Running Istio Service Mesh on OpenShift

In the Kubernetes/OpenShift community everyone is talking about Istio service mesh, so I wanted to share my experience about the installation and running a sample microservice application with Istio on OpenShift 3.11 and 4.0. Service mesh on OpenShift is still at least a few month away from being available generally to run in production but this gives you the possibility to start testing and exploring Istio. I have found good documentation about installing Istio on OCP and OKD have a look for more information.

To install Istio on OpenShift 3.11 you need to apply the node and master prerequisites you see below; for OpenShift 4.0 and above you can skip these steps and go directly to the istio-operator installation:

sudo bash -c 'cat << EOF > /etc/origin/master/master-config.patch
admissionConfig:
  pluginConfig:
    MutatingAdmissionWebhook:
      configuration:
        apiVersion: apiserver.config.k8s.io/v1alpha1
        kubeConfigFile: /dev/null
        kind: WebhookAdmission
    ValidatingAdmissionWebhook:
      configuration:
        apiVersion: apiserver.config.k8s.io/v1alpha1
        kubeConfigFile: /dev/null
        kind: WebhookAdmission
EOF'
        
sudo cp -p /etc/origin/master/master-config.yaml /etc/origin/master/master-config.yaml.prepatch
sudo bash -c 'oc ex config patch /etc/origin/master/master-config.yaml.prepatch -p "$(cat /etc/origin/master/master-config.patch)" > /etc/origin/master/master-config.yaml'
sudo su -
master-restart api
master-restart controllers
exit       

sudo bash -c 'cat << EOF > /etc/sysctl.d/99-elasticsearch.conf 
vm.max_map_count = 262144
EOF'

sudo sysctl vm.max_map_count=262144

The Istio installation is straight forward by starting first to install the istio-operator:

oc new-project istio-operator
oc new-app -f https://raw.githubusercontent.com/Maistra/openshift-ansible/maistra-0.9/istio/istio_community_operator_template.yaml --param=OPENSHIFT_ISTIO_MASTER_PUBLIC_URL=<-master-public-hostname->

Verify the operator deployment:

oc logs -n istio-operator $(oc -n istio-operator get pods -l name=istio-operator --output=jsonpath={.items..metadata.name})

Once the operator is running we can start deploying Istio components by creating a custom resource:

cat << EOF >  ./istio-installation.yaml
apiVersion: "istio.openshift.com/v1alpha1"
kind: "Installation"
metadata:
  name: "istio-installation"
  namespace: istio-operator
EOF

oc create -n istio-operator -f ./istio-installation.yaml

Check and watch the Istio installation progress which might take a while to complete:

oc get pods -n istio-system -w

# The installation of the core components is finished when you see:
...
openshift-ansible-istio-installer-job-cnw72   0/1       Completed   0         4m

Afterwards, to finish off the Istio installation, we need to install the Kiali web console:

bash <(curl -L https://git.io/getLatestKialiOperator)
oc get route -n istio-system -l app=kiali

Verifying that all Istio components are running:

$ oc get pods -n istio-system
NAME                                          READY     STATUS      RESTARTS   AGE
elasticsearch-0                               1/1       Running     0          9m
grafana-74b5796d94-4ll5d                      1/1       Running     0          9m
istio-citadel-db879c7f8-kfxfk                 1/1       Running     0          11m
istio-egressgateway-6d78858d89-58lsd          1/1       Running     0          11m
istio-galley-6ff54d9586-8r7cl                 1/1       Running     0          11m
istio-ingressgateway-5dcf9fdf4b-4fjj5         1/1       Running     0          11m
istio-pilot-7ccf64f659-ghh7d                  2/2       Running     0          11m
istio-policy-6c86656499-v45zr                 2/2       Running     3          11m
istio-sidecar-injector-6f696b8495-8qqjt       1/1       Running     0          11m
istio-telemetry-686f78b66b-v7ljf              2/2       Running     3          11m
jaeger-agent-k4tpz                            1/1       Running     0          9m
jaeger-collector-64bc5678dd-wlknc             1/1       Running     0          9m
jaeger-query-776d4d754b-8z47d                 1/1       Running     0          9m
kiali-5fd946b855-7lw2h                        1/1       Running     0          2m
openshift-ansible-istio-installer-job-cnw72   0/1       Completed   0          13m
prometheus-75b849445c-l7rlr                   1/1       Running     0          11m

