nodepool/doc/source/kubernetes.rst

zuul

Kubernetes Driver

Selecting the kubernetes driver adds the following options to the providers section of the configuration.

providers.[kubernetes]

A Kubernetes provider's resources are partitioned into groups called pools (see providers.[kubernetes].pools for details), and within a pool, the node types which are to be made available are listed (see providers.[kubernetes].pools.labels for details).

Note

For documentation purposes the option names are prefixed providers.[kubernetes] to disambiguate from other drivers, but [kubernetes] is not required in the configuration (e.g. below providers.[kubernetes].pools refers to the pools key in the providers section when the kubernetes driver is selected).

Example:

providers:
  - name: kubespray
    driver: kubernetes
    context: admin-cluster.local
    pools:
      - name: main
        labels:
          - name: kubernetes-namespace
            type: namespace
          - name: pod-fedora
            type: pod
            image: docker.io/fedora:28

context

Name of the context configured in kube/config.

Before using the driver, Nodepool either needs a kube/config file installed with a cluster admin context, in which case this setting is required, or if Nodepool is running inside Kubernetes, this setting and the kube/config file may be omitted and Nodepool will use a service account loaded from the in-cluster configuration path.

launch-retries

The number of times to retry launching a node before considering the job failed.

pools

A pool defines a group of resources from a Kubernetes provider.

name

Namespaces are prefixed with the pool's name.

priority

The priority of this provider pool (a lesser number is a higher priority). Nodepool launchers will yield requests to other provider pools with a higher priority as long as they are not paused. This means that in general, higher priority pools will reach quota first before lower priority pools begin to be used.

This setting may be specified at the provider level in order to apply to all pools within that provider, or it can be overridden here for a specific pool.

node-attributes

A dictionary of key-value pairs that will be stored with the node data in ZooKeeper. The keys and values can be any arbitrary string.

max-cores

Maximum number of cores usable from this pool. This can be used to limit usage of the kubernetes backend. If not defined nodepool can use all cores up to the limit of the backend.

max-servers

Maximum number of pods spawnable from this pool. This can be used to limit the number of pods. If not defined nodepool can create as many servers the kubernetes backend allows.

max-ram

Maximum ram usable from this pool. This can be used to limit the amount of ram allocated by nodepool. If not defined nodepool can use as much ram as the kubernetes backend allows.

default-label-cpu

Only used by the providers.[kubernetes].pools.labels.type.pod label type; specifies specifies a default value for providers.[kubernetes].pools.labels.cpu for all labels of this pool that do not set their own value.

default-label-memory

Only used by the providers.[kubernetes].pools.labels.type.pod label type; specifies a default value for providers.[kubernetes].pools.labels.memory for all labels of this pool that do not set their own value.

labels

Each entry in a pool`s labels section indicates that the corresponding label is available for use in this pool.

Each entry is a dictionary with the following keys

name

Identifier for this label; references an entry in the labels section.

type

The Kubernetes provider supports two types of labels:

namespace

Namespace labels provide an empty namespace configured with a service account that can create pods, services, configmaps, etc.

pod

Pod labels provide a dedicated namespace with a single pod created using the providers.[kubernetes].pools.labels.image parameter and it is configured with a service account that can exec and get the logs of the pod.

image

Only used by the providers.[kubernetes].pools.labels.type.pod label type; specifies the image name used by the pod.

image-pull

The ImagePullPolicy, can be IfNotPresent, Always or Never.

python-path

The path of the default python interpreter. Used by Zuul to set ansible_python_interpreter. The special value auto will direct Zuul to use inbuilt Ansible logic to select the interpreter on Ansible >=2.8, and default to /usr/bin/python2 for earlier versions.

shell-type

The shell type of the node's default shell executable. Used by Zuul to set ansible_shell_type. This setting should only be used

• For a windows pod with the experimental connection-type ssh, in which case cmd or powershell should be set and reflect the node's DefaultShell configuration.
• If the default shell is not Bourne compatible (sh), but instead e.g. csh or fish, and the user is aware that there is a long-standing issue with ansible_shell_type in combination with become

cpu

Only used by the providers.[kubernetes].pools.labels.type.pod label type; specifies the number of cpu to request for the pod.

memory

Only used by the providers.[kubernetes].pools.labels.type.pod label type; specifies the amount of memory in MB to request for the pod.

env

Only used by the providers.[kubernetes].pools.labels.type.pod label type; A list of environment variables to pass to the Pod.

name

The name of the environment variable passed to the Pod.

value

The value of the environment variable passed to the Pod.

node-selector

Only used by the providers.[kubernetes].pools.labels.type.pod label type; A map of key-value pairs to ensure the Kubernetes scheduler places the Pod on a node with specific node labels.