How to get Istio traceability with Grafana Tempo and Grafana Loki

Antonio Berben | September 01, 2021

(This content was originally published on the Grafana blog.)

“How am I supposed to debug this?”

Just imagine: Late Friday, you are about to shut down your laptop and an issue comes up. Warnings, alerts, red colors. Everything that we, developers, hate the most. The architect decided to develop that system based on microservices. Hundreds of them! You, as a developer, think… why? Why does the architect hate me so much? And then, the sentence: “How am I supposed to debug this?” Of course, we all understand the benefits of a microservice architecture. But we also hate the downsides. One of those is the process of debugging or running a postmortem analysis across hundreds of services. It is tedious and frustrating. Here is an example:

“Where do I start?,” you think. And you select the obvious candidate to start with the analysis: app1. And you read the logs shrinking by time period:

kubectl logs -l app=app1 --since=3h […]

“Nothing. Everything looks normal,” you say. “Maybe, the problem came from this other related service.” And again:

kubectl logs -l app=app2 --since=3h […]

“Aha! I see something weird here. This app2 has run a request to this other application, app3. Let’s see.” And yet again:

kubectl logs -l app=app3 --since=3h […]

Debugging takes ages. There is a lot of frustration until, finally, one manages to figure things out. As you can see, the process is slow. Quite inefficient. Time ago, we did not have logging and traceability in place. Today, the story can be different. Having Grafana Loki, Grafana Tempo and other small tools, we can debug things almost instantly.

Traceability: the feature you need

In order to be able to debug quickly, you need to mark the request with a unique ID. The mark is called Trace ID. And all the elements involved in the request, add another unique ID called span. At the end of the road, you are able to filter out the exact set of traces involved in the request which produced the issue.

Grafana traceability
And not only that. You can also draw all this in a visualization to easily understand the pieces which compose your system.

Grafana observability

How to do this with the Grafana stack

You are going to do a task simulating a microservices system with a service mesh: Istio. You will say: “Istio offers observability through Kiali.” For observability, Istio relies on Kiali. However, in the world of microservices, we should always show that there are alternatives that could fit the requirements, at least as good as the default ones.

Tempo and Loki are good examples of well-done logging and tracing backends. Regardless the performance comparisons, good points to consider are following ones:

Tempo and Loki, both, integrate with S3 buckets to store the data. This relieves you from maintaining and indexing storage that, depending on your requirements, might not be needed.
Tempo and Loki are part of grafana. Therefore, it integrates seamlessly with Grafana dashboards. (Well, being honest here: We all love and use grafana dashboards)

Now, let’s see how you can speed up the debugging process with Istio and the Grafana stack.

This will be your architecture:

Grafana Istio architecture

Hands on!

Pre-requisites

Kuberentes cluster
Istioctl. The task was developed with v.1.10 (https://github.com/istio/istio/releases)
Helm (https://helm.sh/)

Prepare Istio

You need to have Istio up and running. Let’s install the istio operator:

istioctl operator init

Now, let’s instantiate the service mesh. Istio proxies include a traceID in the `x-b3-traceid`. Notice that you will set the access logs to inject that trace ID as part of the log message:

kubectl apply -f - << 'EOF'
apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
metadata:
 name: istio-operator
 namespace: istio-system
spec:
 profile: default
 meshConfig:
   accessLogFile: /dev/stdout
   accessLogFormat: |
     [%START_TIME%] "%REQ(:METHOD)% %REQ(X-ENVOY-ORIGINAL-PATH?:PATH)% %PROTOCOL%" %RESPONSE_CODE% %RESPONSE_FLAGS% %RESPONSE_CODE_DETAILS% %CONNECTION_TERMINATION_DETAILS% "%UPSTREAM_TRANSPORT_FAILURE_REASON%" %BYTES_RECEIVED% %BYTES_SENT% %DURATION% %RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)% "%REQ(X-FORWARDED-FOR)%" "%REQ(USER-AGENT)%" "%REQ(X-REQUEST-ID)%" "%REQ(:AUTHORITY)%" "%UPSTREAM_HOST%" %UPSTREAM_CLUSTER% %UPSTREAM_LOCAL_ADDRESS% %DOWNSTREAM_LOCAL_ADDRESS% %DOWNSTREAM_REMOTE_ADDRESS% %REQUESTED_SERVER_NAME% %ROUTE_NAME% traceID=%REQ(x-b3-traceid)%
   enableTracing: true
   defaultConfig:
     tracing:
       sampling: 100
       max_path_tag_length: 99999
       zipkin:
         address: otel-collector.tracing.svc:9411
EOF

Install the demo application

Let’s create the namespace and label it to auto-inject the istio proxy:

kubectl create ns bookinfo
kubectl label namespace bookinfo istio-injection=enabled --overwrite

And now the demo application bookinfo:

kubectl apply -n bookinfo -f https://raw.githubusercontent.com/istio/istio/release-1.10/samples/bookinfo/platform/kube/bookinfo.yaml

To access the application through Istio, you need to configure it. It is required a Gateway and a VirtualService:

kubectl apply  -f - << 'EOF'
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
 name: bookinfo-gateway
 namespace: bookinfo
spec:
 selector:
   istio: ingressgateway # use istio default controller
 servers:
 - port:
     number: 80
     name: http
     protocol: HTTP
   hosts:
   - "*" # Mind the hosts. This matches all
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
 name: bookinfo
 namespace: bookinfo
spec:
 hosts:
 - "*"
 gateways:
 - tracing/bookinfo-gateway
 - bookinfo-gateway
 http:
 - match:
   - uri:
       prefix: "/"
   route:
   - destination:
       host: productpage.bookinfo.svc.cluster.local
       port:
         number: 9080
EOF

