Ansible release for BOSH

Merging the power of Ansible orchestration with the awesome software lifecycle management of BOSH

Apart of providing ansible binaries this release offers a way to trigger actions which will run add-on ansible releases on nodes. The idea is be able to run ansible playbooks every time that a new instance is deployed by making use of BOSH hooks to extend its functionality to Ansible to talk with external components of a deployment like LB, DNSs, etc.

Have a look at the ansible-bigiplb-boshrelease to see an example of an add-on which will register the instances of a deployment on the F5 load balancer pool when they are deployed.

Implementation

This Ansible-release defines four jobs:

• ansible: to provide a way to run Ansible in a deployment via the entrypoint /var/vcap/jobs/ansible/bin/run
• ansible-hooks: to automatically trigger playbooks from other add-on releases.
• ansible-distclean: do define errands from add-on releases which will perform clean-up actions for the deployment.
• ansible-deploy: do define errands from add-on releases which will perform additional deploy actions for the deployment.

In order to trigger playbooks, the ansible-hooks jobs implement the BOSH lifecycle entrypoints: pre-start, post-start, post-deploy and drain to call ansible playbooks available from other releases/jobs. ansible-disclean and ansible-deploy are errands jobs to trigger playbooks which run actions outside the vms of a deployment to manage (delete/deploy) external resources.

ansible job can also run as a errand by defining the parameters of the spec. But the important functionality is done by the ansible- * jobs which will look for playbooks from other jobs folder's (/var/vcap/<job>/ansible/) by predefined filename patterns.

All these jobs accepts a parameter (ansible.env) in the manifest to setup enviroment variables for ansible (or inventory script). Also, bosh-inventory program is already included in the release, so you Ansible can use the inventory feature to query Bosh Director about the VMs of a deployment.

Currently the Director does not run post-deploy by default. Use director.enable_post_deploy: true property in Bosh manifest to enable running those scripts.

ansible-hooks

It provides a way to define and run a set of playbooks of an add-on release job, allowing you to define specific playbooks to run on bootstrap nodes (for master/slave setup) or non-bootstrap nodes. The interface which an add-on has to implement in order to be called is defined by the names of the playbooks on the ansible folder:

• *pre-bootstrap.yml: Will run only on the bootstrap node.
• *pre-nobootstrap.yml: Will run only on the non-bootstrap nodes.
• *pre-start.yml: Will run only on all nodes after the *pre-bootstrap.yml or *pre-nobootstrap.yml playbooks.

Then BOSH Director starts the jobs assigned to each the instance using monit.

• *post-bootstrap.yml: Will run only on the bootstrap node after its jobs are running.
• *post-nobootstrap.yml: Will run only on the non-bootstrap nodes after its jobs are running.
• *post-start.yml: Will run only on all nodes after the *post-bootstrap.yml or *post-nobootstrap.yml playbooks.

Bosh Director waits until all post-start scripts are finished and then these playbooks will be launched

• *postdeploy-bootstrap.yml: Will run only on the bootstrap node after all nodes have run all post-start playbooks.
• *postdeploy-nobootstrap.yml: Will run only on the non-bootstrap nodes after all nodes have run all post-start-playbooks.
• *postdeploy.yml: Will run only on all nodes after the *postdeploy-bootstrap.yml or *postdeploy-nobootstrap.yml playbooks.

When a node leaves the deployment, bosh director will trigger *dran.yml playbooks.

Playbooks from jobs of add-on releases are executed lexically ordered, for example, this could be a list for *drain.yml: jobs/zz/ansible/00-drain.yml, jobs/bb/ansible/10-drain.yml, jobs/aa/ansible/99-drain.yml

ansible-distclean

Playbooks will be executed as errand jobs within the deployment. The idea is implement a way to clean up all the external resources used in a deployment. They have to provide an *distclean.yml playbook which will be launched by the errand.

ansible-deploy

The playbooks will be executed also as errand jobs within the deployment. The idea is implement a way to deploy the external resources (not managed by bosh) used in a deployment. They have to provide an *deploy.yml playbook which will be launched by the errand.

Development

After cloning this repository, run:

./bosh_prepare

It will download all sources specified in the spec file (commented out) of each job, then you can create the release with:

./bosh_final_release

and upload to BOSH director:

bosh upload release

Author

Springer Nature Platform Engineering, Jose Riguera Lopez (jose.riguera@springer.com)

Copyright 2017 Springer Nature

License

Apache 2.0 License