask-backend, go-backend, and webui deployments in both kustomize/base and k8s/manifests by enforcing non-root execution, RuntimeDefault seccomp, read-only root filesystems, dropping all capabilities, and providing a writable /tmp via emptyDir.

File-Level Changes

Change	Details	Files
Harden pod-level security context for all backend and webui deployments.	Add pod-level securityContext with runAsNonRoot: true and runAsUser: 1000 Configure pod-level seccompProfile type: RuntimeDefault	k8s/kustomize/base/flask-backend/deployment.yaml k8s/kustomize/base/go-backend/deployment.yaml k8s/kustomize/base/webui/deployment.yaml k8s/manifests/flask-backend/deployment.yaml k8s/manifests/go-backend/deployment.yaml k8s/manifests/webui/deployment.yaml
Strengthen container-level security settings to comply with Trivy KSV-0014 and KSV-0118.	Set readOnlyRootFilesystem: true on containers Ensure allowPrivilegeEscalation: false is retained Drop all Linux capabilities via capabilities: drop: [ALL] Configure container-level seccompProfile type: RuntimeDefault	k8s/kustomize/base/flask-backend/deployment.yaml k8s/kustomize/base/go-backend/deployment.yaml k8s/kustomize/base/webui/deployment.yaml k8s/manifests/flask-backend/deployment.yaml k8s/manifests/go-backend/deployment.yaml k8s/manifests/webui/deployment.yaml
Provide writable /tmp storage for applications while keeping root filesystem read-only.	Add /tmp volumeMount on containers using a named tmp volume Define a pod-level tmp volume backed by emptyDir: {}	k8s/kustomize/base/flask-backend/deployment.yaml k8s/kustomize/base/go-backend/deployment.yaml k8s/kustomize/base/webui/deployment.yaml k8s/manifests/flask-backend/deployment.yaml k8s/manifests/go-backend/deployment.yaml k8s/manifests/webui/deployment.yaml

---

Tips and commands

Interacting with Sourcery

• Trigger a new review: Comment @sourcery-ai review on the pull request.
• Continue discussions: Reply directly to Sourcery's review comments.
• Generate a GitHub issue from a review comment: Ask Sourcery to create an
  issue from a review comment by replying to it. You can also reply to a
  review comment with @sourcery-ai issue to create an issue from it.
• Generate a pull request title: Write @sourcery-ai anywhere in the pull
  request title to generate a title at any time. You can also comment
  @sourcery-ai title on the pull request to (re-)generate the title at any time.
• Generate a pull request summary: Write @sourcery-ai summary anywhere in
  the pull request body to generate a PR summary at any time exactly where you
  want it. You can also comment @sourcery-ai summary on the pull request to
  (re-)generate the summary at any time.
• Generate reviewer's guide: Comment @sourcery-ai guide on the pull
  request to (re-)generate the reviewer's guide at any time.
• Resolve all Sourcery comments: Comment @sourcery-ai resolve on the
  pull request to resolve all Sourcery comments. Useful if you've already
  addressed all the comments and don't want to see them anymore.
• Dismiss all Sourcery reviews: Comment @sourcery-ai dismiss on the pull
  request to dismiss all existing Sourcery reviews. Especially useful if you
  want to start fresh with a new review - don't forget to comment
  @sourcery-ai review to trigger a new review!

Customizing Your Experience

Access your dashboard to:

• Enable or disable review features such as the Sourcery-generated pull request
  summary, the reviewer's guide, and others.
• Change the review language.
• Add, remove or edit custom review instructions.
• Adjust other review settings.

Getting Help

• Contact our support team for questions or feedback.
• Visit our documentation for detailed guides and information.
• Keep in touch with the Sourcery team by following us on X/Twitter, LinkedIn or GitHub.

[sourcery-ai]

Hey - I've found 1 issue

Prompt for AI Agents

Please address the comments from this code review:

## Individual Comments

### Comment 1
<location path="k8s/kustomize/base/flask-backend/deployment.yaml" line_range="141-148" />
<code_context>
           runAsUser: 1000
           allowPrivilegeEscalation: false
-          readOnlyRootFilesystem: false
+          readOnlyRootFilesystem: true
+          capabilities:
+            drop: [ALL]
+          seccompProfile:
+            type: RuntimeDefault
+        volumeMounts:
+        - name: tmp
+          mountPath: /tmp
+      volumes:
+      - name: tmp
</code_context>
<issue_to_address>
**question (bug_risk):** Double-check all write paths given the new readOnlyRootFilesystem + single /tmp mount setup.

With `readOnlyRootFilesystem: true`, only mounted volumes are writable, and this pod currently exposes just `/tmp` via `emptyDir`. If the Flask app or any sidecar writes to other locations (e.g. `/var/tmp`, home directories, or root‑FS log paths), this will now fail at runtime. Please verify that all expected write locations are covered, or add additional writable mounts as needed.
</issue_to_address>

---

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

• X
• Mastodon
• LinkedIn
• Facebook

_{Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.}

[sourcery-ai]

question (bug_risk): Double-check all write paths given the new readOnlyRootFilesystem + single /tmp mount setup.

With readOnlyRootFilesystem: true, only mounted volumes are writable, and this pod currently exposes just /tmp via emptyDir. If the Flask app or any sidecar writes to other locations (e.g. /var/tmp, home directories, or root‑FS log paths), this will now fail at runtime. Please verify that all expected write locations are covered, or add additional writable mounts as needed.