Postgres wrapper (zenith_ctl) is intended to be run as a Docker entrypoint or as a systemd ExecStart option. It will handle all the zenith specifics during compute node initialization:

zenith_ctl accepts cluster (compute node) specification as a JSON file.
Every start is a fresh start, so the data directory is removed and initialized again on each run.
Next it will put configuration files into the PGDATA directory.
Sync safekeepers and get commit LSN.
Get basebackup from pageserver using the returned on the previous step LSN.
Try to start postgres and wait until it is ready to accept connections.
Check and alter/drop/create roles and databases.
Hang waiting on the postmaster process to exit.

Also zenith_ctl spawns two separate service threads:

compute-monitor checks the last Postgres activity timestamp and saves it into the shared ComputeState;
http-endpoint runs a Hyper HTTP API server, which serves readiness and the last activity requests.

Usage example:

zenith_ctl -D /var/db/postgres/compute \
           -C 'postgresql://zenith_admin@localhost/postgres' \
           -S /var/db/postgres/specs/current.json \
           -b /usr/local/bin/postgres

Tests

Cargo formatter:

cargo fmt

Run tests:

cargo test

Clippy linter:

cargo clippy --all --all-targets -- -Dwarnings -Drust-2018-idioms

Cross-platform compilation

Imaging that you are on macOS (x86) and you want a Linux GNU (x86_64-unknown-linux-gnu platform in rust terminology) executable.

Using docker

You can use a throw-away Docker container (rustlang/rust image) for doing that:

docker run --rm \
    -v $(pwd):/compute_tools \
    -w /compute_tools \
    -t rustlang/rust:nightly cargo build --release --target=x86_64-unknown-linux-gnu

or one-line:

docker run --rm -v $(pwd):/compute_tools -w /compute_tools -t rust:latest cargo build --release --target=x86_64-unknown-linux-gnu

Using rust native cross-compilation

Another way is to add x86_64-unknown-linux-gnu target on your host system:

rustup target add x86_64-unknown-linux-gnu

Install macOS cross-compiler toolchain:

brew tap SergioBenitez/osxct
brew install x86_64-unknown-linux-gnu

And finally run cargo build:

CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=x86_64-unknown-linux-gnu-gcc cargo build --target=x86_64-unknown-linux-gnu --release