Configuration

Server-side knobs only. CLI flags on the entry point and one environment variable. Client config lives under Use from Python.

Server-side knobs only: a handful of CLI flags on the neops-remote-lab entry point and a single environment variable that toggles Netlab subprocess streaming. Client-side configuration (REMOTE_LAB_URL plus the three timeouts) lives on its own page under Use from Python → Configuration.

Server CLI flags

The neops-remote-lab entry point is defined in neops_remote_lab/__main__.py:main() and parses the following flags via argparse.

Flag	Default	Description
`--host <addr>`	`0.0.0.0`	Interface to bind. The default binds on all interfaces — only appropriate on trusted networks (see Security model).
`--port <int>`	`8000`	TCP port.
`--log-level <level>`	`INFO`	Python logging level applied to the remote-lab loggers. Case-insensitive (`DEBUG`, `INFO`, `WARNING`, `ERROR`).
`--log-config <path>`	`logging_config.yaml`	Path to a YAML logging config. If the path does not exist, the packaged default is used (`neops_remote_lab/logging_config.yaml`).
`--debug`	off	Enables debug logging and streams Netlab output (see below).
`--version`	—	Print version and exit.

The `--debug` shortcut

--debug performs two side effects on top of normal startup:

Overrides --log-level to DEBUG.
Exports NEOPS_NETLAB_STREAM_OUTPUT=1 into the process environment, so Netlab subprocess output streams to the log in real time.

Equivalent to:

NEOPS_NETLAB_STREAM_OUTPUT=1 neops-remote-lab --log-level DEBUG --port 8000

Launch examples

DefaultVerbose investigationBound to VPN onlyCustom logging config

neops-remote-lab

Binds to 0.0.0.0:8000 with INFO logging and the packaged logging config.

neops-remote-lab --debug --port 8000

DEBUG logging plus live Netlab output. Useful when a topology fails to come up and you want to watch netlab up in the server log.

neops-remote-lab --host 10.0.0.2 --port 8000

Bind to a specific interface — preferred when the host has a public NIC you do not want the server reachable on.

neops-remote-lab --log-config /etc/neops/remote-lab-logging.yaml

Server environment variable

`NEOPS_NETLAB_STREAM_OUTPUT`

When set to the string "1", run_netlab unconditionally enables line-by-line streaming of Netlab subprocess output into the server log at DEBUG level.

Value	Effect
`"1"`	Stream Netlab stdout/stderr live to the logger
unset or anything else	Capture Netlab output and log only on non-zero exit code

The server sets this automatically when you launch it with --debug. Export it manually for one-off investigations without changing the log level.

Server startup prerequisites

The entry point performs two pre-flight checks before binding the HTTP port:

Single-instance lock — see Administration → Single-instance filelock.
Netlab CLI on PATH — if shutil.which("netlab") returns None the server logs the install URL and exits with SystemExit(1) before starting. Install Netlab on the host before starting the server — see Netlab host setup.

What you almost never need to change

Server cleanup cadence — hard-coded in server.py: _SESSION_CLEANUP_INTERVAL = 5, _WAITING_SESSION_TIMEOUT = 600, _ACTIVE_SESSION_STALE = 300. These are not exposed as flags because changing them shifts the FIFO contract that clients depend on; see Session Queue for the reasoning.
Netlab instance name — the server always uses the default Netlab instance and cleans up stale defaults at startup.

If you believe you need to change one of these, open an issue — the one-size-fits-all defaults are deliberate.

Client-side configuration

Client environment variables (REMOTE_LAB_URL plus the three timeout overrides) live on their own page: Use from Python → Configuration. The pytest fixture and RemoteLabClient read those at setup time on the test-runner host, not on the server.