Support env replacement in config-tracing

[ajp-lsq]

Problem I'm trying to run the opentelemetry-collector as an agent i.e. daemonset. For this to be maximally useful, I have to point each pod to the zipkin port 9411 on the pod's node's IP. Usually, you could do $(HOST_IP) replacement but it seems that the tracing config isn't applied uniformly: some pods load it as K_TRACING_CONFIG env, some pull it from the configmap directly. Either way, the $(HOST_IP) string is interpreted literally, not replaced.

Persona: Which persona is this feature for? System Operator

Exit Criteria A measurable (binary) test that would indicate that the problem has been resolved. When putting $(HOST_IP) in the zipkin-endpoint config value, it uses that env for replacement.

Time Estimate (optional): How many developer-days do you think this may take to resolve? No idea, it could be spread across a lot of codebase.

Additional context (optional) Add any other context about the feature request here.

[github-actions[bot]]

This issue is stale because it has been open for 90 days with no activity. It will automatically close after 30 more days of inactivity. Reopen the issue with /reopen. Mark the issue as fresh by adding the comment /remove-lifecycle stale.

[aslom]

/reopen

[knative-prow[bot]]

@aslom: Reopened this issue.

In response to this:

/reopen

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[github-actions[bot]]

This issue is stale because it has been open for 90 days with no activity. It will automatically close after 30 more days of inactivity. Reopen the issue with /reopen. Mark the issue as fresh by adding the comment /remove-lifecycle stale.