Configuration

Nodepool reads its configuration from /etc/nodepool/nodepool.yaml by default. The configuration file follows the standard YAML syntax with a number of sections defined with top level keys. For example, a full configuration file may have the diskimages, labels, and providers sections:

diskimages:
  ...
labels:
  ...
providers:
  ...

Note

The builder daemon creates a UUID to uniquely identify itself and to mark image builds in ZooKeeper that it owns. This file will be named builder_id.txt and will live in the directory named by the images-dir option. If this file does not exist, it will be created on builder startup and a UUID will be created automatically.

The following sections are available. All are required unless otherwise indicated.

webapp

Define the webapp endpoint port and listen address.

Example:

webapp:
  port: 8005
  listen_address: '0.0.0.0'

elements-dir

If an image is configured to use diskimage-builder and glance to locally create and upload images, then a collection of diskimage-builder elements must be present. The elements-dir parameter indicates a directory that holds one or more elements.

Example:

elements-dir: /path/to/elements/dir

images-dir

When we generate images using diskimage-builder they need to be written to somewhere. The images-dir parameter is the place to write them.

Example:

images-dir: /path/to/images/dir

build-log-dir

The builder will store build logs in this directory. It will create one file for each build, named <image>-<build-id>.log; for example, fedora-0000000004.log. It defaults to /var/log/nodepool/builds.

Example:

build-log-dir: /path/to/log/dir

build-log-retention

At the start of each build, the builder will remove old build logs if they exceed a certain number. This option specifies how many will be kept (usually you will see one more, as deletion happens before starting a new build). By default, the last 7 old build logs are kept.

Example:

build-log-retention: 14

zookeeper-servers

Lists the ZooKeeper servers uses for coordinating information between nodepool workers. Example:

zookeeper-servers:
  - host: zk1.example.com
    port: 2181
    chroot: /nodepool

The port key is optional (default: 2181).

The chroot key, used for interpreting ZooKeeper paths relative to the supplied root path, is also optional and has no default.

labels

Defines the types of nodes that should be created. Jobs should be written to run on nodes of a certain label. Example:

labels:
  - name: my-precise
    max-ready-age: 3600
    min-ready: 2
  - name: multi-precise
    min-ready: 2

required

name

Unique name used to tie jobs to those instances.

optional

max-ready-age (int)

Maximum number of seconds the node shall be in ready state. If this is exceeded the node will be deleted. A value of 0 disables this. Defaults to 0.

min-ready (default: 0)

Minimum number of instances that should be in a ready state. Nodepool always creates more nodes as necessary in response to demand, but setting min-ready can speed processing by attempting to keep nodes on-hand and ready for immedate use. min-ready is best-effort based on available capacity and is not a guaranteed allocation. The default of 0 means that nodepool will only create nodes of this label when there is demand. Set to -1 to have the label considered disabled, so that no nodes will be created at all.

max-hold-age

Maximum number of seconds a node shall be in “hold” state. If this is exceeded the node will be deleted. A value of 0 disables this. Defaults to 0.

This setting is applied to all nodes, regardless of label or provider.

diskimages

This section lists the images to be built using diskimage-builder. The name of the diskimage is mapped to the diskimages section of the provider, to determine which providers should received uploads of each image. The diskimage will be built in every format required by the providers with which it is associated. Because Nodepool needs to know which formats to build, if the diskimage will only be built if it appears in at least one provider.

To remove a diskimage from the system entirely, remove all associated entries in diskimages and remove its entry from diskimages. All uploads will be deleted as well as the files on disk.

Example configuration:

diskimages:
  - name: ubuntu-precise
    pause: False
    rebuild-age: 86400
    elements:
      - ubuntu-minimal
      - vm
      - simple-init
      - openstack-repos
      - nodepool-base
      - cache-devstack
      - cache-bindep
      - growroot
      - infra-package-needs
    release: precise
    username: zuul
    env-vars:
      TMPDIR: /opt/dib_tmp
      DIB_CHECKSUM: '1'
      DIB_IMAGE_CACHE: /opt/dib_cache
      DIB_APT_LOCAL_CACHE: '0'
      DIB_DISABLE_APT_CLEANUP: '1'
      FS_TYPE: ext3
  - name: ubuntu-xenial
    pause: True
    rebuild-age: 86400
    formats:
      - raw
      - tar
    elements:
      - ubuntu-minimal
      - vm
      - simple-init
      - openstack-repos
      - nodepool-base
      - cache-devstack
      - cache-bindep
      - growroot
      - infra-package-needs
    release: precise
    username: ubuntu
    env-vars:
      TMPDIR: /opt/dib_tmp
      DIB_CHECKSUM: '1'
      DIB_IMAGE_CACHE: /opt/dib_cache
      DIB_APT_LOCAL_CACHE: '0'
      DIB_DISABLE_APT_CLEANUP: '1'
      FS_TYPE: ext3

required

name

Identifier to reference the disk image in diskimages and labels.

optional

formats (list)