To access the application, let’s open a tunnel to the Istio ingress gateway (the entry point to the mesh):

kubectl port-forward svc/istio-ingressgateway -n istio-system  8080:80

Now, you can access the application through the browser: http://localhost:8080/productpage

Install grafana stack

Now, let’s create the grafana components. Let’s start with Tempo, the tracing backend we have mentioned before:

kubectl create ns tracing
helm repo add grafana https://grafana.github.io/helm-charts
helm repo update
helm install tempo grafana/tempo --version 0.7.4 -n tracing -f - << 'EOF'
tempo:
 extraArgs:
   "distributor.log-received-traces": true
 receivers:
   zipkin:
   otlp:
     protocols:
       http:
       grpc:
EOF

Next component. Let’s create a simple deployment of Loki:

helm install loki grafana/loki-stack --version 2.4.1 -n tracing -f - << 'EOF'
fluent-bit:
 enabled: false
promtail:
 enabled: false
prometheus:
 enabled: true
 alertmanager:
   persistentVolume:
     enabled: false
 server:
   persistentVolume:
     enabled: false
EOF

Now, let’s deploy Opentelemetry Collector. You use this component to distribute the traces across your infrastructure:

kubectl apply -n tracing -f https://raw.githubusercontent.com/antonioberben/examples/master/opentelemetry-collector/otel.yaml
kubectl apply -n tracing -f - << 'EOF'
apiVersion: v1
kind: ConfigMap
metadata:
 name: otel-collector-conf
 labels:
   app: opentelemetry
   component: otel-collector-conf
data:
 otel-collector-config: |
   receivers:   
     zipkin:
       endpoint: 0.0.0.0:9411
   exporters:
     otlp:
       endpoint: tempo.tracing.svc.cluster.local:55680
       insecure: true
   service:
     pipelines:
       traces:
         receivers: [zipkin]
         exporters: [otlp]
EOF

Following component is fluent-bit. You will use this component to scrap the log traces from your cluster. Note: In the configuration you are specifying to take only containers which match following pattern /var/log/containers/*istio-proxy*.log

helm repo add fluent https://fluent.github.io/helm-charts
helm repo update
helm install fluent-bit fluent/fluent-bit --version 0.16.1 -n tracing -f - << 'EOF'
logLevel: trace
config:
 service: |
   [SERVICE]
       Flush 1
       Daemon Off
       Log_Level trace
       Parsers_File custom_parsers.conf
       HTTP_Server On
       HTTP_Listen 0.0.0.0
       HTTP_Port {{ .Values.service.port }}
 inputs: |
   [INPUT]
       Name tail
       Path /var/log/containers/*istio-proxy*.log
       Parser cri
       Tag kube.*
       Mem_Buf_Limit 5MB
 outputs: |
   [OUTPUT]
       name loki
       match *
       host loki.tracing.svc
       port 3100
       tenant_id ""
       labels job=fluentbit
       label_keys $trace_id
       auto_kubernetes_labels on
 customParsers: |
   [PARSER]
       Name cri
       Format regex
       Regex ^(?<time>[^ ]+) (?<stream>stdout|stderr) (?<logtag>[^ ]*) (?<message>.*)$
       Time_Key    time
       Time_Format %Y-%m-%dT%H:%M:%S.%L%z
EOF

Now, the grafana query. This component is already configured to connect to Loki and Tempo:

helm install grafana grafana/grafana -n tracing --version 6.13.5  -f - << 'EOF'
datasources:
 datasources.yaml:
   apiVersion: 1
   datasources:
     - name: Tempo
       type: tempo
       access: browser
       orgId: 1
       uid: tempo
       url: http://tempo.tracing.svc:3100
       isDefault: true
       editable: true
     - name: Loki
       type: loki
       access: browser
       orgId: 1
       uid: loki
       url: http://loki.tracing.svc:3100
       isDefault: false
       editable: true
       jsonData:
         derivedFields:
           - datasourceName: Tempo
             matcherRegex: "traceID=(\\w+)"
             name: TraceID
             url: "$${__value.raw}"
             datasourceUid: tempo
env:
 JAEGER_AGENT_PORT: 6831
adminUser: admin
adminPassword: password
service:
 type: LoadBalancer
EOF

Test it

After the installations are completed, let’s open a tunnel to grafana query forwarding the port:

kubectl port-forward svc/grafana -n tracing 8081:80

Access it using the credentials you have configured when you have installed it:

user: admin
password: password

http://localhost:8081/explore

You are prompted to the Explore tab. There, you can select Loki to be displayed on one side and, after click on split, to choose Tempo to be displayed in the other side:

Tempo Grafana

You will see something like this:

Tempo Grafana response
Finally, let’s create some traffic with the tunnel we already created to bookinfo application:

http://localhost:8080/productpage

Refresh (hard refresh to avoid cache) the page several times until you can see traces coming into Loki. Remember to add the filter to `ProductPage` to see its access log traces:

Tempo Grafana Loki
Click on the log and a Tempo button is shown:

Immediately, the TraceID will be passed to the Tempo dashboard displaying the traceability and the diagram:

Tempo Grafana TraceID

Grafana TraceID 2

Final thoughts

Having a diagram which displays all elements involved in a request through a microservices increases the speed to find bugs or to understand what happened in your system when running a postmortem analysis. Reducing that time, you increase efficiency so that your developers can keep working and producing more business requirements. In my personal opinion, that is the key point: Increase the business productivity. Traceability and, in this case, grafana stack helps you to accomplish that.

Now, let’s make it production ready.