traas is a set of Heat templates and wrapper scripts arond toci_gate_test.sh. You can think of traas as taking on the role that is done by nodepool and devstack-gate in CI, but using Heat instead. traas could just be used when you have access to an OpenStack cloud with Heat that you want to use for TripleO development.
The Heat templates are used to bring up a multinode environment, and then trigger some SoftwareDeployment resources on the undercloud node to execute a tripleo-ci job.
The main template is:
templates/traas.yaml
You can see the resources there for an undercloud node and set of overcloud nodes, etc. The templates requires some parameters. Included, there are some sample environment files that can be used to set the required parameters at:
templates/example-environments
Once the nodes are up, the main script that is triggered is:
scripts/traas.sh
The script logs to tripleo-root/traas.log in the home directory of the centos user. This logfile is equivalent to the upstream console.html output from a ci job.
That is a simple wrapper around toci_gate_test.sh. The $TOCI_JOBTYPE variable (passed in via a Heat parameter) is what drives which job is executed. Since it just executes toci_gate_test.sh, what tool tripleo-ci uses for that jobtype is what tool gets used to execute the job (tripleo-quickstart, tripleo.sh, etc).
By default, it will be set to multinode-1ctlr-featureset004 which is the default nonha multinode job used upstream in tripleo-ci.
It executes the ci job end to end and then leaves the environment up at the end for inspection and/or development.