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+# Istio
+
+Istio provides an alternative way to control ingress traffic into the cluster.
+In addition, it allows to finetune the traffic inside the cluster and provides
+a huge repertoire of load balancing and routing mechanisms.
+
+***note
+Currently, only the Gerrit replica chart allows using istio out of the box.
+***
+
+## Install istio
+
+An example configuration based on the default profile provided by istio can be
+found under `./istio/src/`. Some values will have to be adapted to the respective
+system. These are marked by comments tagged with `TO_BE_CHANGED`.
+To install istio with this configuration, run:
+
+```sh
+kubectl apply -f istio/istio-system-namespace.yaml
+istioctl install -f istio/gerrit.profile.yaml
+```
+
+To install Gerrit using istio for networking, the namespace running Gerrit has to
+be configured to enable sidecar injection, by setting the `istio-injection: enabled`
+label. An example for such a namespace can be found at `./istio/namespace.yaml`.
+
+## Uninstall istio
+
+To uninstall istio, run:
+
+```sh
+istioctl uninstall -f istio/gerrit.profile.yaml
+```
+
+## Restricting access to a list of allowed IPs
+
+In development setups, it might be wanted to allow access to the setup only from
+specified IPs. This can be done by patching the `spec.loadBalancerSourceRanges`
+value of the service used for the IngressGateway. A patch doing that can be
+uncommented in `istio/gerrit.profile.yaml`.