Production Deployment Notes#

Review the following deployment notes if you are planning to use M⁴OPT in any of the following production applications:

Operations: In a mission operations center or observatory control room for real time, automated planning of observations
HPC Cluster: In a high performance computing cluster for large-scale simulations
Cloud: In a cloud instance or serverless container as part of a web application

Risk Matrix#

We have categorized these deployment notes using a risk matrix, a visualization used in systems engineering to aid in the evaluation of project risks. In the matrix, the likelihood (on the vertical axis) and consequence (on the horizontal axis) are measured from very low to very high. The cells in the matrix are shaded red, yellow, or green: these correspond to high, medium, or low risk.

		Consequence
		Very Low	Low	Moderate	High	Very High
Likelihood	Very High
	High
	Moderate
	Low					CPLEX Memory
	Very Low			Astropy Data Sources		CPLEX License

Deployment Notes#

Astropy Data Sources#

In normal use, M⁴OPT downloads and caches a variety of Astropy-related data sources that may be time-consuming to download or may be unavailable if your network connection is down or if the remote service is down:

Well-known observatory locations for astropy.coordinates.SkyCoord.from_name()
Dust map for m4opt.synphot.extinction.DustExtinction
Precise Earth orientation data for SkyCoord EarthLocation transformations (see Astropy documentation on working offline)
SVO Filter Profile Service Queries (astroquery.svo_fps)

Mitigation

Ensure that you have a reliable Internet connection.
Run m4opt prime once before deployment to download and cache data sources.
Configure the Astroquery cache to never expire. Edit the Astroquery configuration file at $HOME/.astropy/config/astroquery.cfg and add the following line:
```
cache_timeout = -1
```

CPLEX License#

Free versions of CPLEX have a limit on problem size. A full, unlimited problem size, version of CPLEX is required. If the CPLEX license is not correctly configured, then all invocations of the scheduler will fail.

Mitigation

Follow the insructions to install CPLEX. If you are using a “developer subscription” or “download-and-go” style license, then ensure that you have a reliable connection to the Internet for CPLEX to reach IBM’s license server.

CPLEX Memory#

CPLEX’s memory usage grows as it explores potential solutions. By default, there is no limit on how much memory CPLEX may use. For challenging problems, CPLEX may exhaust available memory.

Mitigation

Make sure that you reserve at least 8 GiB, and preferably 16 GiB or more, for running M⁴OPT. Set the --memory command-line option for the m4opt schedule command to at least 4 GiB less than the maximum amount of memory that you want it to use.