The list of formats to build is normally automatically created based on the needs of the providers to which the image is uploaded. To build images even when no providers are configured or to build additional formats which you know you may need in the future, list those formats here.

rebuild-age

If the current diskimage is older than this value (in seconds), then nodepool will attempt to rebuild it. Defaults to 86400 (24 hours).

release

Specifies the distro to be used as a base image to build the image using diskimage-builder.

elements (list)

Enumerates all the elements that will be included when building the image, and will point to the elements-dir path referenced in the same config file.

env-vars (dict)

Arbitrary environment variables that will be available in the spawned diskimage-builder child process.

pause (bool)

When set to True, nodepool-builder will not build the diskimage.

username (string)

The username that a consumer should use when connecting onto the node. Defaults to zuul.

providers

Lists the providers Nodepool should use. Each provider is associated to a driver listed below.

required

name

optional

driver

Default to openstack

max-concurrency

Maximum number of node requests that this provider is allowed to handle concurrently. The default, if not specified, is to have no maximum. Since each node request is handled by a separate thread, this can be useful for limiting the number of threads used by the nodepool-launcher daemon.

OpenStack driver

Within each OpenStack provider the available Nodepool image types are defined (see diskimages).

An OpenStack provider’s resources are partitioned into groups called “pools” (see pools for details), and within a pool, the node types which are to be made available are listed (see labels for details).

Example:

providers:
  - name: provider1
    driver: openstack
    cloud: example
    region-name: 'region1'
    rate: 1.0
    boot-timeout: 120
    launch-timeout: 900
    launch-retries: 3
    image-name-format: '{image_name}-{timestamp}'
    hostname-format: '{label.name}-{provider.name}-{node.id}'
    diskimages:
      - name: trusty
        meta:
            key: value
            key2: value
      - name: precise
      - name: devstack-trusty
    pools:
      - name: main
        max-servers: 96
        availability-zones:
          - az1
        networks:
          - some-network-name
        labels:
          - name: trusty
            min-ram: 8192
            diskimage: trusty
            console-log: True
          - name: precise
            min-ram: 8192
            diskimage: precise
          - name: devstack-trusty
            min-ram: 8192
            diskimage: devstack-trusty
  - name: provider2
    driver: openstack
    cloud: example2
    region-name: 'region1'
    rate: 1.0
    image-name-format: '{image_name}-{timestamp}'
    hostname-format: '{label.name}-{provider.name}-{node.id}'
    diskimages:
      - name: precise
        meta:
            key: value
            key2: value
    pools:
      - name: main
        max-servers: 96
        labels:
          - name: trusty
            min-ram: 8192
            diskimage: trusty
          - name: precise
            min-ram: 8192
            diskimage: precise
          - name: devstack-trusty
            min-ram: 8192
            diskimage: devstack-trusty

required

cloud Name of a cloud configured in clouds.yaml.

The instances spawned by nodepool will inherit the default security group of the project specified in the cloud definition in clouds.yaml. This means that when working with Zuul, for example, SSH traffic (TCP/22) must be allowed in the project’s default security group for Zuul to be able to reach instances.

More information about the contents of clouds.yaml can be found in the os-client-config documentation.

optional

boot-timeout

Once an instance is active, how long to try connecting to the image via SSH. If the timeout is exceeded, the node launch is aborted and the instance deleted.

In seconds. Default 60.

launch-timeout

The time to wait from issuing the command to create a new instance until that instance is reported as “active”. If the timeout is exceeded, the node launch is aborted and the instance deleted.

In seconds. Default 3600.

nodepool-id (deprecated)

A unique string to identify which nodepool instances is using a provider. This is useful if you want to configure production and development instances of nodepool but share the same provider.

Default None

launch-retries

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

Default 3.

region-name

hostname-format

Hostname template to use for the spawned instance. Default {label.name}-{provider.name}-{node.id}

image-name-format

Format for image names that are uploaded to providers. Default {image_name}-{timestamp}

rate

In seconds, amount to wait between operations on the provider. Defaults to 1.0.

clean-floating-ips

If it is set to True, nodepool will assume it is the only user of the OpenStack project and will attempt to clean unattached floating ips that may have leaked around restarts.

pools

A pool defines a group of resources from an OpenStack provider. Each pool has a maximum number of nodes which can be launched from it, along with a number of cloud-related attributes used when launching nodes.

Example:

pools:
  - name: main
    max-servers: 96
    availability-zones:
      - az1
    networks:
      - some-network-name
    auto-floating-ip: False
    labels:
      - name: trusty
        min-ram: 8192
        diskimage: trusty
        console-log: True
      - name: precise
        min-ram: 8192
        diskimage: precise
      - name: devstack-trusty
        min-ram: 8192
        diskimage: devstack-trusty

required

name

optional

max-cores

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

max-servers

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

availability-zones (list)

A list of availability zones to use.

If this setting is omitted, nodepool will fetch the list of all availability zones from nova. To restrict nodepool to a subset of availability zones, supply a list of availability zone names in this setting.

