* fix(example): keep agents usable when DSH's inner sandbox has no backend DSH confines bash commands itself (bubblewrap, else Landlock) and fails closed with SANDBOX_UNAVAILABLE when no runner is usable. In this hardened pod - non-root, capabilities dropped, seccomp RuntimeDefault - bubblewrap cannot start (it needs CAP_SYS_ADMIN) and the pod exposes no Landlock runner, so the shipped workspace-write default made every command fail: sandbox mode "workspace-write" is requested but no sandbox backend is usable The DSH base bundle at the pinned ref documents DSH_PERMISSION_MODE as the explicit deployment override, so set it to danger-full-access in both sandbox templates. The per-user pod is the isolation boundary in this example (its own pod, PVC and Service; non-root; all capabilities dropped), so a working agent is worth more than an inner file policy that cannot be enforced. Note that danger-full-access also turns approval prompts off. Trade-off documented rather than hidden: an agent command can now read its own DSH_HOME (including .credentials.yaml) and write anywhere in the container. Hosts where a runner works should keep workspace-write or read-only. - main-image docs: DSH_PERMISSION_MODE row plus a note on the runners and the fail-closed behavior - example README: limits bullet and a troubleshooting row with the in-pod backend check and how to restore a confined mode - architecture: tenant-isolation bullet extended - skill runbook/troubleshooting: operation guidance; never grant CAP_SYS_ADMIN or seccompProfile: Unconfined to "fix" this without an explicit decision Verified: make check (14 manifests), make lint, YAML assertions on both templates, and the override expression at the pinned dsh-v0.2.1-rc.5 base bundle (mode: !!js process.env.DSH_PERMISSION_MODE ?? 'workspace-write'). * fix(image): install bubblewrap for DSH's command sandbox DSH's Linux sandbox runner chain is bubblewrap, then Landlock, and it fails closed with SANDBOX_UNAVAILABLE when neither works. The image shipped neither, so a sandboxed agent had no way to execute confined commands. Add bubblewrap to the runtime stage. Debian ships it unsetuid (0.12.0), so it still needs unprivileged user namespaces plus the namespace/mount syscalls: in a hardened pod (all capabilities dropped, RuntimeDefault seccomp) it usually cannot create one, and DSH then falls back to Landlock or, failing that, to the DSH_PERMISSION_MODE=danger-full-access override the templates already set. Where the host allows an unprivileged user namespace, the first-choice runner now exists, so the confined modes can be restored. Docs corrected to match: bubblewrap is no longer "absent"; the blocker is the unsetuid binary's namespace requirement, not a missing CAP_SYS_ADMIN grant. Verified: make check, make lint; the package exists in the pinned base (node:24-trixie-slim, bubblewrap 0.12.0-1~deb13u1); a throwaway container with the pod's flags (--user 1000 --cap-drop ALL --security-opt no-new-privileges) still cannot create a namespace, which is why the override stays. No local image build was run. * ci(image): build and smoke-test the main image on PRs that touch it The Dockerfile and the pins in versions.env could only be validated by a merge to main or by running `make image` by hand; neither gives a PR-time signal. Add ci-image.yaml: on pull requests that change Dockerfile, .dockerignore or versions.env (and on manual dispatch) it builds linux/amd64 natively with the pins sourced from versions.env - no registry login, no push - loads the image locally and smoke-tests it: - the packaged CLI runs and reports the pinned version - the container is the non-root node user (1000) and owns /workspace + DSH_HOME - the bubblewrap command-sandbox runner is present - the OCI version label matches versions.env - a container serves /favicon.svg (the same unauthenticated probe the shipped manifests use), with logs filtered so the launch token is never printed Path-filtered like the other on-demand checks, so it is not a required status check; the published multi-arch build stays in build-main.yaml and release.yaml. Docs updated in the same change: AGENTS.md repository map and testing table, docs/gitflow.md checks section, docs/main-image.md build section. Verified: actionlint 1.7.12 and yamllint 1.38.0 (CI versions) clean over the whole repository, plus make check and make lint. --------- Co-authored-by: SREDevOpsAgents <agents@sredevops.org>
Minimal single-tenant DSH Web
The smallest Kubernetes deployment of DeepSeek Harness (DSH) Web: one
SandboxTemplate, a one-replica warm pool and one claim. It is the "just one
DSH Web instance" quickstart.
For the full platform — warm pool sizing, per-user claims, a browser-facing
gateway with cookie sessions, idle-suspend and wake-on-connect — see
examples/dsh-agents-as-a-service/.
This example deliberately has no gateway: you reach DSH through a
kubectl port-forward and its launch-token URL.
Prerequisites
-
A Kubernetes cluster with a default StorageClass (kind and GKE both work).
