# Zcash CI workers

This folder contains the Ansible playbooks for configuring a fresh OS
installation for use as a Buildbot worker in Zcash's CI.

# Setting up a latent worker on Amazon EC2

- Add a regular (non-latent) worker to the master.cfg for dev-ci.z.cash, and
  deploy the changes.
  - This enables the Ansible playbook to run to completion, ending in the worker
    connecting to the master.

- Start a basic EC2 instance using the template AMI for the target OS.
  - Choose the smallest instance size, it won't be used for building Zcash.

- Figure out which user to log into the instance with.
  - E.g. for the Ubuntu template, use "ubuntu" instead of "root"
  - If you get an Ansible error later with a message like "Failed to connect to
    the host via ssh: Received message too long 1349281121\r\n", that means the
    instance is sending a text string in response to the SSH connection, and the
    Ansible protocol is balking. Try manually logging in with the same
    credentials to diagnose.

- Create `inventory/hosts` containing the following:

    [zcash-ci-worker-unix]
    some-name ansible_host=<INSTANCE_IP> ansible_ssh_user=<USERNAME>

- Run `ansible-playbook -e buildbot_worker_host_template=templates/host.ec2.j2 -i inventory/hosts unix.yml`,
  passing in the worker's Buildbot name and password.
  - After a successful run, the worker should be connected to dev-ci.z.cash and
    visible in its worker list.

- Create an AMI from the instance. This is the worker AMI to put into the
  master.cfg for dev-ci.z.cash.
  - 16 GB of storage should be sufficient.

- SSH into the instance, and edit the worker config to connect to ci.z.cash.

- Create an AMI from the instance. This is the worker AMI to put into the
  master.cfg for ci.z.cash.
  - 16 GB of storage should be sufficient.

- Delete the instance (it is no longer needed).

- Edit the master.cfg to turn the new worker into a latent (using the new AMI
  IDs), add it to the appropriate worker groups, set up new builders etc.
  - Deploy this via the normal PR review process.