Kubernetes Resource

The Kubernetes resource check creates kubernetes resources based on the provided manifests & perform checks on them. Some common use case of this check would be to see if a service is accessible via the ingress as shown in the example below.

ingress_test.yaml
---
apiVersion: canaries.flanksource.com/v1
kind: Canary
metadata:
  name: ingress-test
  namespace: default
  labels:
    "Expected-Fail": "false"
spec:
  schedule: "@every 5m"
  kubernetesResource:
    - name: ingress-accessibility-check
      namespace: default
      description: "deploy httpbin & check that it's accessible via ingress"
      waitFor: 
        expr: 'dyn(resources).all(r, k8s.isReady(r))'
        interval: 2s
        timeout: 5m
      staticResources:
        - apiVersion: networking.k8s.io/v1
          kind: Ingress
          metadata:
            name: httpbin
            namespace: default
          spec:
            rules:
              - host: "httpbin.127.0.0.1.nip.io"
                http:
                  paths:
                    - pathType: Prefix
                      path: /
                      backend:
                        service:
                          name: httpbin
                          port:
                            number: 80
      resources:
        - apiVersion: v1
          kind: Pod
          metadata:
            name: httpbin
            namespace: default
            labels:
              app: httpbin
          spec:
            containers:
              - name: httpbin
                image: "kennethreitz/httpbin:latest"
                ports:
                  - containerPort: 80
        - apiVersion: v1
          kind: Service
          metadata:
            name: httpbin
            namespace: default
          spec:
            selector:
              app: httpbin
            ports:
              - port: 80
                targetPort: 80
      checks:
        - http:
            - name: Call httpbin via ingress
              url: "http://ingress-nginx.ingress-nginx.svc"
              headers:
                - name: Host
                  value: "{{(index ((index .staticResources 0).Object.spec.rules) 0).host}}"
      checkRetries:
        delay: 3s
        interval: 2s
        timeout: 5m

Field	Description	Scheme
name*	Name of the check, must be unique within the canary	string
resources*	Manifests that should be applied	[]KubernetesManifest
checkRetries	Retry configuration for the checks	CheckRetries
checks	canary spec for the checks to be performed after the resources are created	CanarySpec
clearResources	When set to true, resources from previous checks are deleted before every run. Even though the resources are deleted at the end of a check, setting this to true guarantees that there are no leftover resources from a previous failed run.	boolean
staticResources	Static resources are like resources but preserved between checks. They are only deleted when the canary is deleted.	[]KubernetesManifest
waitFor	Specify the desired state of the static/non-static resources before running the checks	WaitFor
description	Description for the check	string
display	Expression to change the formatting of the display	Expression
icon	Icon for overwriting default icon on the dashboard	Icon
labels	Labels for check	map[string]string
metrics	Metrics to export from	[]Metrics
test	Evaluate whether a check is healthy	Expression
transform	Transform data from a check into multiple individual checks	Expression
kubeconfig	Path to a kubeconfig on disk, or a reference to an existing secret	EnvVar

Check Retries

Field	Description	Scheme
delay	Initial delay before the checks are run	Duration
interval	Retry the checks, on failure, on this interval	Duration
timeout	Timeout for the check	Duration

Wait For

Field	Description	Scheme
delete	When set to true, the check waits for the resources to be deleted	boolean
disable	Disable the default behavior of waiting for resources to be healthy.	Duration
expr	CEL expression that determines whether all the resources are in their desired state before running checks on them. It receives a resources array of the static and non-static resources. The default behavior is to wait until all the resources are ready dyn(resources).all(r, k8s.isReady(r)).	CEL
interval	Interval to check if all static & non-static resources are ready. (Default: 5s)	Duration
timeout	Timeout to wait for all static & non-static resources to satisfy the expression. (Default: 10m)	Duration

Templating

The resources and staticResources fields can be templated using Go Templates. This is helpful in creating resources with random names. Example: you can setup a resource to create a pod with random name on each check run. This way you don't have to wait for the pod to be deleted on every check.

info

Templating the Group, Version, Kind & Namespace however isn't allowed.