Nodepool chooses an availability zone from the list at random when creating nodes but ensures that all nodes for a given request are placed in the same availability zone.

networks (list)

Specify custom Neutron networks that get attached to each node. Specify the name or id of the network as a string.

auto-floating-ip (bool)

Specify custom behavior of allocating floating ip for each node. When set to False, nodepool-launcher will not apply floating ip for nodes. When zuul instances and nodes are deployed in the same internal private network, set the option to False to save floating ip for cloud provider. The default value is True.

diskimages

Each entry in a provider’s diskimages section must correspond to an entry in diskimages. Such an entry indicates that the corresponding diskimage should be uploaded for use in this provider. Additionally, any nodes that are created using the uploaded image will have the associated attributes (such as flavor or metadata).

If an image is removed from this section, any previously uploaded images will be deleted from the provider.

Example configuration:

diskimages:
  - name: precise
    pause: False
    meta:
        key: value
        key2: value
  - name: windows
    connection-type: winrm

required

name

Identifier to refer this image from labels and diskimages sections.

optional

pause (bool)

When set to True, nodepool-builder will not upload the image to the provider.

config-drive (boolean)

Whether config drive should be used for the image. Defaults to unset which will use the cloud’s default behavior.

meta (dict)

Arbitrary key/value metadata to store for this server using the Nova metadata service. A maximum of five entries is allowed, and both keys and values must be 255 characters or less.

connection-type (string)

The connection type that a consumer should use when connecting onto the node. For most diskimages this is not necessary. However when creating Windows images this could be ‘winrm’ to enable access via ansible.

cloud-images

Each cloud-image entry in labels refers to an entry in this section. This is a way for modifying launch parameters of the nodes (currently only config-drive).

Example configuration:

cloud-images:
  - name: trusty-external
    config-drive: False
  - name: windows-external
    connection-type: winrm

required

name

Identifier to refer this cloud-image from labels section. Since this name appears elsewhere in the nodepool configuration file, you may want to use your own descriptive name here and use one of image-id or image-name to specify the cloud image so that if the image name or id changes on the cloud, the impact to your Nodepool configuration will be minimal. However, if neither of those attributes are provided, this is also assumed to be the image name or ID in the cloud.

optional

config-drive (boolean)

Whether config drive should be used for the cloud image. Defaults to unset which will use the cloud’s default behavior.

image-id (str)

If this is provided, it is used to select the image from the cloud provider by ID, rather than name. Mutually exclusive with image-name.

image-name (str)

If this is provided, it is used to select the image from the cloud provider by this name or ID. Mutually exclusive with image-id.

username (str)

The username that a consumer should use when connecting onto the node.

connection-type (str)

The connection type that a consumer should use when connecting onto the node. For most diskimages this is not necessary. However when creating Windows images this could be ‘winrm’ to enable access via ansible.

labels

Each entry in a pool`s labels section indicates that the corresponding label is available for use in this pool. When creating nodes for a label, the flavor-related attributes in that label’s section will be used.

Example configuration:

labels:
  - name: precise
    min-ram: 8192
    flavor-name: 'something to match'
    console-log: True

required

name

Identifier to refer this image from labels and diskimages sections.

one of

diskimage

Refers to provider’s diskimages, see diskimages.

cloud-image

Refers to the name of an externally managed image in the cloud that already exists on the provider. The value of cloud-image should match the name of a previously configured entry from the cloud-images section of the provider. See cloud-images.

at least one of

flavor-name

Name or id of the flavor to use. If min-ram is omitted, it must be an exact match. If min-ram is given, flavor-name will be used to find flavor names that meet min-ram and also contain flavor-name.

min-ram

Determine the flavor to use (e.g. m1.medium, m1.large, etc). The smallest flavor that meets the min-ram requirements will be chosen.

optional

boot-from-volume (bool)

If given, the label for use in this pool will create a volume from the image and boot the node from it.

Default: False

key-name

If given, is the name of a keypair that will be used when booting each server.

console-log (default: False)

On the failure of the ssh ready check, download the server console log to aid in debuging the problem.

volume-size

When booting an image from volume, how big should the created volume be.

In gigabytes. Default 50.

Static driver

The static provider driver is used to define static nodes. Nodes are also partitioned into groups called “pools” (see static nodes for details).

Example:

providers:
  - name: static-rack
    driver: static
    pools:
      - name: main
        nodes:
          - name: trusty.example.com
            labels: trusty-static
            host-key: fake-key
            timeout: 13
            ssh-port: 22022
            username: zuul
            max-parallel-jobs: 1

static nodes

Each entry in a pool`s nodes section indicates a static node and it’s corresponding label.

required

name The hostname or ip address of the static node.

labels (list) The list of labels associated with the node.

optional

username The username nodepool will use to validate it can connect to the node. Default to zuul

timeout The timeout in second before the ssh ping is considered failed. Default to 5 seconds

host-key The ssh host key of the node.

ssh-port The ssh port, default to 22

max-parallel-jobs The number of jobs that can run in parallel on this node, default to 1.