CNI logging works by sending logs over a UDS socket from the istio-cni binary up to the user-space install-cni container. There are a few issues here around logging levels and scopes.

• istio/cni/pkg/plugin/plugin.go

  Line 177 in 764e668

  log.FindScope("default").SetOutputLevel(getLogLevel(conf.LogLevel))

  sets the scope as configured by logLevel in the configmap, which is Values.cni.logLevel. This only handles default scope. if we have other scopes, we cannot configure them. Either we should apply this to all scopes, or allow the standard parsing of scopes that log_output_level does
• Daemonset doesn't allow setting the level at all:

  istio/manifests/charts/istio-cni/templates/daemonset.yaml

  Line 76 in ff3ccd1

  command: ["install-cni"]

• Maybe not a bug, but something we should consider:

  istio/cni/pkg/log/uds.go

  Line 121 in bf2adb0

  pluginLog.Debug(m.Msg)

  loses the original scope of the log. If we send scoped logs, we lose that info. Either we can lookup the original scope, or we should add a key to do the equivalent