worker/docs/source-installation.md

SSH Source Installation Plan

Status

In progress. Work package 1 (reusable Docker/OpenSSH harness and distro fixtures) and the pure detection/planning foundation (work package 2 core) are implemented:

• internal/installer/harness builds and runs real OpenSSH containers for Alpine, Ubuntu, and Arch, waits for real network readiness, captures the server host key into a temp known_hosts file, and tears the container, network, per-instance fixture image tag, and temp dir down reliably. It never mocks SSH and connects with the golang.org/x/crypto/ssh library and known_hosts verification semantics the installer's deploy path relies on.
• internal/sshinstall resolves a remote host's distro, package manager, and init system from /etc/os-release, plans the pinned Go 1.26 toolchain (published SHA-256) for the remote architecture, and produces a pure source-install plan. It executes nothing.

The current Go installer can still only upload a binary or deploy an immutable Docker image over SSH. Remote package/toolchain/source build execution (work packages 3 and 4) is not implemented yet; the acceptance test currently stops after detection, clean-state, and planning assertions. Existing tests are unit tests; the harness tests run against live OpenSSH containers when explicitly enabled.

Initial Platform Scope

The first source installer supports Linux and is validated on Alpine, Ubuntu, and Arch Linux containers. CentOS-family support follows after its package and service differences are implemented. Windows and macOS remain later platform work despite the worker being written in Go.

Use reg.rsxx.ru image mirrors where available. Tests must not depend on Docker Hub when a local mirror exists.

Source Install Flow

The Go CLI connects through golang.org/x/crypto/ssh using existing key, passphrase, password, sudo-password, known-hosts, and pinned-fingerprint support. It then:

1. detects supported OS, architecture, package manager, init system, and privilege path;
2. installs only required packages (git, CA certificates, download/archive tools); it does not install build-essential or a C compiler unless a detected dependency requires CGO;
3. downloads the pinned Go 1.26 toolchain for the detected architecture and verifies the published SHA-256;
4. clones https://rocketgit.ru/rsmon/worker.git or updates an existing clone;
5. checks out branch main and records the resolved commit;
6. builds a reproducible worker binary with the repository build flags;
7. atomically installs the binary, validated environment, data directory, and service definition;
8. starts the service and verifies process status and /healthz.

Repository, branch, Go version, checksum source, build directory, and Go module proxy may be configurable, but production output records their resolved values. The default repository is publicly readable and requires no source credential.

Docker OpenSSH Test Harness

Adapt the real-network pattern from /data/_swap/sshkeymanager: start an OpenSSH container, wait for SSH readiness, connect with the Go installer, and tear the environment down reliably. Do not mock SSH command execution in the acceptance test.

Provide images/fixtures for:

• Ubuntu with apt and systemd-compatible service testing where practical;
• Alpine with apk/OpenRC or a clearly separated no-service build/install gate;
• Arch with pacman and its service behavior.

Each clean target begins without Go or the worker source. The test asserts package installation, verified Go version, clone branch/resolved commit, build, atomic config permissions, running service where supported, and HTTP liveness.

Implementation (internal/installer/harness)

The harness starts one container per distro fixture (testdata/fixtures/{alpine,ubuntu,arch}/Dockerfile), waits for a real TCP + SSH handshake, captures the server host key into a temp known_hosts file, and connects with the golang.org/x/crypto/ssh library and known_hosts verification semantics the installer's deploy uses. The harness owns its connection code rather than calling into the installer package, so the tests stay independent; only the library and the verification semantics are shared.

Host-key handling is trust-on-first-use (TOFU): the fresh temp known_hosts file accepts the first key the server presents. What the harness proves is that a known_hosts entry carrying a different key is rejected before any command runs (the TestHarnessHostKeyMismatch test), not that a fingerprint is pinned.

Teardown (docker rm -f + docker network rm + per-instance docker image rm + temp-dir removal) is idempotent, runs on every Start error path, and is verified by a dedicated test. Each harness instance builds its own uniquely-tagged fixture image (rsmon-worker-test/<fixture>-<suffix>:local), so removing one never deletes a shared base image or another instance's image.

