内容简介:In theprevious post we saw how we can create a Kubernetes Manifest from a Ruby Hash. However, to check we don’t add incorrect values we have to write detailed tests. Can we automate that in any way? Yes, we can.Fortunately it is very easy to get the type a
Story So Far
In theprevious post we saw how we can create a Kubernetes Manifest from a Ruby Hash. However, to check we don’t add incorrect values we have to write detailed tests. Can we automate that in any way? Yes, we can.
Fortunately it is very easy to get the type and layout of the resources Kubernetes uses directly from the Kubernetes server.
Enter OpenAPI
$ kubectl get --raw /openapi/v2
This will obtain the OpenAPI definitions of all the resources installed on the Kubernetes Cluster. All we need to do is translate the OpenAPI definition into a Ruby library we can use.
We can do that with a Makefile
Remember Make?
vendor: kubernetes-client bundle install --clean --without development test --deployment kubernetes-client: kubeapi.json docker run --rm -v $(CURDIR):/local \ -u $(shell id -u $(USER)):$(shell id -g $(USER)) \ openapitools/openapi-generator-cli generate \ -g ruby \ -p "moduleName=Kubernetes" \ -i /local/$< \ -o /local/$@ kubeapi.json: kubectl get --raw /openapi/v2 > $@ .PHONY: clean clean: rm -rf kubernetes-client kubeapi.json vendor
then tie it all together via the Gemfile
gemspec path: File.expand_path('kubernetes-client', __dir__) source 'https://rubygems.org' gem 'activesupport', '~> 6.0'
Build the library with make
and we have a typed Ruby library ready to
use - precisely tailored to the resources on your Kubernetes cluster.
Use the Generated Library
Now let’s change the create_job_manifest
method from last time to use
the types from the generated OpenAPI library.
def create_job_manifest(release, config, version, name) Kubernetes::IoK8sApiBatchV1Job.new( api_version: 'batch/v1', kind: 'Job', metadata: Kubernetes::IoK8sApimachineryPkgApisMetaV1ObjectMeta.new( name: name, labels: { build: config[:prefix] } ), spec: Kubernetes::IoK8sApiBatchV1JobSpec.new( ttl_seconds_after_finished: config[:holdTime], template: Kubernetes::IoK8sApiCoreV1PodTemplateSpec.new( spec: Kubernetes::IoK8sApiCoreV1PodSpec.new( restart_policy: 'Never', containers: [ Kubernetes::IoK8sApiCoreV1Container.new( name: name, image: config[:image], resources: Kubernetes::IoK8sApiCoreV1ResourceRequirements.new( requests: { memory: config[:requestsMemory], cpu: config[:requestsCpu] }, limits: { memory: config[:limitsMemory], cpu: config[:limitsCpu] } ), args: [ '--dockerfile=Dockerfile', "--context=#{config[:gitRepo]}#refs/heads/release-#{release}", "--destination=#{config[:dockerTarget]}:#{version}" ], volume_mounts: [ Kubernetes::IoK8sApiCoreV1VolumeMount.new( name: config[:secretName], fred: 'boo', mount_path: '/root' ) ] ) ], volumes: [ Kubernetes::IoK8sApiCoreV1Volume.new( name: config[:secretName], secret: Kubernetes::IoK8sApiCoreV1SecretVolumeSource.new( secret_name: config[:secretName], items: [ Kubernetes::IoK8sApiCoreV1KeyToPath.new( key: '.dockerconfigjson', path: '.docker/config.json' ) ] ) ) ] ) ) ) ) end
update the spec to use ‘dot format’ access.
describe '#create_job_manifest' do let(:job) { load 'create_docker_jobs' create_job_manifest('1.16', config, '1.16.1', 'job-1.16') } it 'has a restart Policy of never' do expect(job.spec.template.spec.restart_policy).to eq 'Never' end end
And Test
Run the spec with rspec
$ bundle install --with development $ bundle exec rspec F Failures: 1) #create_job_manifest has a restart Policy of never Failure/Error: load 'create_docker_jobs' ArgumentError: `fred` is not a valid attribute in `Kubernetes::IoK8sApiCoreV1VolumeMount`. Please check the name to make sure its valid. List of attributes: [:mount_path, :mount_propagation, :name, :read_only, :sub_path, :sub_path_expr] ...
Whoops. How did that get in there?
Can We Do More?
Now we have typed manifests that we can manipulate easily within Ruby, but
we still have to remember the names of the types. If you can remember that metadata
is IoK8sApimachineryPkgApisMetaV1ObjectMeta
, you’re doing
better than me. Remembering stuff like that is what we have computers for.
Reflect on that, and we’ll see what we can do about it in the next post. Stay tuned.
Postscript
Kubernetes knows about the resources it wants, therefore the best way to get the resources correct is to ask Kubernetes what it wants to see.
Fortunately, with the OpenAPI interface and the generators that can use that interface to create code libaries that match our cluster precisely, we can easily incorporate those resource specifications in our Ruby code with ease.
Interested in Managed Kubernetes?
Brightbox have been managing web deployments large and small for over a decade. If you’re interested in the benefits of Kubernetes but want us to handle managing and monitoring it for you,drop us a line.
以上所述就是小编给大家介绍的《Rubynetes: Using OpenAPI to validate Kubernetes configs》,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持!
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