What is sidecar in Istio?

Related questions

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4. Is envoy a service mesh?
5. Why do we need Istio?
6. What is Istio Auth?
7. How does Istio sidecar work?
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9. What does Microservices mean?
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Tags

1. #pattern
2. #between
3. #without
4. #functionality
5. #enhanced
6. #sidecar
7. #extended
8. #strong
9. #particularly
10. #platform
11. #application
12. #containers
13. #orchestration
14. #kubernetes
15. #container
16. #composed
17. #using
18. #coupling
19. #useful