# Introduction to Istio ## We need a Kubernetes cluster Lets create a Kubernetes cluster to play with using [kind](https://kind.sigs.k8s.io/docs/user/quick-start/) ``` kind create cluster --name istio --image kindest/node:v1.19.1 ``` ## Deploy our microservices (Video catalog) ``` # ingress controller kubectl create ns ingress-nginx kubectl apply -f kubernetes/servicemesh/applications/ingress-nginx/ # applications kubectl apply -f kubernetes/servicemesh/applications/playlists-api/ kubectl apply -f kubernetes/servicemesh/applications/playlists-db/ kubectl apply -f kubernetes/servicemesh/applications/videos-api/ kubectl apply -f kubernetes/servicemesh/applications/videos-web/ kubectl apply -f kubernetes/servicemesh/applications/videos-db/ ``` ## Make sure our applications are running ``` kubectl get pods NAME READY STATUS RESTARTS AGE playlists-api-d7f64c9c6-rfhdg 1/1 Running 0 2m19s playlists-db-67d75dc7f4-p8wk5 1/1 Running 0 2m19s videos-api-7769dfc56b-fsqsr 1/1 Running 0 2m18s videos-db-74576d7c7d-5ljdh 1/1 Running 0 2m18s videos-web-598c76f8f-chhgm 1/1 Running 0 100s ``` ## Make sure our ingress controller is running ``` kubectl -n ingress-nginx get pods NAME READY STATUS RESTARTS AGE nginx-ingress-controller-6fbb446cff-8fwxz 1/1 Running 0 2m38s nginx-ingress-controller-6fbb446cff-zbw7x 1/1 Running 0 2m38s ``` We'll need a fake DNS name `servicemesh.demo`
Let's fake one by adding the following entry in our hosts (`C:\Windows\System32\drivers\etc\hosts`) file:
``` 127.0.0.1 servicemesh.demo ``` ## Let's access our applications via Ingress ``` kubectl -n ingress-nginx port-forward deploy/nginx-ingress-controller 80 ``` ## Access our application in the browser We should be able to access our site under `http://servicemesh.demo/home/`
# Getting Started with Istio Firstly, I like to do most of my work in containers so everything is reproducable
and my machine remains clean. ## Get a container to work in
Run a small `alpine linux` container where we can install and play with `istio`:
``` docker run -it --rm -v ${HOME}:/root/ -v ${PWD}:/work -w /work --net host alpine sh # install curl & kubectl apk add --no-cache curl nano curl -LO https://storage.googleapis.com/kubernetes-release/release/`curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt`/bin/linux/amd64/kubectl chmod +x ./kubectl mv ./kubectl /usr/local/bin/kubectl export KUBE_EDITOR="nano" #test cluster access: /work # kubectl get nodes NAME STATUS ROLES AGE VERSION istio-control-plane Ready master 26m v1.18.4 ``` ## Install Istio CLI ``` curl -L https://istio.io/downloadIstio | ISTIO_VERSION=1.6.12 TARGET_ARCH=x86_64 sh - mv istio-1.6.12/bin/istioctl /usr/local/bin/ chmod +x /usr/local/bin/istioctl mv istio-1.6.12 /tmp/ ``` ## Pre flight checks Istio has a great capability to check compatibility with the target cluster
``` istioctl x precheck ``` ## Istio Profiles https://istio.io/latest/docs/setup/additional-setup/config-profiles/ ``` istioctl profile list istioctl install --set profile=default kubectl -n istio-system get pods istioctl proxy-status ``` # Mesh our video catalog services There are 2 ways to mesh: 1) Automated Injection: You can set the `istio-injection=enabled` label on a namespace to have the istio side car automatically injected into any pod that gets created in the labelled namespace This is a more permanent solution: Pods will need to be recreated for injection to occur ``` kubectl label namespace/default istio-injection=enabled ``` 2) Manual Injection: This may only be temporary as your CI/CD