# Kata & gVisor

## Description

[Kata Containers](https://katacontainers.io/) is an OCI container runtime that starts each container inside a lightweight virtual machine with its own kernel instead of sharing the host kernel. [gVisor](https://gvisor.dev/) is a second isolating runtime, shipped as the single `runsc` binary, that intercepts container syscalls in a userspace kernel and runs without hardware virtualization.

## Overview

This role provisions the isolating runtime layer of a container host. It installs the pinned gVisor binary, then re-runs the daemon configuration of the container role so the freshly installed runtime is registered and the daemon is restarted onto it. In swarm mode it additionally labels the node as sandbox-isolating, which is the placement constraint that keeps sandboxed workloads off nodes that still default to the shared kernel.

## Cosmos

The diagram places Kata & gVisor in the Infinito.Nexus cosmos: the components it deploys (capabilities), the central services it consumes (dependencies), and its outward reach (federation and bridged external networks).

```mermaid
flowchart LR
    subgraph role [svc-virt-kata 💻]
        svc_kata["kata"]
    end
    subgraph dependents [Dependents]
        dpt_web_app_hermes["web-app-hermes 🐳🐝"]
        dpt_web_app_openclaw["web-app-openclaw 🐳🐝"]
    end
    svc_kata -- "1:1" --> dpt_web_app_hermes
    svc_kata -- "1:1" --> dpt_web_app_openclaw
```

Solid `1:1` edges are fixed relationships; dashed `0..1` edges are conditional (enabled only in matching deployments); red `0..0` edges are turned off in this role. Node markers show the role's deploy modes (💻 host, 🐳 compose, 🐝 swarm); ❌ marks a service that is explicitly turned off, and ⚙️ an Ansible role dependency declared in `meta/main.yml`.

## Features

- **gVisor runtime:** The pinned `runsc` release is fetched to `/usr/local/bin/runsc` and verified against its published SHA-512 checksum. The Kata shim is taken from the host as it is; the role does not install it.
- **Runtime probing:** The container role checks every host for `/dev/kvm`, for the Kata shim binary and for docker-in-docker, and publishes the resulting choice between `kata` and `runsc` as `SANDBOX_RUNTIME`.
- **Daemon registration:** Only runtimes whose binary is present are written to the daemon configuration, on a bare host and inside docker-in-docker alike. A daemon pointed at an absent runtime path refuses to start, so this role installs first and re-renders the configuration afterwards.
- **Swarm default runtime:** `docker stack deploy` drops the per-service `runtime:` key, so a swarm worker carries the sandbox as its daemon-wide `default-runtime` instead. The stack host keeps the shared kernel for the platform's own services.
- **Node labelling:** In swarm mode the node is labelled `kata-capable=true`, and sandboxed services are constrained to that label. A deploy without a single such node is refused rather than left pending.
- **Runtime pinning:** In compose mode Hermes Agent and OpenClaw pin `SANDBOX_RUNTIME` on their service directly.

## Quick Setup

### Development

Clone, set up the workstation, and deploy Kata & gVisor onto the local stack:

```bash
git clone https://github.com/infinito-nexus/core.git
cd core
make onboard
make compose-deploy mode=reinstall apps=svc-virt-kata full_cycle=false
```

### Production

Install Kata & gVisor directly onto the target machine: clone the repository, install the OS prerequisites and the repository toolchain, then deploy against localhost over a local connection (no SSH, no container):

```bash
git clone https://github.com/infinito-nexus/core.git
cd core
bash scripts/install/package.sh
make install
source scripts/meta/env/load.sh

APP=svc-virt-kata
DOMAIN=<your-domain>
TLS_MODE=self_signed
SSH_PUBLIC_KEY="<your-ssh-public-key>"
INVENTORY=inventories/production
infinito administration inventory provision "$INVENTORY" \
  --inventory-file "$INVENTORY/devices.yml" \
  --host localhost \
  --include "$APP" \
  --vars "{\"TLS_MODE\": \"$TLS_MODE\", \"DOMAIN_PRIMARY\": \"$DOMAIN\", \"users\": {\"administrator\": {\"authorized_keys\": [\"$SSH_PUBLIC_KEY\"]}}}"
infinito administration deploy dedicated "$INVENTORY/devices.yml" \
  --password-file "$INVENTORY/.password" \
  --diff -vv
```

## Credits

Implemented by **[Kevin Veen-Birkenbach](https://www.veen.world)**.
Part of the [Infinito.Nexus Project](https://s.infinito.nexus/code) and maintained by [Kevin Veen-Birkenbach](https://www.veen.world).
Licensed under the [Infinito.Nexus Community License (Non-Commercial)](https://s.infinito.nexus/license).