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Troubleshooting

There are two target platforms for OpenFaaS, and depending on which you are using, some of the instructions will differ.

faasd

The troubleshooting instructions for faasd are only available in the eBook and manual.

OpenFaaS on Kubernetes

Kubernetes is a complex distributed system, and there are many things that can cause friction for new users. This guide is devoted to helping you help yourself.

If you want to ask for help, make sure that you have run all of the commands below before doing so. Be prepared with a text file that you can upload to Slack as a snippet, or that you can email in, or attach to a GitHub issue.

OpenFaaS didn't start

Look for 0/1, restarts or errors showing up here:

kubectl get deploy -n openfaas

Next, try to describe one of the deployments such as the gateway:

kubectl describe -n openfaas deploy/gateway

Next, check the logs for the specific deployment that is failing to start:

kubectl logs -n openfaas deploy/gateway

Next, check the events in the openfaas namespace:

kubectl get events -n openfaas \
  --sort-by=.metadata.creationTimestamp 

Common issues:

  • Have you forgotten to create the password required for the gateway?
  • The gateway must be able to talk to nats and prometheus. If these are crashing, you probably have networking issues preventing containers from talking to each over or looking up each other over DNS.
  • Have you got enough resources free in your cluster for all the services to start? kubectl describe nodes or kubectl top node should give you some hints here.

My function didn't start

Look for 0/1, restarts or errors showing up here:

kubectl get deploy -n openfaas-fn

Next, try to describe one of the deployments such as the nodeinfo:

kubectl describe -n openfaas-fn deploy/nodeinfo

Next, check the logs for the specific deployment that is failing to start:

kubectl logs -n openfaas-fn deploy/nodeinfo

Next, check the events in the openfaas-fn namespace:

kubectl get events -n openfaas-fn \
  --sort-by=.metadata.creationTimestamp 

Common issues:

  • You are using a private registry, but haven't configured any image pull secrets. See: Kubernetes deployment instructions
  • You haven't created a secret which is required for your function to start. Check your function request or stack.yml, and create any missing secrets.
  • Your function is crashing due to an error in your code, check the logs.

My function is timing out

Check the logs of the gateway for signs of a time-out, or non-200 HTTP code:

kubectl logs -n openfaas deploy/gateway -c gateway

Do the same for the provider:

kubectl logs -n openfaas deploy/gateway -c faas-netes

# Or, if you are using the CRD and Operator:
kubectl logs -n openfaas deploy/gateway -c operator

If your function is timing out and you are calling it asynchronously, then check the queue-worker's logs:

kubectl logs -n openfaas deploy/queue-worker

Check the logs of the function

faas-cli logs NAME

Common issues: * You are using a service mesh, and therefore must set direct_functions to true so that the gateway uses the name of the function to resolve it * You have not configured a high enough timeout on all the required components. See Expanded timeouts * You are trying to access the gateway from your function, you must use the string http://gateway.openfaas:8080, otherwise it will be unreachable to you. * Your cloud LoadBalancer may have a timeout set of 60 seconds, which could prevent your call from executing successfully, consider increasing the timeout if you can, or execute the function asynchronously.

My function takes too long to start up

Your function is failing because it takes too long to start-up.

  • Learn how to configure a custom HTTP health-check that you can respond to from your function
  • Learn how to extend the window between your function starting, and its initial health-check run

See: Custom HTTP health check

I want to test my function without deploying it

You can usually do one of the following:

  • Use unit-testing in the language of your choice (fastest)
  • Use faas-cli build followed by docker run (easy)
  • Try hot-reloading with docker-compose (advanced)

Example:

faas-cli new --lang go test-this
faas-cli build -f test-this.yml

docker run -p 8080:8080 --name test-this \
 -ti test-this:latest

Then invoke your function via http://127.0.0.1:8080.

If you need to set environment variable, or to simulate secrets being mounted, you can do so with --env/-e and -v to simulate mounting secrets at /var/openfaas/secrets.

I forgot my credentials for the gateway

Download arkade.

Now run the following command which will give you the commands you require to retrieve your password.

arkade info openfaas

Alternatively, consider using the Single-Sign On module from OpenFaaS PRO.

Traffic is not being spread evenly between functions

You will need to ensure that you are doing one of the following:

  • Setting direct_functions to false, which allows the provider to balance calls randomly between replicas of your functions.
  • Use a service mesh like Linkerd or Istio, which can do advanced traffic-management such as least-connections

I want to remove OpenFaaS from a cluster

See the Helm chart instructions

How can I use structured logs in my function

By default, the logs will be in the format

<RCF8601 Timestamp> <function name> (<container instance>) <msg>

By setting the environment variable prefix_logs to false in your function, this will only send the <msg> part to the terminal. This allows you to use structured logs that outputs a JSON (or equivalent) payload.

See the Logs documentation for more details.