Let’s start to deploy the microservice application example by using the Google Hipster Shop, it contains multiple microservices which is great to test with Istio:

# Create new project
oc new-project hipster-shop

# Set permissions to allow Istio to deploy the Envoy-Proxy side-car container
oc adm policy add-scc-to-user anyuid -z default -n hipster-shop
oc adm policy add-scc-to-user privileged -z default -n hipster-shop

# Create Hipster Shop deployments and Istio services
oc create -f https://raw.githubusercontent.com/berndonline/openshift-ansible/master/examples/istio-hipster-shop.yml
oc create -f https://raw.githubusercontent.com/berndonline/openshift-ansible/master/examples/istio-manifest.yml

# Wait and check that all pods are running before creating the load generator
oc get pods -n hipster-shop -w

# Create load generator deployment
oc create -f https://raw.githubusercontent.com/berndonline/openshift-ansible/master/examples/istio-loadgenerator.yml

As you see below each pod has a sidecar container with the Istio Envoy proxy which handles pod traffic:

[[email protected]1-167 ~]$ oc get pods
NAME                                     READY     STATUS    RESTARTS   AGE
adservice-7894dbfd8c-g4m9v               2/2       Running   0          49m
cartservice-758d66c648-79fj4             2/2       Running   4          49m
checkoutservice-7b9dc8b755-h2b2v         2/2       Running   0          49m
currencyservice-7b5c5f48fc-gtm9x         2/2       Running   0          49m
emailservice-79578566bb-jvwbw            2/2       Running   0          49m
frontend-6497c5f748-5fc4f                2/2       Running   0          49m
loadgenerator-764c5547fc-sw6mg           2/2       Running   0          40m
paymentservice-6b989d657c-klp4d          2/2       Running   0          49m
productcatalogservice-5bfbf4c77c-cw676   2/2       Running   0          49m
recommendationservice-c947d84b5-svbk8    2/2       Running   0          49m
redis-cart-79d84748cf-cvg86              2/2       Running   0          49m
shippingservice-6ccb7d8ff7-66v8m         2/2       Running   0          49m
[[email protected] ~]$

The Kiali web console answers the question about what microservices are part of the service mesh and how are they connected which gives you a great level of detail about the traffic flows:

Detailed traffic flow view:

The Isito installation comes with Jaeger which is an open source tracing tool to monitor and troubleshoot transactions:

Enough about this, lets connect to our cool Hipster Shop and happy shopping:

Additionally there is another example, the Istio Bookinfo if you want to try something smaller and less complex:

oc new-project myproject

oc adm policy add-scc-to-user anyuid -z default -n myproject
oc adm policy add-scc-to-user privileged -z default -n myproject

oc apply -n myproject -f https://raw.githubusercontent.com/Maistra/bookinfo/master/bookinfo.yaml
oc apply -n myproject -f https://raw.githubusercontent.com/Maistra/bookinfo/master/bookinfo-gateway.yaml
export GATEWAY_URL=$(oc get route -n istio-system istio-ingressgateway -o jsonpath='{.spec.host}')
curl -o /dev/null -s -w "%{http_code}\n" http://$GATEWAY_URL/productpage

curl -o destination-rule-all.yaml https://raw.githubusercontent.com/istio/istio/release-1.0/samples/bookinfo/networking/destination-rule-all.yaml
oc apply -f destination-rule-all.yaml

curl -o destination-rule-all-mtls.yaml https://raw.githubusercontent.com/istio/istio/release-1.0/samples/bookinfo/networking/destination-rule-all-mtls.yaml
oc apply -f destination-rule-all-mtls.yaml

oc get destinationrules -o yaml

I hope this is a useful article for getting started with Istio service mesh on OpenShift.