When platform-install starts, it is assumed that gradelew fetch has already been run on the cord repo, fetching the necessary subrepositories for CORD. This includes fetching the platform-install repository.
For the purposes of this document, paths are relative to the root of the platform-install repo unless specified otherwise. When starting from the uber-cord repo, platform-install is usually located at /cord/components/platform-install.
Platform-install uses a configuration file, config/default.yml, that contains several variables that will be passed to Ansible playbooks. Notable variables include the IP address of the target machine and user account information for SSHing into the target machine. There's also an extra-variable, on-cloudlab that will trigger additional cloudlab-specific actions to run.
Cloudlab nodes boot with small disk partitions setup, and most of the disk space unallocated. Setting the variable on-cloudlab in config/default.yml to true will cause actions to be run that will allocate this unallocated space.
The main gradle script is located in build.gradle.
build.gradle includes two notable tasks, deployPlatform and deploySingle. These are for multi-node and single-node pod installs and end up executing the Ansible playbooks cord-head-playbook.yml and cord-single-playbook.yml respectively.
Platform-install makes extensive use of Ansible Roles, and the roles are selected via two playbooks: cord-head-playbook.yml and cord-single-playbook.yml.
They key differences are that:
Ansible roles are located in the roles directory.
Ansible variables are located in the vars directory.
The first step in bringing up the platform is to setup a DNS server. This is done for the single-node install, and for the multi-node install if maas is not used. An apt cache is setup to facilitate package installation in the many VMs that will be setup as part of the platform. Roles executed include:
Assuming a DNS server was setup in the previous step, then the next step is to point the head node to use that DNS server. Roles executed include:
The next step is to prepare the system. This includes such tasks as installing default packages (tmux, vim, etc), configuring editors, etc. Roles executed include:
Next the head node is configured and VMs are created to host the OpenStack and XOS services. Roles executed include:
Finally, we install the appropriate software in the VMs. This is a large, time consuming step since it includes launching the OpenStack services (using juju), launching ONOS, and launching XOS (using service-platform). Roles executed include:
The final ansible role executed by platform-install is to start XOS. This uses the XOS service-profile repository to bring up a stack of CORD services.
For a discussion of how the XOS service-profile system works, please see Dynamic On-boarding System and Service Profiles.