Pod recreation due to container.name tag missing in the jaeger.tags argument

[lujiajing1126]

We have observed Pod recreation events in the production cluster very similar to this issue #1089

We find the following logs in the operator container,

...
time="2020-11-27T01:24:15Z" level=info msg="Injecting Jaeger Agent sidecar" deployment=hera-alertgateway-ack-deploy jaeger=jaeger-ack jaeger-namespace=observability namespace=sqb
time="2020-11-27T01:24:15Z" level=info msg="Injecting Jaeger Agent sidecar" deployment=kubernetes-ack-jack-ack-deploy jaeger=jaeger-ack jaeger-namespace=observability namespace=sqb
time="2020-11-27T01:24:15Z" level=info msg="Injecting Jaeger Agent sidecar" deployment=merchant-dmp-datacenter-ack-deploy jaeger=jaeger-ack jaeger-namespace=observability namespace=sqb
time="2020-11-27T01:24:15Z" level=info msg="Injecting Jaeger Agent sidecar" deployment=merchant-dmp-service-ack-deploy jaeger=jaeger-ack jaeger-namespace=observability namespace=sqb

These are the four deployments annotated with sidecar.jaegertracing.io/inject: 'true', and these event repeatedly occur recently. In the meantime, we find the following events from kubernetes, the times exactly coincide.

Thus, we compared two replicaSets generated and found the arguments of two agent containers are different,

$ diff merchant-dmp-datacenter-ack-deploy-6d5dc79477 merchant-dmp-datacenter-ack-deploy-68b5cc4bd6
...(not related)
120c120
<         - --jaeger.tags=cluster=undefined,deployment.name=merchant-dmp-datacenter-ack-deploy,pod.namespace=sqb,pod.name=${POD_NAME:},host.ip=${HOST_IP:},container.name=merchant-dmp-datacenter-ack
---
>         - --jaeger.tags=cluster=undefined,deployment.name=merchant-dmp-datacenter-ack-deploy,pod.namespace=sqb,pod.name=${POD_NAME:},host.ip=${HOST_IP:}

I suppose it is related to

jaeger-operator/pkg/inject/sidecar.go

Lines 198 to 202 in f250749

	if len(dep.Spec.Template.Spec.Containers) == 1 {
	agentTags = fmt.Sprintf("%s,%s=%s", agentTags,
	"container.name", dep.Spec.Template.Spec.Containers[0].Name,
	)
	}

since the agent container has already been injected.

[jpkrohling]

Thank you for finding the root cause and for the PR!