system may roll out the previous YAML. You may want to add this command to your CI/CD to keep only certain deployments part of the mesh. ``` kubectl get deploy NAME READY UP-TO-DATE AVAILABLE AGE playlists-api 1/1 1 1 8h playlists-db 1/1 1 1 8h videos-api 1/1 1 1 8h videos-db 1/1 1 1 8h videos-web 1/1 1 1 8h # You can manually inject istio sidecar to every deployment like this: kubectl get deploy playlists-api -o yaml | istioctl kube-inject -f - | kubectl apply -f - kubectl get deploy playlists-db -o yaml | istioctl kube-inject -f - | kubectl apply -f - kubectl get deploy videos-api -o yaml | istioctl kube-inject -f - | kubectl apply -f - kubectl get deploy videos-db -o yaml | istioctl kube-inject -f - | kubectl apply -f - kubectl get deploy videos-web -o yaml | istioctl kube-inject -f - | kubectl apply -f - kubectl -n ingress-nginx get deploy nginx-ingress-controller -o yaml | istioctl kube-inject -f - | kubectl apply -f - ``` # TCP \ HTTP traffic Let's run a `curl` loop to generate some traffic to our site
We'll make a call to `/home/` and to simulate the browser making a call to get the playlists,
we'll make a follow up call to `/api/playlists` ``` While ($true) { curl -UseBasicParsing http://servicemesh.demo/home/;curl -UseBasicParsing http://servicemesh.demo/api/playlists; Start-Sleep -Seconds 1;} ``` # Observability ## Prometheus ``` kubectl apply -f /tmp/istio-1.6.12/samples/addons/prometheus.yaml ``` ## Grafana ``` kubectl apply -n istio-system -f /tmp/istio-1.6.12/samples/addons/grafana.yaml ``` We can see the components in the `istio-system` namespace: ``` kubectl -n istio-system get pods ``` Access grafana dashboards : ``` kubectl -n istio-system port-forward svc/grafana 3000 ``` ## Kiali `NOTE: this may fail because CRDs need to generate, if so, just rerun the command:` ``` kubectl apply -f /tmp/istio-1.6.12/samples/addons/kiali.yaml kubectl -n istio-system get pods kubectl -n istio-system port-forward svc/kiali 20001 ``` # Virtual Services ## Auto Retry Let's add a fault in the `videos-api` by setting `env` variable `FLAKY=true` ``` kubectl edit deploy videos-api ``` ``` kubectl apply -f kubernetes/servicemesh/istio/retries/videos-api.yaml ``` We can describe pods using `istioctl` ``` # istioctl x describe pod istioctl x describe pod videos-api-584768f497-jjrqd Pod: videos-api-584768f497-jjrqd Pod Ports: 10010 (videos-api), 15090 (istio-proxy) Suggestion: add 'version' label to pod for Istio telemetry. -------------------- Service: videos-api Port: http 10010/HTTP targets pod port 10010 VirtualService: videos-api 1 HTTP route(s) ``` Analyse our namespace: ``` istioctl analyze --namespace default ``` ## Traffic Splits Let's deploy V2 of our application which has a header that's under development ``` kubectl apply -f kubernetes/servicemesh/istio/traffic-splits/videos-web-v2.yaml # we can see v2 pods kubectl get pods ``` Let's send 50% of traffic to V1 and 50% to V2 by using a `VirtualService` ``` kubectl apply -f kubernetes/servicemesh/istio/traffic-splits/videos-web.yaml ``` ## Canary Deployments Traffic splits has its uses, but sometimes we may want to route traffic to other
parts of the system using feature toggles, for example, setting a `cookie`

Let's send all users that have the cookie value `version=v2` to V2 of our `videos-web`. ``` kubectl apply -f kubernetes/servicemesh/istio/canary/videos-web.yaml ``` We can confirm this works, by setting the cookie value `version=v2` followed by accessing https://servicemesh.demo/home/ on an incogneto browser page