OLS-3435: add writable home volume for agent container

[tremes]

The Claude Code Bash tool requires a writable ~/.claude directory on startup. With readOnlyRootFilesystem: true and no writable volume at /home/agent, executions fail with EACCES when the tool tries to mkdir /home/agent/.claude.

Add an emptyDir volume "home" mounted at /home/agent in the bootstrap SandboxTemplate, bare-pod PodSpecBuilder, and e2e test sandbox template.

Assisted-by: Claude Code:claude-opus-4-6

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⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: dd010832-4159-43a2-8849-f4917fc46ed6

📥 Commits

Reviewing files that changed from the base of the PR and between 058e0bf and 0958f7c.

📒 Files selected for processing (5)

• controller/proposal/podspec_builder.go
• controller/proposal/podspec_builder_test.go
• controller/sandbox/bootstrap.go
• controller/sandbox/bootstrap_test.go
• test/agent/sandboxtemplate/sandboxtemplate.yaml

📝 Walkthrough

Walkthrough

This PR adds a new "home" emptyDir volume mounted at /home/agent for agent containers, applied in the PodSpecBuilder, the sandbox bootstrap template generation, and the corresponding test manifest, replacing prior skills-volume-only configuration in bootstrap.go.

Changes

Home volume mount addition

Layer / File(s)	Summary
PodSpecBuilder home volume controller/proposal/podspec_builder.go	Appends a home emptyDir volume and mounts it at /home/agent in the main container.
Sandbox bootstrap template home volume controller/sandbox/bootstrap.go	Adds a volumeMounts entry for home at /home/agent in the agent container and defines home as emptyDir, replacing the prior skills volume config with an image reference.
Test manifest update test/agent/sandboxtemplate/sandboxtemplate.yaml	Updates the manifest to mount home at /home/agent and define it as emptyDir, keeping the existing skills volume.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description accurately describes the writable /home/agent volume change across the three affected templates.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title accurately summarizes the main change: adding a writable home volume for the agent container.

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[coderabbitai]

🧹 Nitpick comments (2)

controller/proposal/podspec_builder.go (2)

64-67: 🚀 Performance & Scalability | 🔵 Trivial | ⚡ Quick win

Consider a SizeLimit on the new emptyDir.

The home emptyDir has no size bound, so unbounded writes under .claude (cache, session artifacts) could consume node disk. Not critical since it's ephemeral per-pod, but worth capping given this runs untrusted agent workloads.

♻️ Proposed fix

 	volumes = append(volumes, corev1.Volume{
 		Name:         "home",
-		VolumeSource: corev1.VolumeSource{EmptyDir: &corev1.EmptyDirVolumeSource{}},
+		VolumeSource: corev1.VolumeSource{EmptyDir: &corev1.EmptyDirVolumeSource{
+			SizeLimit: resource.NewQuantity(256*1024*1024, resource.BinarySI),
+		}},
 	})

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@controller/proposal/podspec_builder.go` around lines 64 - 67, The new home
emptyDir in podspec_builder.go is currently unbounded and can grow with writes
under .claude. Update the Volume creation in the pod spec builder to set a
SizeLimit on the corev1.EmptyDirVolumeSource for the "home" volume, using a
reasonable cap for this workload. Keep the change localized to the volume setup
in the podspec builder so the home mount remains ephemeral but constrained.

---

54-72: 🔒 Security & Privacy | 🔵 Trivial | ⚡ Quick win

Set ReadOnlyRootFilesystem: true if the pod is meant to be read-only. controller/proposal/podspec_builder.go still leaves the container root filesystem writable; the new /home/agent emptyDir only fixes that mount point. If the hardening goal is a read-only rootfs, set it here (and in controller/sandbox/bootstrap.go) so the generated spec matches the stated rationale.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@controller/proposal/podspec_builder.go` around lines 54 - 72, The hardening
in podspec_builder should also enforce a read-only root filesystem, since the
new /home/agent emptyDir only covers that mount point. Update the container
SecurityContext in podspec_builder's container setup to set
ReadOnlyRootFilesystem to true, and mirror the same change in
controller/sandbox/bootstrap.go so both generated pod specs match the intended
read-only design.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@controller/proposal/podspec_builder.go`:
- Around line 64-67: The new home emptyDir in podspec_builder.go is currently
unbounded and can grow with writes under .claude. Update the Volume creation in
the pod spec builder to set a SizeLimit on the corev1.EmptyDirVolumeSource for
the "home" volume, using a reasonable cap for this workload. Keep the change
localized to the volume setup in the podspec builder so the home mount remains
ephemeral but constrained.
- Around line 54-72: The hardening in podspec_builder should also enforce a
read-only root filesystem, since the new /home/agent emptyDir only covers that
mount point. Update the container SecurityContext in podspec_builder's container
setup to set ReadOnlyRootFilesystem to true, and mirror the same change in
controller/sandbox/bootstrap.go so both generated pod specs match the intended
read-only design.

---

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Configuration used: Path: .coderabbit.yaml

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📥 Commits

Reviewing files that changed from the base of the PR and between fb09ae2 and 058e0bf.

📒 Files selected for processing (3)

• controller/proposal/podspec_builder.go
• controller/sandbox/bootstrap.go
• test/agent/sandboxtemplate/sandboxtemplate.yaml

🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

• openshift/lightspeed-agentic-sandbox (manual)

[openshift-ci-robot]

@tremes: This pull request references OLS-3435 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the bug to target the "5.0.0" version, but no target version was set.

Details

In response to this:

The Claude Code Bash tool requires a writable ~/.claude directory on startup. With readOnlyRootFilesystem: true and no writable volume at /home/agent, executions fail with EACCES when the tool tries to mkdir /home/agent/.claude.

Add an emptyDir volume "home" mounted at /home/agent in the bootstrap SandboxTemplate, bare-pod PodSpecBuilder, and e2e test sandbox template.

Assisted-by: Claude Code:claude-opus-4-6

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