kondunite

Kubernetes Conditional Manifests Unifier

The tool is used to unify Kubernetes manifests targeting a specific release, by using hints in the manifest files.

Currently only yaml manifests are supported.

Tool is written and tested only in Python 3.7

Install

pip install --upgrade kondunite

Usage

Terminology -

• target - a platform for which we might want to apply the manifests to. i.e GKE.
• repl - short for replicated.

Usage: kondunite [OPTIONS] DIRECTORY

Options:
  --no-recurse          Do not recurse manifests directory
  -t, --target TEXT     Conditional target for unification  [required]
  -i, --img TEXT        One or more tag to specific images, provide values in
                        the forms of 'image-name:tag', i.e
                        gcr.io/company/server:1.0
  -b, --repl-base TEXT  Base replicated yaml definition (for '#kind:
                        replicated' section), defaults to
                        <directory>/replicated_base.yaml
  -o, --output TEXT     File to write the unified yaml to, defaults to
                        <target>.yaml
  -r, --repl            Plot output for a replicated release (with '# kind:
                        scheduler-kubernetes' annotations)
  --repl-registry TEXT  One or more docker registries defined in your
                        Replicated settings in the form of endpoint:name, i.e
                        gcr.io/company
  --help                Show this message and exit.

Where DIRECTORY is the path to a directory containing the Kubernetes manifests.

Currently all filenames across all subdirectories must be unique. Only one of the file instances will be picked if this assumption does not hold.

Options

• --img: Used to override image tags in the manifests. Can also be used if the manifests contain only placeholder tags.
• --repl-base: File containing the basic replicated release file definitions. See documentation.
• --repl-registry: Specify the Docker registries to be configured in the replicated release file. See documentation.

Examples

kondunite --target gke -i neo4j:lat3st -i gcr.io/kondunite/test:1.0 ./k8s
kondunite --target repl -i neo4j:late5t -i gcr.io/kondunite/test:1.0 --repl --repl-registry gcr.io/kondunite ./k8s

For more detailed examples see examples.

Manifests Hints

Some hints could be injected to the Kubernetes manifests to utilize the power of this tool.

Noe the hints will make the manifests syntactically invalid by Kubernetes definitions and must be parse by this tool to be applicable.

targetsOnly

Specify at manifest top level that it only targets a specific platform.

targetsOnly: <target>

For example:

apiVersion: v1
kind: PersistentVolumeClaim
targetsOnly: gke
metadata:
  name: pvc
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: ""
  resources:
    requests:
      storage: 17Gi

dependencies

Specify apply-time dependencies for the manifests, meaning which manifest should be applied before which. You can specify one or more.

In case of a circular dependency a toposort.CircularDependencyError will be raised with a descriptive message.

It is assumed that manifests in the same file should maintain their definition order.

dependencies:
  - filename1.yaml
  - filename2.yaml

Currently only filenames are supported (not paths). So if the files in dependency reside in different directories they could still be declared as dependent without specifying their relation. Note recurring filenames are currently not supported.

For example:

apiVersion: v1
kind: PersistentVolumeClaim
dependencies:
  - nfs.yaml
  - pv.yaml
metadata:
  name: pvc
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: ""
  resources:
    requests:
      storage: 17Gi

-<target> yaml node suffix

If any node in a manifest is named with a -<target> suffix, it will be filtered out if the target mismatches the requested target.

The feature is only supported for dict or list nodes, meaning not for low level nodes such as strings etc., except for specific allowed nodes like:

• replicas

Since Kubernetes manifests use only camel casing, a dash character should not appear in any (non low level) node that does not intend to hint on a target.

This hint act similar to targets_only hint, however it applies only to a node and not to a whole manifest.

<node>-<target>:
    ...

For example:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc
spec:
  accessModes-gke:
    - ReadWriteOnce
  accessModes-repl:
    - ReadWriteMany
  storageClassName: ""
  resources:
    requests-gke:
      storage: 17Gi
    requests-repl:
      storage: 7Gi

(Note accessMode and requests nodes)

apiVersion: apps/v1
kind: Deployment
metadata:
  name: neo4j
spec:
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: neo4j
  template:
    metadata:
      labels:
        app: neo4j
    spec:
      containers:
        - name: neo4j
          image: neo4j:latest
          env-repl:
            - name: NEO_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: neo4j
                  key: neo-password
          env-gke:
            - name: NEO_PASSWORD
              value: 'password'

(Note env node)

replKind

Allows a manifest to declare a Replicated kind that is not the default - scheduler-kubernetes.

For example:

apiVersion: v1
kind: Pod
targetsOnly: repl
replKind: preflight-kubernetes
metadata:
  name: disk-space-checker
spec:
  containers:
  - name: tester
    image: busybox
    command: ["sh", "-c", "[ \"$(df -k /host/var | tail -1 | xargs | cut -d' ' -f2)\" -gt \"80000000\" ]"]
    volumeMounts:
    - name: var
      mountPath: /host/var
  volumes:
  - name: var
    hostPath:
      path: /var

Dev Setup

Create a virtualenv: python3 -m venv ./venv

And activate it: source dev.sh

Install requirements: pip install -r requirements.txt

Install package: pip install --editable .

Deployment

Package is deployed using Google Cloud Build. See cloudbuild.yaml.

Any push to master branch will trigger a push to pypi if package version was increased.

For a push to any branch, a sanity wheel build will run.