Plan for final machine/system deployment

[smalers]

The updates to the web application and server-side software have been significant (Python 2 to 3, QGIS 2 to 3, etc.) and OWF is now positioned to do the major updates on the SNODAS GCP server. The following are the steps necessary to do the final update (may modify some as it progresses). The goal is to have similar functionality and results as before using current operating system and software.

The update has at its disposal OWF's Amazon cloud services to do testing, and the State's GCP, including SNODAS and OpenCDSS storage buckets. SNODAS uses a Compute Engine instance that needs to be updated in place.

1. OWF is doing development and testing on a local VirtualBox running Ubuntu 20.4, which is the same as the GCP will be updated to.
2. OWF is running multiple years of the system at OWF and pushing results to the OWF AWS S3 bucket. This is being tested with updated Angular SNODAS web application. The local results on the VM and results on S3 bucket are being validated. This will continue until OWF is satisfied that results are OK.
3. Make a snapshot of the GCP VM in case the system needs to be restored to the snapshot. Ideally the update can be completed and the snapshot can be deleted.
4. Make a backup of data/results on the GCP such as in a tar.gz file and save to SNODAS and/or OpenCDSS bucket, and/or OWF computers. These files also can be used for comparison with the current system.
5. Do an in-place update of the GCP computer, stepping from current Ubuntu 16 up to 20.4. The SNODAS system does not rely on any specific OS software so hopefully the update is straightforward.
6. Uninstall/rename old SNODAS software, QGIS, etc. Software installed in versioned folders can remain.
7. Install current SNODAS software and dependencies.
8. Rerun processing on the full period to ensure everything works. Compare the results with old results and results from testing.

The old web application may no longer work because it uses technologies that are incompatible with current standards such as current GeoJSON format. It should be possible to save old results in the SNODAS storage bucket and point the old application to those files. However, it is recommended that the new application is used. Some minor changes to the URL will be needed and will be provided to the State as soon as the files for the new application are deployed to the cloud. The snow season is close to ending so the system can now be updated.