Copyright (c) 2012 Alex Ogier. All rights reserved.
Copyright (c) 2012 The Go Authors. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

   * Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
   * Redistributions in binary form must reproduce the above

Changes:
- separate namespace allows:
-- easier reconfig of just the gateway
-- TLS secrets and domain name management is isolated, for better security
-- simplified configuration
-- multiple versions of the ingress can be used, to minize upgrade risks

- the new chart uses the default namespace service account, and doesn't require
additional RBAC permissions.

- simplified label structure. Label change is not supported on upgrade.

Changes:
- separate namespace allows:
-- easier reconfig of just the gateway
-- TLS secrets and domain name management is isolated, for better security
-- simplified configuration
-- multiple versions of the ingress can be used, to minimize upgrade risks

- the new chart uses the default namespace service account, and doesn't require
additional RBAC permissions.

- simplified label and chart structure.

Unfortunately, writing controllers is very error prone, even for seemingly simple cases.
To work around this, Istio has a variety of abstractions meant to make writing controllers easier.

## Clients

Istio offers a variety of increasingly high level abstractions on top of the common Kubernetes [`client-go`](https://github.com/kubernetes/client-go).

```mermaid
flowchart TD