ControllerMesh is a solution that helps developers manage their controllers/operators better.
- Canary update: the controllers can be updated in canary progress instead of one time replace.
- Fault injection: it helps developers to verify their reconcile logic in some fault scenarios.
- Flexible isolation: limits resources of which namespaces can be queried by a controller.
- Client-side rate-limit and blown.
ctrlmesh-proxy container will be injected into each operator Pod that has configured in ControllerMesh. This proxy container will intercept and handle the connection by between API Server and controllers/webhooks in the Pod.
ctrlmesh-manager dispatches rules to the proxies, so that they can route requests according to the rules.
A core CRD in ControllerMesh is
VirtualApp. It contains all rules for user’s controller and webhook:
apiVersion: ctrlmesh.kruise.io/v1alpha1 kind: VirtualApp metadata: name: test-operator # ... spec: selector: matchLabels: component: test-operator configuration: controller: leaderElectionName: test-operator webhook: certDir: /tmp/webhook-certs port: 9443 route: globalLimits: - namespaceSelector: matchExpressions: - key: ns-type operator: NotIn values: - system subRules: - name: canary-rule match: - namespaceSelector: matchLabels: ns-type: canary-1 - namespaceRegex: "^canary.*" subsets: - name: v2 labels: version: v2 routeRules: - canary-rule
- selector: for all pods of the test-operator
- controller: configuration for controller, including leader election name
- webhook: configuration for webhook, including certDir and port of this webhook
- globalLimits: limit rules that enable to all pods of test-operator
- subRules: multiple rules that can define to be used in subsets
- subsets: multiple groups of the pods, each subset has specific labels and its route rules
ControllerMesh will firstly support Hard Limit type of flow control, which means the ctrlmesh-proxy will filter unmatched requests/responses between API Server and local controller/webhook.
Risks and Mitigations
- The controller/webhook can not get any requests if ctrlmesh-proxy container crashes.
- Developers can not change the flow rules of their operators if kruise-manager is not working.
- The performance of controller/webhook will be a little worse.
- Pod of the operator requires a few more resources because of a ctrlmesh-proxy container injected into it.
ControllerMesh is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.