-
The agent-sandbox controller with extensions (API
v1beta1) installed. The version is pinned asAGENT_SANDBOX_VERSIONinversions.env:# from the repository root: . versions.env kubectl apply -f "https://github.com/kubernetes-sigs/agent-sandbox/releases/download/${AGENT_SANDBOX_VERSION}/sandbox-with-extensions.yaml" kubectl -n agent-sandbox-system rollout status deployment --timeout=180s -
A DeepSeek API key for real model calls. The pod starts without one; only model requests fail. Optionally create
dsh-provider-keys-extrafor OpenRouter, Gemini, NVIDIA or other provider keys (the template references it withoptional: true).
Quickstart
Run these from this example's directory (examples/minimal-single-tenant/).
# 1. Namespace + shared provider keys. They are injected into the sandbox via
# envFrom and are never committed.
kubectl create namespace dsh-demo
kubectl -n dsh-demo create secret generic dsh-provider-keys \
--from-literal=DEEPSEEK_API_KEY="sk-..."
# Optional: extra providers, injected through a second Secret. Create it before
# the warm pool so the pods are stamped with the keys.
kubectl -n dsh-demo create secret generic dsh-provider-keys-extra \
--from-literal=OPENROUTER_API_KEY="sk-or-..." \
--from-literal=GEMINI_API_KEY="..." \
--from-literal=NVIDIA_API_KEY="nvapi-..."
# 2. The template itself (image pinned in the manifest).
kubectl apply -f manifests/sandbox-template.yaml
# 3. A template only describes pods; a warm pool turns it into running
# Sandboxes and a claim adopts one. One replica is enough here.
kubectl apply -f - <<'EOF'
apiVersion: extensions.agents.x-k8s.io/v1beta1
kind: SandboxWarmPool
metadata:
name: dsh-pool
namespace: dsh-demo
spec:
replicas: 1
sandboxTemplateRef:
name: dsh-web-template
---
apiVersion: extensions.agents.x-k8s.io/v1beta1
kind: SandboxClaim
metadata:
name: dsh
namespace: dsh-demo
spec:
warmPoolRef:
name: dsh-pool
EOF
kubectl -n dsh-demo wait sandboxclaim/dsh --for=condition=Ready --timeout=180s
Talk to the instance
DSH gates / behind a launch token it prints only in its startup logs. Open
the printed URL once; DSH then sets its own auth cookie and the UI loads
normally.
SB=$(kubectl -n dsh-demo get sandboxclaim dsh -o jsonpath='{.status.sandbox.name}')
kubectl -n dsh-demo logs "$SB" | grep -m1 '?token='
# dsh web: http://<pod-ip>:3080/?token=...
kubectl -n dsh-demo port-forward "pod/$SB" 18081:3080
# open http://localhost:18081/?token=... from the log line
Port note: DSH Web listens on
3080in-cluster. If3080is already in use on your workstation, forward to another local port (here18081), never3080.localhostis always in DSH's trusted-host list, so the forwarded request is accepted.gVisor caveat: if you uncomment
runtimeClassName: gvisorin the template,kubectl port-forwardno longer works. Use the multi-tenant gateway example or a reachable Service instead; see optional hardening.
Network policy and optional hardening
The template omits networkPolicyManagement, so the agent-sandbox controller
uses its Managed secure default: ingress only from the sandbox-router, public
egress, and no internal cluster DNS. kubectl port-forward is local to the pod
and still works (except under gVisor).
gVisor, an optional nodeSelector, extra provider keys and a stricter sandbox
NetworkPolicy are documented in
optional hardening.
Probes and trusted hosts
Two settings in manifests/sandbox-template.yaml are easy to get wrong:
- Probe path.
/returns401without the launch-token cookie, so a probe there crash-loops the pod. The template probes/favicon.svg(served unauthenticated) and gates liveness/readiness behind astartupProbe, which gives a cold start (plugin activation, or the first resume) up to 120s before a restart. - Host allow-list. DSH rejects unknown
Hostheaders.localhostand127.0.0.1are always trusted; if you later front the sandbox with an Ingress or proxy, setDSH_TRUSTED_HOSTSto that public host (comma or space separated). The full example explains both exposure variants inmanifests/exposure/README.md.
The template also sets fsGroupChangePolicy: OnRootMismatch. DSH's
credentials plugin requires .credentials.yaml to be 0600, while the
kubelet's default fsGroup policy rewrites it to 0660 on every pod start —
without this policy a recreated or resumed sandbox crash-loops. The rationale
is spelled out in
10-sandboxtemplate.yaml.
Suspend, resume and clean up
# Suspend: the pod is deleted, the PVC (state) and Service are kept.
kubectl -n dsh-demo patch sandbox "$SB" --type merge -p '{"spec":{"operatingMode":"Suspended"}}'
# Resume: a new pod reattaches the same PVC; conversations survive.
kubectl -n dsh-demo patch sandbox "$SB" --type merge -p '{"spec":{"operatingMode":"Running"}}'
kubectl -n dsh-demo wait sandbox "$SB" --for=condition=Ready --timeout=180s
# Delete everything this quickstart created.
kubectl -n dsh-demo delete sandboxclaim dsh
kubectl delete namespace dsh-demo
Deleting the claim cascades to the sandbox and its PVC.