Main Glossary Jaeger

Jaeger

Jaeger

Why Jaeger?

As on-the-ground microservice practitioners are quickly realizing, the majority of operational problems that arise when moving to a distributed architecture are ultimately grounded in two areas: networking and observability. It is simply an orders of magnitude larger problem to network and debug a set of intertwined distributed services versus a single monolithic application.

Understanding Operators

The Jaeger Operator is an implementation of a Kubernetes Operator. Operators are pieces of software that ease the operational complexity of running another piece of software. More technically, Operators are a method of packaging, deploying, and managing a Kubernetes application.

A Kubernetes application is an application that is both deployed on Kubernetes and managed using the Kubernetes APIs and kubectl (kubernetes) or oc (OKD) tooling. To be able to make the most of Kubernetes, you need a set of cohesive APIs to extend in order to service and manage your apps that run on Kubernetes. Think of Operators as the runtime that manages this type of app on Kubernetes. Installing the Operator

The Jaeger Operator can be installed in Kubernetes-based clusters and is able to watch for new Jaeger custom resources (CR) in specific namespaces, or across the entire cluster. There is typically only one Jaeger Operator per cluster, but there might be at most one Jaeger Operator per namespace in multi-tenant scenarios. When a new Jaeger CR is detected, an operator will attempt to set itself as the owner of the resource, setting a label jaegertracing.io/operated-by to the new CR, with the operator’s namespace and name as the label’s value.

While multiple operators might coexist watching the same set of namespaces, which operator will succeed in setting itself as the owner of the CR is undefined behavior. Automatic injection of the sidecars might also result in undefined behavior. Therefore, it’s highly recommended to have at most one operator watching each namespace. Note that namespaces might contain any number of Jaeger instances (CRs).

The Jaeger Operator version tracks one version of the Jaeger components (Query, Collector, Agent). When a new version of the Jaeger components is released, a new version of the operator will be released that understands how running instances of the previous version can be upgraded to the new version.

Install modes

The Jaeger Operator can be installed to watch for new Jaeger custom resources (CRs) either in the whole cluster or in specific namespaces. When configured for cluster-mode, the operator can:

  • watch for events related to Jaeger resources in all namespaces
  • watch the namespaces themselves looking for the sidecar.jaegertracing.io/inject annotation
  • watch all deployments, to inject or remove sidecars based on the sidecar.jaegertracing.io/inject annotation
  • create cluster role bindings, when necessary

When not using the cluster-wide resources (ClusterRole and ClusterRoleBinding), set the WATCH_NAMESPACE to the comma-separated list of namespaces that the Jaeger Operator should watch for events related to Jaeger resources. It is possible to have the Jaeger Operator running in a given namespace (like, observability) and manage Jaeger resources in another (like, myproject). For that, use a RoleBinding like the following for each namespace the operator should watch for resources:

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: jaeger-operator-in-myproject
  namespace: myproject
subjects:
- kind: ServiceAccount
  name: jaeger-operator
  namespace: observability
roleRef:
  kind: Role
  name: jaeger-operator
  apiGroup: rbac.authorization.k8s.io

official jaegertracing.io