Debug Dapr in Kubernetes mode

• 1: Debug Dapr control plane on Kubernetes
• 2: Debug daprd on Kubernetes

1 - Debug Dapr control plane on Kubernetes

Overview

Sometimes it is necessary to understand what’s going on in Dapr control plane (aka, Kubernetes services), including dapr-sidecar-injector, dapr-operator, dapr-placement, and dapr-sentry, especially when you diagnose your Dapr application and wonder if there’s something wrong in Dapr itself. Additionally, you may be developing a new feature for Dapr on Kubernetes and want to debug your code.

This guide will cover how to use Dapr debugging binaries to debug the Dapr services on your Kubernetes cluster.

Debugging Dapr Kubernetes services

Pre-requisites

• Familiarize yourself with this guide to learn how to deploy Dapr to your Kubernetes cluster.
• Setup your dev environment
• Helm

1. Build Dapr debugging binaries

In order to debug Dapr Kubernetes services, it’s required to rebuild all Dapr binaries and Docker images to disable compiler optimization. To do this, execute the following commands:

git clone https://github.com/dapr/dapr.git
cd dapr
make release GOOS=linux GOARCH=amd64 DEBUG=1

On Windows download MingGW and use ming32-make.exe instead of make.

In the above command, ‘DEBUG’ is specified to ‘1’ to disable compiler optimization. ‘GOOS=linux’ and ‘GOARCH=amd64’ are also necessary since the binaries will be packaged into Linux-based Docker image in the next step.

The binaries could be found under ‘dist/linux_amd64/debug’ sub-directory under the ‘dapr’ directory.

2. Build Dapr debugging Docker images

Use the following commands to package the debugging binaries into Docker images. Before this, you need to login your docker.io account, and if you don’t have it yet, you may need to consider registering one from “https://hub.docker.com/".

export DAPR_TAG=dev
export DAPR_REGISTRY=<your docker.io id>
docker login
make docker-push DEBUG=1

Once the Dapr Docker images are built and pushed onto Docker hub, then you are ready to re-install Dapr in your Kubernetes cluster.

3. Install Dapr debugging binaries

If Dapr has already been installed in your Kubernetes cluster, uninstall it first:

dapr uninstall -k

We will use ‘helm’ to install Dapr debugging binaries. In the following sections, we will use Dapr operator as an example to demonstrate how to configure, install, and debug Dapr services in a Kubernetes environment.

First configure a values file with these options:

global:
   registry: docker.io/<your docker.io id>
   tag: "dev-linux-amd64"
dapr_operator:
  debug:
    enabled: true
    initialDelaySeconds: 3000

Then step into ‘dapr’ directory which’s cloned from GitHub in the beginning of this guide if you haven’t, and execute the following command:

helm install dapr charts/dapr --namespace dapr-system --values values.yml --wait

4. Forward debugging port

To debug the target Dapr service (Dapr operator in this case), its pre-configured debug port needs to be visible to your IDE. In order to achieve this, we need to find the target Dapr service’s pod first:

$ kubectl get pods -n dapr-system -o wide

NAME                                     READY   STATUS    RESTARTS   AGE   IP            NODE       NOMINATED NODE   READINESS GATES
dapr-dashboard-64b46f98b6-dl2n9          1/1     Running   0          61s   172.17.0.9    minikube   <none>           <none>
dapr-operator-7878f94fcd-6bfx9           1/1     Running   1          61s   172.17.0.7    minikube   <none>           <none>
dapr-placement-server-0                  1/1     Running   1          61s   172.17.0.8    minikube   <none>           <none>
dapr-sentry-68c7d4c7df-sc47x             1/1     Running   0          61s   172.17.0.6    minikube   <none>           <none>
dapr-sidecar-injector-56c8f489bb-t2st9   1/1     Running   0          61s   172.17.0.10   minikube   <none>           <none>

Then use kubectl’s port-forward command to expose the internal debug port to the external IDE:

$ kubectl port-forward dapr-operator-7878f94fcd-6bfx9 40000:40000 -n dapr-system

Forwarding from 127.0.0.1:40000 -> 40000
Forwarding from [::1]:40000 -> 40000

All done. Now you can point to port 40000 and start a remote debug session from your favorite IDE.

