Get started with Istio - trim log while retrying


After this section we could add a `| tail -6` 
> `If you check the logs of the purchase-history service, you will see the retries:`

```bash
kubectl logs deploy/purchase-history-v3 -n istioinaction | grep x-envoy-attempt-count | tail -6
```
in case someone retires many times, if we don't tail the log, the number of log lines become very long