You need Event Mesh, not Service Mesh - Chris Suszynski [WJUG 301]
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The document discusses the need for an event mesh instead of a service mesh, emphasizing the pitfalls of relying on transactions and the fallacy of service meshes for remote service calls. It presents the concepts of eventual consistency, command and query responsibility segregation (CQRS), and Kubernetes' reconciliation loop, along with an introduction to event mesh as a flexible infrastructure for event distribution. The content also includes information about Knative, an extension for managing serverless applications on Kubernetes.
![Extension
// MemcachedSpec defines the desired state of Memcached
type MemcachedSpec struct {
//+kubebuilder:validation:Minimum=0
// Size is the size of the memcached deployment
Size int32 `json:"size"`
}
// MemcachedStatus defines the observed state of Memcached
type MemcachedStatus struct {
// Nodes are the names of the memcached pods
Nodes []string `json:"nodes"`
}](https://image.slidesharecdn.com/youneedeventmeshnotservicemesh-chrissuszynskiwjug301-230509175217-70869afa/85/You-need-Event-Mesh-not-Service-Mesh-Chris-Suszynski-WJUG-301-12-320.jpg)
You need Event Mesh, not Service Mesh - Chris Suszynski [WJUG 301]
- 1. Public Version 1.0 You need Event Mesh, not Service Mesh! Chris Suszyński @ksuszynski +krzysztof-suszynski
- 2. About me 2 Chris Suszyński ➔ Senior Software Engineer at Red Hat ➔ Work on OpenShift Serverless ➔ Go, Rust and Java enthusiast ➔ 15+ years of experience ➔ FOSS contributor: ~80 original repos ➔ Happy father and husband
- 3. Public Version 1.0 Agenda ➔ Transactional lie ➔ Eventual consistency ➔ Service Mesh fallacy ➔ CQRS ➔ Kubernetes reconcile loop ➔ Event Mesh ➔ Knative ➔ Demos, show me the code!
- 4. Transactional - a lie, trap 1 Transactional are rare 2 We overuse it massively 3 Distorts the business logic 4 Slow and error-prone
- 7. Try 1 Naive split into remote μ-Svc ➔ 12 remote calls to 5 remote μ-Svc! ➔ 99.99% uptime ^ 12 = 99.88% ➔ 1000% slower ➔ Possible data loss
- 8. Service Mesh fallacy The Service Mesh promises a safe layer for remote service calls. But, we shouldn’t do synchronous, remote calls apart from queries!
- 9. CQRS CQRS stands for Command and Query Responsibility Segregation, a pattern that separates read and update operations for a data store. Changes Command ➔ Asynchronous ➔ aka Events ➔ Do not lose it Read Query ➔ Synchronous ➔ Request, Response ➔ Safe to retry
- 10. CQRS example Dividing the example into Command and Queries Commands / Events ➔ CompleteTransit ➔ UpdateDestination ➔ CalculateFee ➔ DriverFree ➔ RegisterMiles ➔ IssueInvoice Queries ➔ ReadTransit ➔ ReadAddress ➔ …
- 12. Extension // MemcachedSpec defines the desired state of Memcached type MemcachedSpec struct { //+kubebuilder:validation:Minimum=0 // Size is the size of the memcached deployment Size int32 `json:"size"` } // MemcachedStatus defines the observed state of Memcached type MemcachedStatus struct { // Nodes are the names of the memcached pods Nodes []string `json:"nodes"` }
- 13. Reconcile loop import ( ctrl "sigs.k8s.io/controller-runtime" cachev1alpha1 "github.com/example/memcached-operator/api/v1alpha1" ... ) func (r *MemcachedReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) { // Lookup the Memcached instance for this reconcile request memcached := &cachev1alpha1.Memcached{} err := r.Get(ctx, req.NamespacedName, memcached) ... }
- 14. Demo
- 15. Watch out! Kubernetes' reconciliation loop relies on ETCD watch feature. It works until a point, ~100k records.
- 16. Event Mesh
- 17. What is the Event Mesh? “An event mesh is a configurable and dynamic infrastructure layer for distributing events among decoupled applications, cloud services and devices. It enables event communications to be governed, flexible, reliable and fast.”
- 18. Event Mesh vs Service Mesh Service Mesh Event Mesh Similarities ➔ Flexibility ➔ Robustness ➔ Decoupling Differences ➔ Synchronous ➔ Request and response ➔ Better for queries ➔ Asynchronous ➔ Event ➔ Better for commands
- 19. based on Knative OpenShift Serverless
- 20. is a Kubernetes extension that allows you to deploy and manage modern serverless apps. Knative
- 21. 21 Knative in OpenShift ➔ Knative is a CNCF Open Source project ➔ A community driven by multiple stakeholders https://knative.dev ◆ Supported by Google, Red Hat, IBM, VMware, TriggerMesh, SAP and more ➔ OpenShift Serverless: https://www.openshift.com/learn/topics/serverless ➔ Latest production-ready release: 1.28.0 (Knative 1.7)
- 22. Demo
- 24. Resources ● github.com / wavesoftware / passless-operator ● github.com / cardil / cabs-usvc ● developers.redhat.com ● bit.ly/knative-tutorial