Karapace

Deterministic, content-addressed container environments for Linux. No root. No daemon.

Karapace builds isolated development environments from declarative TOML manifests using Linux user namespaces and overlay filesystems. Each environment gets a unique identity (blake3 hash) derived from its fully resolved dependencies.

Prerequisites

• Linux with user namespaces (CONFIG_USER_NS=y)
• fuse-overlayfs
• curl
• Optional: crun/runc/youki (OCI backend)

Run karapace doctor to check.

Install

git clone https://github.com/marcoallegretti/karapace.git
cd karapace
cargo build --release
sudo install -Dm755 target/release/karapace /usr/local/bin/karapace

Or via cargo:

cargo install --git https://github.com/marcoallegretti/karapace.git karapace-cli

Usage

# Create a manifest
cat > karapace.toml << 'EOF'
manifest_version = 1

[base]
image = "rolling"

[system]
packages = ["git", "curl"]

[runtime]
backend = "namespace"
EOF

# Build and enter
karapace build
karapace enter <env_id>

# Run a command
karapace exec <env_id> -- git --version

# Snapshot
karapace commit <env_id>
karapace restore <env_id> <snapshot_hash>

See examples/ for more manifests: minimal.toml, dev.toml, gui-dev.toml, ubuntu-dev.toml, rust-dev.toml.

Commands

25 commands. All accept --store <path>, --verbose, --trace. All except tui accept --json.

new <name> [--template] [--force] Generate `karapace.toml`
build [manifest] [--name]       Build environment
rebuild [manifest] [--name]     Destroy + rebuild
enter <id> [-- cmd...]          Enter environment
exec <id> -- <cmd...>           Run command in environment
destroy <id>                    Destroy environment
stop <id>                       Stop running environment
freeze <id>                     Freeze (prevent writes)
archive <id>                    Archive (prevent entry)
list                            List environments
inspect <id>                    Show metadata
diff <id>                       Show overlay changes
snapshots <id>                  List snapshots
commit <id>                     Snapshot overlay
restore <id> <hash>             Restore snapshot
gc [--dry-run]                  Garbage collect
verify-store                    Check store integrity
push <id> [--tag] [--remote]    Push to remote
pull <ref> [--remote]           Pull from remote
rename <id> <name>              Rename environment
doctor                          Check prerequisites
migrate                         Check store version
completions <shell>             Shell completions
man-pages [dir]                 Generate man pages
tui                             Terminal UI

Workspace

9 crates:

karapace-schema     Manifest, normalization, lock file, identity
karapace-store      Objects, layers, metadata, WAL, GC, integrity
karapace-runtime    Backends (namespace/oci/mock), images, security
karapace-core       Engine: lifecycle orchestration
karapace-cli        CLI (25 commands)
karapace-dbus       D-Bus service (optional)
karapace-tui        Terminal UI (optional)
karapace-remote     Remote store client, push/pull
karapace-server     Reference HTTP server

Limitations

• Linux only.
• Layer packing drops: extended attributes, device nodes, hardlinks, SELinux labels, ACLs.
• Base images are content-hashed but not GPG-verified.
• No MAC enforcement (SELinux/AppArmor) inside containers.
• Remote protocol has no authentication yet.

Documentation

• Architecture
• CLI Reference
• Storage Format
• Security Model
• Build and Reproducibility
• Contributing

License

EUPL-1.2