Related links

• Overview of Dapr on Kubernetes
• Deploy Dapr to a Kubernetes cluster
• Dapr Kubernetes Quickstart

2 - Debug daprd on Kubernetes

Overview

Sometimes it is necessary to understand what’s going on in the Dapr sidecar (daprd), which runs as a sidecar next to your application, especially when you diagnose your Dapr application and wonder if there’s something wrong in Dapr itself. Additionally, you may be developing a new feature for Dapr on Kubernetes and want to debug your code.

This guide covers how to use built-in Dapr debugging to debug the Dapr sidecar in your Kubernetes pods. To learn how to view logs and troubleshoot Dapr in Kubernetes, see the Configure and view Dapr logs guide

Pre-requisites

• Refer to this guide to learn how to deploy Dapr to your Kubernetes cluster.
• Follow this guide to build the Dapr debugging binaries you will be deploying in the next step.

Initialize Dapr in debug mode

If Dapr has already been installed in your Kubernetes cluster, uninstall it first:

dapr uninstall -k

We will use ‘helm’ to install Dapr debugging binaries. For more information refer to Install with Helm.

First configure a values file named values.yml with these options:

global:
   registry: docker.io/<your docker.io id>
   tag: "dev-linux-amd64"

Then step into ‘dapr’ directory from your cloned dapr/dapr repository and execute the following command:

helm install dapr charts/dapr --namespace dapr-system --values values.yml --wait

To enable debug mode for daprd, you need to put an extra annotation dapr.io/enable-debug in your application’s deployment file. Let’s use quickstarts/hello-kubernetes as an example. Modify ‘deploy/node.yaml’ like below:

diff --git a/hello-kubernetes/deploy/node.yaml b/hello-kubernetes/deploy/node.yaml
index 23185a6..6cdb0ae 100644
--- a/hello-kubernetes/deploy/node.yaml
+++ b/hello-kubernetes/deploy/node.yaml
@@ -33,6 +33,7 @@ spec:
         dapr.io/enabled: "true"
         dapr.io/app-id: "nodeapp"
         dapr.io/app-port: "3000"
+        dapr.io/enable-debug: "true"
     spec:
       containers:
       - name: node

The annotation dapr.io/enable-debug will hint Dapr injector to inject Dapr sidecar into the debug mode. You can also specify the debug port with annotation dapr.io/debug-port, otherwise the default port will be “40000”.

Deploy the application with the following command. For the complete guide refer to the Dapr Kubernetes Quickstart:

kubectl apply -f ./deploy/node.yaml

Figure out the target application’s pod name with the following command:

$ kubectl get pods

NAME                       READY   STATUS        RESTARTS   AGE
nodeapp-78866448f5-pqdtr   1/2     Running       0          14s

Then use kubectl’s port-forward command to expose the internal debug port to the external IDE:

$ kubectl port-forward nodeapp-78866448f5-pqdtr 40000:40000

Forwarding from 127.0.0.1:40000 -> 40000
Forwarding from [::1]:40000 -> 40000

All done. Now you can point to port 40000 and start a remote debug session to daprd from your favorite IDE.

Commonly used kubectl commands

Use the following common kubectl commands when debugging daprd and applications running on Kubernetes.

Get all pods, events, and services:

kubectl get all
kubectl get all --n <namespace>
kubectl get all --all-namespaces

Get each specifically:

kubectl get pods

kubectl get events --n <namespace>
kubectl get events --sort-by=.metadata.creationTimestamp --n <namespace>

kubectl get services

Check logs:

kubectl logs <podId> daprd
kubectl logs <podId> <myAppContainerName>
kuebctl logs <deploymentId> daprd
kubectl logs <deploymentId> <myAppContainerName>

kubectl describe pod <podId>
kubectl describe deploy <deployId>
kubectl describe replicaset <replicasetId>

Restart a pod by running the following command:

kubectl delete pod <podId>

This causes the replicaset controller to restart the pod after the delete.

Watch the demo

See the presentation on troubleshooting Dapr on Kubernetes in the Dapr Community Call #36.

Related links

• Overview of Dapr on Kubernetes
• Deploy Dapr to a Kubernetes cluster
• Debug Dapr services on Kubernetes
• Dapr Kubernetes Quickstart