Creating a pod with a unique name on every run

pod_exit_code_check.yaml
---
apiVersion: canaries.flanksource.com/v1
kind: Canary
metadata:
  name: pod-exit-code-check
  namespace: default
  labels:
    "Expected-Fail": "false"
spec:
  schedule: "@every 5m"
  kubernetesResource:
    - name: "pod exit code"
      description: "Create pod & check its exit code"
      namespace: default
      display:
        expr: |
          "Result of check 'exit-code-check': " + display["exit-code-check"]
      resources:
        - apiVersion: v1
          kind: Pod
          metadata:
            name: "hello-world-{{strings.ToLower (random.Alpha 10)}}"
            namespace: default
          spec:
            restartPolicy: Never
            containers:
              - name: hello-world
                image: hello-world
      waitFor:
        expr: "dyn(resources).all(r, k8s.isHealthy(r))"
        interval: "1s"
        timeout: "20s"
      checkRetries:
        delay: 2s
        timeout: 5m
      checks:
        - kubernetes:
            - name: exit-code-check
              kind: Pod
              namespaceSelector:
                name: default
              resource:
                name: "{{(index .resources 0).Object.metadata.name}}"
              test:
                expr: >
                  size(results) == 1 &&
                  results[0].Object.status.containerStatuses[0].state.terminated.exitCode == 0

Examples

Creating a namespace

namespace_creation.yaml
---
apiVersion: canaries.flanksource.com/v1
kind: Canary
metadata:
  name: namespace-creation 
  namespace: default
  labels:
    "Expected-Fail": "false"
spec:
  schedule: "@every 5m"
  kubernetesResource:
    - name: "namespace creation"
      namespace: "default"
      description: "create a namespace and pod in it"
      waitFor: 
        timeout: 3m
        delete: true
      staticResources:
        - apiVersion: v1
          kind: Namespace
          metadata:
            name: test
      resources:
        - apiVersion: v1
          kind: Pod
          metadata:
            name: httpbin
            namespace: test
            labels:
              app: httpbin
          spec:
            containers:
              - name: httpbin
                image: "kennethreitz/httpbin:latest"
                ports:
                  - containerPort: 80

warning

Since static resources are deleted when the canary is deleted, extra care must be taken when providing their manifests. When this canary is deleted, the test namespace is deleted and consequently all the other resources within it, even those not created by this check.

Crossplane Example

namespace_creation.yaml
apiVersion: canaries.flanksource.com/v1
kind: Canary
metadata:
  name: crossplane-kubernetes-resource
spec:
  schedule: "@every 10m"
  kubernetesResource:
    - name: crossplane-kubernetes-resource
      namespace: canaries
      description: "Create an S3 bucket via crossplane and run s3 check on it"
      waitFor: 
        expr: 'dyn(resources).all(r, has(r.Object.status.atProvider) && has(r.Object.status.atProvider.arn))'
        interval: 30s
        timeout: 5m
      resources:
        - apiVersion: s3.aws.crossplane.io/v1beta1
          kind: Bucket
          metadata:
            name: check-bucket
          spec:
            forProvider:
              acl: private
              locationConstraint: us-east-1
            providerConfigRef:
              name: localstack

      checks:
        - s3:
          - name: s3-check
            bucketName: "{{ (index .resources 0).Object.metadata.name }}"
            objectPath: dummy
            region: "{{ (index .resources 0).Object.spec.forProvider.locationConstraint }}"
            endpoint: http://localstack-localstack.localstack.svc.cluster.local:4566
            usePathStyle: true
            accessKey:
              value: test
            secretKey:
              value: test
      checkRetries:
        delay: 60s
        interval: 10s
        timeout: 5m