Containarium v0.121.0

What changed

Added

• StartBoxRun takes a per-run model and BoxRun reports it (part of #3259) (#3261)

Fixed

• avoid SIGPIPE in downloaded package membership (#3236) (#3255)
• fail closed when an account's authorized_keys cannot be read (refs #3241) (#3268)
• make StopContainer/StartContainer idempotent with typed errors (#3242) (#3245)
• SSH key ownership wording after revocation; eBPF reply-fragment test ordering (#3257)
• use bundled debs as the offline apt archive cache (#3260)
• backup status detects the daemon's managed backup key (#3213) (#3231)
• release a shared key's registry entry on the owner's drop; compare ownership by user_id (#3217) (#3249)

Internal

• cut v0.121.0 — per-run model (crew and box run), idempotent stop/start, SSH key, bundle and offline-install fixes (#3267)

Full diff: v0.120.2...v0.121.0

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Containarium v0.121.0

The open-source, self-hostable, agent-native sandbox.

Binaries

Four binaries ship in this release:

Binary	Where it runs	What it does
containariumd	The host	The platform daemon plus host-side admin commands.
containarium	Your laptop / CI (linux, macOS, windows)	The client CLI: create, list, expose-port, ssh-config, etc. against a server (--server).
mcp-server	Your laptop	The platform MCP — outside-the-box admin (create_container, list_containers, expose_port, list_backends). Wire it into Claude Code / Cursor.
agent-box	Inside each Containarium container	The in-the-box MCP — shell_exec, read_file, write_file, etc. Reached over stdio, typically via SSH.

Quick install (Linux host)

curl -fsSL https://raw.githubusercontent.com/footprintai/containarium/v0.121.0/hacks/install.sh | sudo bash

Manual install (any binary, any platform)

# containariumd daemon (Linux x86_64 host)
curl -L -o /usr/local/bin/containariumd \
  https://github.com/footprintai/containarium/releases/download/v0.121.0/containariumd-linux-amd64
chmod +x /usr/local/bin/containariumd
ln -sf /usr/local/bin/containariumd /usr/local/bin/containarium

# containarium client CLI (your laptop, e.g. macOS arm64)
curl -L -o /usr/local/bin/containarium \
  https://github.com/footprintai/containarium/releases/download/v0.121.0/containarium-darwin-arm64
chmod +x /usr/local/bin/containarium

# Windows: the same client CLI (create/list/ssh/… against a remote server)
# PowerShell:
#   curl.exe -L -o containarium.exe `
#     https://github.com/footprintai/containarium/releases/download/v0.121.0/containarium-windows-amd64.exe

# platform MCP (your laptop, e.g. macOS arm64)
curl -L -o /usr/local/bin/mcp-server \
  https://github.com/footprintai/containarium/releases/download/v0.121.0/mcp-server-darwin-arm64
chmod +x /usr/local/bin/mcp-server

# agent-box (drop into your container image, Linux x86_64)
curl -L -o /usr/local/bin/agent-box \
  https://github.com/footprintai/containarium/releases/download/v0.121.0/agent-box-linux-amd64
chmod +x /usr/local/bin/agent-box

Verify checksums via SHA256SUMS.txt.

SBOMs

Each Linux binary has an SPDX 2.3 SBOM next to it (<binary>-linux-amd64.spdx.json), generated from the shipped file and listed in SHA256SUMS.txt. The container images carry their own SBOM and provenance attestations.

Signatures

Every file on this page has a keyless cosign signature next to it, <file>.sigstore.json, made by this release workflow through GitHub OIDC. Verify with cosign verify-blob --bundle <file>.sigstore.json --certificate-identity https://github.com/FootprintAI/Containarium/.github/workflows/release.yml@refs/tags/v0.121.0 --certificate-oidc-issuer https://token.actions.githubusercontent.com <file>. See docs/security/VERIFYING-RELEASES.md.

Kubernetes (Helm)

Chart version 0.121.0 (installs the v0.121.0 daemon image):

helm install containarium oci://ghcr.io/footprintai/charts/containarium-k8s \
  --version 0.121.0 \
  --set daemon.jwtSecret="$(openssl rand -hex 24)" \
  --set gateway.upstreamKeySecret=sshpiper-upstream-key \
  --set-file gateway.upstreamPublicKey=./sshpiper_upstream.pub

MCP client setup

Wire the platform MCP into Claude Code (~/.claude.json):

{
  "mcpServers": {
    "containarium": {
      "command": "/usr/local/bin/mcp-server",
      "env": {
        "CONTAINARIUM_SERVER_URL": "http://your-host:8080",
        "CONTAINARIUM_JWT_TOKEN": "<your-token>"
      }
    }
  }
}

Wire agent-box for in-the-box file/shell ops:

{
  "mcpServers": {
    "containarium-box": {
      "command": "ssh",
      "args": ["user@your-box", "agent-box"]
    }
  }
}

See README.md for the full agent-native walkthrough.