Base images, mirror-first:

Fixture	Default image	Note
alpine	reg.rsxx.ru/library/alpine:3	reg.rsxx.ru mirror exists
ubuntu	ubuntu:24.04	no mirror yet; override RSMON_TEST_IMAGE_UBUNTU
arch	archlinux:latest	no mirror yet; override RSMON_TEST_IMAGE_ARCH

Any RSMON_TEST_IMAGE_<NAME> environment variable overrides the fixture image, so a mirror or local cache can be used when available.

Mutable test images. The fixture base tags above are deliberately mutable (a major-tag mirror ref and Docker Hub rolling tags) so the fixtures track current distro releases. Fixture builds are therefore not byte-reproducible; the worker's source-install production output pins immutable artifacts (a Go toolchain SHA-256, a branch's resolved commit) and this harness's image override is the escape hatch for reproducing a specific distro snapshot.

The fixtures authenticate with the bundled test key (testdata/keys/rsmon_test_ed25519); password auth is disabled and PermitRootLogin is prohibit-password. openrc is installed in the Alpine fixture so init detection has a stable marker; Ubuntu and Arch carry systemd markers.

Test-only key. The bundled keypair is strictly a test fixture: it grants root SSH access only to the disposable containers that bake its public key. It must never be used for real hosts, added to production images, or treated as a credential outside the harness.

Opt-in integration test controls

Ordinary unit runs never pull or start Docker. The Docker/OpenSSH tests are gated behind the RSMON_TEST_DOCKER environment variable:

• make test (default CI unit run) pins RSMON_TEST_DOCKER=0 and skips every harness Docker test, even when the flag is exported in the developer's environment.
• make test-ssh sets RSMON_TEST_DOCKER=1 and runs the full fixture matrix (TestHarnessFixtures for alpine/ubuntu/arch, host-key mismatch, stable host key, failed-start cleanup, and teardown assertions).
• The harness Start itself refuses to run without the opt-in flag.

Run them locally with:

make test-ssh

or, equivalently:

RSMON_TEST_DOCKER=1 go test -v -count=1 -timeout 30m ./internal/installer/harness

Idempotency And Security

• A second run updates/fetches safely and leaves one active service.
• Wrong host fingerprints fail before remote mutation. The harness's fresh known_hosts file is trust-on-first-use; its dedicated mismatch test dials against a known_hosts entry carrying a different server key and proves the dial fails before any command runs.
• Tokens/passwords come from files or stdin-safe channels and never appear in command arguments, logs, source checkout, or shell history.
• Remote temporary files are removed on success and failure.
• Failed builds do not replace a working binary or service definition.
• Package-manager and download failures return bounded actionable errors.
• The installer verifies Go tarball checksum before extraction.

Implementation Work Packages

• 1. Add reusable Docker/OpenSSH harness and distro fixtures.
• 2. Add pure distro/toolchain/source-install script planning and unit tests (detection + planning foundation; remote execution is work package 3).
• 3. Execute source installation through the existing SSH transport.
• 4. Add atomic build/install, idempotency, and failure rollback.
• 5. Add Alpine, Ubuntu, and Arch network E2E tests to CI.
• 6. Add CentOS-family support.
• 7. Plan native Windows service and macOS launchd installers separately.

Acceptance Gates

• All three initial Linux images install from a clean state through OpenSSH.
• The built worker reports the expected version/commit and serves /healthz.
• Re-running the installer succeeds without duplicate services or leaked files.
• Host-key, checksum, clone, build, and service-start failure tests preserve the previous installation.
• CI uses approved registry mirrors and cleans every test container/network.

Verified Test Evidence (work packages 1 and 2)

Recorded 2026-08-12 from make test-ssh (Docker Engine 29.7.1):

• Alpine 3.24.1 (mirror reg.rsxx.ru/library/alpine:3): distro alpine, pkg apk, init openrc.
• Ubuntu 24.04 (VERSION_ID=24.04): distro ubuntu, pkg apt, init systemd.
• Arch rolling image archlinux:latest (VERSION_ID=20260809.0.570793): distro arch, pkg pacman, init systemd.
• Host-key mismatch, host-key stability, failed-start cleanup, and complete teardown (container, network, fixture image tag, and temp dir gone) tests pass; no test container, network, or image tag is left behind.