Deconfigure istio proxy tracer explicit to avoid DNS lookups #17811
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skhalash
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Description
Debugging a kyma cluster using tcpdump on a privileged pod reveals that constantly DNS lookups for
zipkin.istio-systemare performed. Analyzing the configuration further revealed that the extensionProvider configuration mechanism seems to enable the zipkin tracer additionally to the configured providers. An upstream ticket got created for now istio/istio#45890, we still need to see if we can contribute a fix.As the main problem is the additional stress to CoreDNS with negative DNS lookups, this PR disabled explicitly the tracer in the proxy config as described as a workaround in the upstream bug report.
To validate that the change will not cause any additional DNS entries, deploy a privileged pod (for example using the Gardener terminal) and execute
tcpdump -i any -vvv -s0 -w capture.pcap.Then copy the captured file using
and analyze the file using wireshark. Enter "dns" as the filter criteria.
Changes proposed in this pull request:
Related issue(s)
istio/istio#45890