A Jenkins slave orchestration service: will poll the queue of a master Jenkins instance and look for jobs that are stuck and map the labels needed to configured images ready to get created.
Currently supports only OpenStack as a backend for slave nodes.
The intent of the service is to provide multiple backends, although it currently supports OpenStack, while keeping a check on the Jenkins queue.
Configuring the application requires three distinct parts:
provider: The provider key is a dictionary that contains the name of the provider which itself should contain a username and password key. For example this is how it would look for OpenStack:
provider = {
'openstack': {
'username': 'adeza',
'password': '3ebYzVIQEIZv3sj1==',
'auth_url': 'http://openstack.example.com:5000',
'auth_version': '2.0_password',
'service_region': 'main',
'tenant_name': 'ceph-ci',
}
}This service relies heavily on Apache LibCloud , please refer to the compute examples to see what other keys can be used here and common values:
jenkins: The Jenkins section is very simple, it only requires three items: url, user, and token:
jenkins = {
'url': 'http://jenkins.ceph.com',
'user': 'alfredodeza',
'token': 'API_TOKEN',
}nodes: This is where the virtual machines can be configured along with the labels. The labels key is crucial when configuring each node entry in this section because it allows the service to map the labels from the job that is stuck in the Jenkins queue to a configured node in this section. A single node might look like:
nodes = {
'precise-slave': {
'script': dedent("""#!/bin/bash
sudo apt-get update
"""),
'keyname': 'jenkins-slave',
'image_name': 'Ubuntu Trusty (2014.04) cloudimg',
'size': 'm3.xlarge',
'labels': ['amd64', 'x86_64', 'precise', 'trusty', 'wheezy', 'jessie'],
'provider': 'openstack',
'storage': 10
}
}The top-level keys is the name that will be used to register the machine in the cloud provider. The labels is a throwaway value that has no use for the cloud provider (only important to be able to map it to a jenkins job need).
The provider key allows the system to understand that this should map to a configured provider backend.
The storage key is optional and when present will create and attach a volume to the node when creating it. The size of the volume is defined in gigabytes.
Again, this configuration section relies on Apache LibCloud , please refer to the compute examples to see what other keys can be used here and common values.
In order for the service to properly remove a Jenkins node after the inactivity grace period, it needs a way to map back to the provider. The Jenkins API does not provide information about a node that would make it unique, so we rely on a convention when naming the node.
It is particularly important to follow this convention when more than one type of node will be created to cope with demand.
For example, if a node named 'ubuntu' will have to exist more than once, the service will not be able to understand which one of all the 'ubuntu' nodes it needs to delete in the provider.
The convention is to include one of the host's IP addresses onto the name when registering it in Jenkins with a '+' symbol.
For example, a Jenkins slave, that exists with the name: "ubuntu+192.168.1.188" would allow to have as many 'ubuntu' slaves but uniquely identifiable with an IP that can be looked up on the provider's end to match it to the host.
The service will first attempt to map on the name, and failing to do that it will try to use the IP to look it up.
It is up to whatever is registering the node in Jenkins to use this convention if there is a chance of more than one host matching the same name.
The ancient Inca empire didn't use any form of slavery and used a taxation mechanism that mandated public service for all citizens that could perform labor. And thus, this service ensures that nodes will be up and running (and will later be terminated) to do some work.