nexus-pcv

A CLI tool to perform a pre-change validation on Nexus Dashboard Insights. It can either work with provided JSON file(s) or a terraform plan output from a Nexus as Code project. It waits for the analysis to complete and evaluates the results.

$ nexus-pcv -h
Usage: nexus-pcv [OPTIONS]

  A CLI tool to perform a pre-change validation on Nexus Dashboard Insights.

Options:
  --version                  Show the version and exit.
  -v, --verbosity LVL        Either CRITICAL, ERROR, WARNING, INFO or DEBUG.
  -i, --hostname-ip TEXT     ND hostname or IP (required, env:
                             PCV_HOSTNAME_IP).
  -u, --username TEXT        ND username (required, env: PCV_USERNAME).
  -p, --password TEXT        ND password (required, env: PCV_PASSWORD).
  -d, --domain TEXT          ND login domain (optional, default: 'local', env:
                             PCV_DOMAIN).
  -g, --group TEXT           NDI insights group name (optional, default:
                             'default', env: PCV_GROUP).
  -s, --site TEXT            NDI site or fabric name (required, env:
                             PCV_SITE).
  -n, --name TEXT            NDI pre-change validation name (optional, env:
                             PCV_NAME).
  --suppress-events TEXT     NDI comma-separated list of events to suppress
                             (optional, default: 'APP_EPG_NOT_DEPLOYED,APP_EPG
                             _HAS_NO_CONTRACT_IN_ENFORCED_VRF', env:
                             PCV_SUPPRESS_EVENTS).
  --timeout INTEGER          NDI pre-change validation timeout in minutes
                             (optional, default: 15, env: PCV_TIMEOUT).
  -f, --file FILE            NDI proposed change JSON file (optional, env:
                             PCV_FILE).
  -t, --nac-tf-plan FILE     NDI proposed change Terraform plan output
                             (optional, env: PCV_NAC_TF_PLAN).
  -o, --output-summary FILE  NDI summary of new events/anomalies written to a
                             file (optional, env: PCV_OUTPUT_SUMMARY).
  -r, --output-url FILE      NDI link (URL) to pre-change validation results
                             written to a file (optional, env:
                             PCV_OUTPUT_URL).
  -h, --help                 Show this message and exit.

Installation

Python 3.7+ is required to install nexus-pcv. Don't have Python 3.7 or later? See Python 3 Installation & Setup Guide.

nexus-pcv can be installed in a virtual environment using pip:

pip install nexus-pcv

CI/CD Integration

The tool can easily be integrated with CI/CD workflows. Arguments can either be provided via command line or environment variables. The tool will exit with a non-zero exit code in case of an error or non-suppressed events being discovered during the pre-change analysis. The --output-summary and --output-url arguments can be used to write a summary and/or a link (URL) to a file, which can then be embedded into notifications (e.g., Webex).

Nexus as Code Integration

Nexus as Code allows users to instantiate network fabrics in minutes using an easy to use, opinionated data model. More information about Nexus as Code can be found here. A planned change can be validated before applying it to a production environment by running a terraform plan operation first and then providing the output to nexus-pcv to trigger a pre-change validation.

export PCV_HOSTNAME_IP=10.1.1.1
export PCV_USERNAME=admin
export PCV_PASSWORD=Cisco123
export PCV_GROUP=LAB
export PCV_SITE=LAB1
terraform plan -out=plan.tfplan
terraform show -json plan.tfplan > plan.json
nexus-pcv --name "PCV1" --nac-tf-plan plan.json