Step 3: Upgrade Istio to 1.9

common/istio-1-9-0/README.md

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+# Istio
+
+## Upgrade Istio Manifests
+
+Istio ships with an installer called `istioctl`, which is a deployment /
+debugging / configuration management tool for Istio all in one package.
+In this section, we explain how to upgrade our istio kustomize packages
+by leveraging `istioctl`. Assuming the new version is `X.Y.Z` and the
+old version is `X1.Y1.Z1`:
+
+1.  Make a copy of the old istio manifests tree, which will become the
+    kustomization for the new Istio version:
+
+        $ export MANIFESTS_SRC=<path/to/manifests/repo>
+        $ export ISTIO_OLD=$MANIFESTS_SRC/common/istio-X1-Y1-Z1
+        $ export ISTIO_NEW=$MANIFESTS_SRC/common/istio-X-Y-Z
+        $ cp -a $ISTIO_OLD $ISTIO_NEW
+
+2.  Download `istioctl` for version `X.Y.Z`:
+
+        $ ISTIO_VERSION="X.Y.Z"
+        $ wget "https://github.com/istio/istio/releases/download/${ISTIO_VERSION}/istio-${ISTIO_VERSION}-linux.tar.gz"
+        $ tar xvfz istio-${ISTIO_VERSION}-linux.tar.gz
+        # sudo mv istio-${ISTIO_VERSION}/bin/istioctl /usr/local/bin/istioctl
+
+3.  Use `istioctl` to generate an `IstioOperator` resource, the
+    CustomResource used to describe the Istio Control Plane:
+
+        $ istioctl profile dump demo > profile.yaml
+
+    ---
+    **NOTE**
+
+    `istioctl` comes with a bunch of [predefined
+    profiles](https://istio.io/v1.9/docs/setup/additional-setup/config-profiles/)
+    (`default`, `demo`, `minimal`, etc.). The `demo` profile enables
+    high levels of tracing and access logging and included monitoring
+    components in the past, which we wanted to install. In the future,
+    we can consider moving to the `default` profile.
+
+    ---
+
+4.  Generate manifests and add them to their respective packages. We
+    will generate manifests using `istioctl`, the
+    `profile.yaml` file from upstream and the
+    `profile-overlay.yaml` file that contains our desired
+    changes:
+
+        $ export PATH="$MANIFESTS_SRC/scripts:$PATH"
+        $ cd $ISTIO_NEW
+        $ istioctl manifest generate -f profile.yaml -f profile-overlay.yaml > dump.yaml
+        $ split-istio-packages -f dump.yaml
+        $ mv $ISTIO_NEW/crd.yaml $ISTIO_NEW/istio-crds/base
+        $ mv $ISTIO_NEW/install.yaml $ISTIO_NEW/istio-install/base
+        $ mv $ISTIO_NEW/cluster-local-gateway.yaml $ISTIO_NEW/cluster-local-gateway/base
+
+    ---
+    **NOTE**
+
+    `split-istio-packages` is a python script under `scripts/` that is
+    included in `PATH` in a bootstrapped env.
+
+    ---
+
+## Changes to Istio's upstream manifests
+
+### Changes to the upstream IstioOperator profile
+
+Changes to Istio's upstream profile `demo` are the following:
+
+-   Add a `cluster-local-gateway` component for KFServing.
+-   Disable the EgressGateway component. We don\'t use it and it adds
+    unnecessary complexity.
+
+Those changes are captured in the [profile-overlay.yaml](profile-overlay.yaml)
+file.
+
+### Changes to the upstream manifests using kustomize
+
+The Istio kustomizations make the following changes:
+
+- Remove PodDisruptionBudget from `istio-install` and `cluster-local-gateway` kustomizations. See:
+    - https://github.com/istio/istio/issues/12602
+    - https://github.com/istio/istio/issues/24000
+- Add EnvoyFilter for adding an `X-Forwarded-For` header in requests passing through the Istio Ingressgateway, inside the `istio-install` kustomization.
+- Add Istio AuthorizationPolicy to allow all requests to the Istio Ingressgateway and the Istio cluster-local gateway.
+- Add Istio AuthorizationPolicy in Istio's root namespace, so that sidecars deny traffic by default (explicit deny-by-default authorization model).
+- Add Gateway CRs for the Istio Ingressgateway and the Istio cluster-local gateway, as `istioctl` stopped generating them in later versions.
+- Add the istio-system namespace object to `istio-namespace`, as `istioctl` stopped generating it in later versions.