K8E — Tandem storage, MCP gateway, and persistent warm-pool workspaces

A roundup of what shipped in the k8e repository since the announcement post — every item below is a real commit on main, grouped by theme.

Tandem: rqlite-backed etcd compatibility (KIP-29)

Embedded etcd is replaced by Tandem, a rqlite-backed etcd v3 compatibility layer, as the sole datastore backend.

M0/M1 compatibility layer — the etcd v3 API surface implemented over rqlite, with a differential test suite that runs the same workload against real embedded etcd and asserts identical results (7318d448, 0ef61485, 5dc477f0, d46f2b9c)
Differential testing — crash recovery, lease expiry, watch slow-consumer, and compaction concurrent-reader differentials all pass; each divergence the suite found was fixed in the layer (bed6c1ea, b3e7b66a, a80c8cd5, 14b9a6b3, 3fd5b683)
Multi-member clusters — members can join and leave a running group, Raft traffic between members is protected with mTLS, and a member that leaves is removed and stopped (40485f28, 896e6f75, 5972090a)
Snapshot/Restore — /db/snapshot HTTP handler and Snapshot/Restore RPCs implemented (0aac4bc3)
Packaging — rqlite is wired into the packaging and download chain, and the Tandem datastore endpoint defaults to https (7374b4fc, a9482738)
Single-node M1 validated — all single-node differential axes complete; network-partition, lease clock-skew, and compaction-reclamation validated on a three-node cluster (c39dd382, d3212bab, 6c0501a1, a4e8e81b)

Unified session model — warm pool carries workspace PVCs. Every sandbox session is now persistent; the ephemeral/persistent split is gone. Each warm pod boots with its own pre-provisioned workspace claim (1Gi local-path), so claiming a warm pod yields a persistent VM — fast start and a PVC workspace (647ac2e0)
MCP through the K8E API Gateway — the sandbox MCP service follows the 2026-07-28 HTTP protocol boundary, is exposed through the gateway, and ships a deployable k8e-mcp image in the release (665103ee, dcd9f91e, 30a1ff18)
Configurable sandbox namespace end to end — --sandbox-namespace / K8E_SANDBOX_NAMESPACE now flows through every component that touches sandbox Pods, Secrets and Services (af19fa17)
Background runs past 30s — run --background jobs stay alive past the 30s exec window and are reaped on session reset (211c57e1)
API Key MCP entry operable, with readiness tests and static-analysis gates cleared (1a12f32e, 03094216)

Kubernetes v1.37.0-k3s1 + etcd v3.7.1-k3s1 — the full dependency upgrade, including the kubelet v1.37 adaptation (the --containerd flag is gone) (3b005782, 2ab761d8)
Bundled cert-manager v1.21.2 — bundled by default with a documented lifecycle and opt-out (4d9f2ad3, 79d55e15)
Legacy cloud controllers dropped from kube-controller-manager (c7120e36)
Installer fixes — official gVisor tarball release for the runtime install (matching the 2026-07 multi-file layout), invalid --bootstrap flag removed from auto-configure, and the release publishes sha256sum-amd64.txt so the install.sh checksum path works (7711faef, 8f819146, 262e39ab)

arm64 k8e binary built and published in the release pipeline (f62c5b8f)
E2E l1/l2 profiles run in CI with a docker-based harness; L1 30/30 and L2 24/24 pass on OrbStack arm64 (d807a031, 58641be7)
sandbox-mcp manifests default-skipped so unrunnable pods stop shipping when the component is disabled (817e98dd)
Static-analysis gates (SonarCloud + DeepSource) unblocked on new code

README slimmed and re-focused: the logo is now https://k8e.sh/images/k8e-mark-on-dark.svg, gVisor install steps match the official tarball layout, the capabilities table reflects the persistent-workspace model, and tutorial content moved to k8e.sh/docs

curl -sfL https://k8e.sh/install.sh | sh -

Then connect your AI agent (Claude Code, Codex, or Pi) with the standalone k8e-sandbox-cli. See the Getting Started guide.