Debugging istio rate limiting handler - redis

Question

I'm trying to apply rate limiting on some of our internal services (inside the mesh).
I used the example from the docs and generated redis rate limiting configurations that include a (redis) handler, quota instance, quota spec, quota spec binding and rule to apply the handler.
This redis handler:
apiVersion: config.istio.io/v1alpha2
kind: handler
metadata:
name: redishandler
namespace: istio-system
spec:
compiledAdapter: redisquota
params:
redisServerUrl: <REDIS>:6379
connectionPoolSize: 10
quotas:
- name: requestcountquota.instance.istio-system
maxAmount: 10
validDuration: 100s
rateLimitAlgorithm: FIXED_WINDOW
overrides:
- dimensions:
destination: s1
maxAmount: 1
- dimensions:
destination: s3
maxAmount: 1
- dimensions:
destination: s2
maxAmount: 1
The quota instance (I'm only interested in limiting by destination at the moment):
apiVersion: config.istio.io/v1alpha2
kind: instance
metadata:
name: requestcountquota
namespace: istio-system
spec:
compiledTemplate: quota
params:
dimensions:
destination: destination.labels["app"] | destination.service.host | "unknown"
A quota spec, charging 1 per request if I understand correctly:
apiVersion: config.istio.io/v1alpha2
kind: QuotaSpec
metadata:
name: request-count
namespace: istio-system
spec:
rules:
- quotas:
- charge: 1
quota: requestcountquota
A quota binding spec that all participating services pre-fetch. I also tried with service: "*" which also did nothing.
apiVersion: config.istio.io/v1alpha2
kind: QuotaSpecBinding
metadata:
name: request-count
namespace: istio-system
spec:
quotaSpecs:
- name: request-count
namespace: istio-system
services:
- name: s2
namespace: default
- name: s3
namespace: default
- name: s1
namespace: default
# - service: '*' # Uncomment this to bind *all* services to request-count
A rule to apply the handler. Currently on all occasions (tried with matches but didn't change anything as well):
apiVersion: config.istio.io/v1alpha2
kind: rule
metadata:
name: quota
namespace: istio-system
spec:
actions:
- handler: redishandler
instances:
- requestcountquota
The VirtualService definitions are pretty similar for all participants:
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: s1
spec:
hosts:
- s1
http:
- route:
- destination:
host: s1
The problem is nothing really happens and no rate limiting takes place. I tested with curl from pods inside the mesh. The redis instance is empty (no keys on db 0, which I assume is what the rate limiting would use) so I know it can't practically rate-limit anything.
The handler seems to be configured properly (how can I make sure?) because I had some errors in it which were reported in mixer (policy). There are still some errors but none which I associate to this problem or the configuration. The only line in which redis handler is mentioned is this:
2019-12-17T13:44:22.958041Z info adapters adapter closed all scheduled daemons and workers {"adapter": "redishandler.istio-system"}
But its unclear if its a problem or not. I assume its not.
These are the rest of the lines from the reload once I deploy:
2019-12-17T13:44:22.601644Z info Built new config.Snapshot: id='43'
2019-12-17T13:44:22.601866Z info adapters getting kubeconfig from: "" {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.601881Z warn Neither --kubeconfig nor --master was specified. Using the inClusterConfig. This might not work.
2019-12-17T13:44:22.602718Z info adapters Waiting for kubernetes cache sync... {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.903844Z info adapters Cache sync successful. {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.903878Z info adapters getting kubeconfig from: "" {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.903882Z warn Neither --kubeconfig nor --master was specified. Using the inClusterConfig. This might not work.
2019-12-17T13:44:22.904808Z info Setting up event handlers
2019-12-17T13:44:22.904939Z info Starting Secrets controller
2019-12-17T13:44:22.904991Z info Waiting for informer caches to sync
2019-12-17T13:44:22.957893Z info Cleaning up handler table, with config ID:42
2019-12-17T13:44:22.957924Z info adapters deleted remote controller {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.957999Z info adapters adapter closed all scheduled daemons and workers {"adapter": "prometheus.istio-system"}
2019-12-17T13:44:22.958041Z info adapters adapter closed all scheduled daemons and workers {"adapter": "redishandler.istio-system"}
2019-12-17T13:44:22.958065Z info adapters shutting down daemon... {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.958050Z info adapters shutting down daemon... {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.958096Z info adapters shutting down daemon... {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:22.958182Z info adapters shutting down daemon... {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:44:23.958109Z info adapters adapter closed all scheduled daemons and workers {"adapter": "kubernetesenv.istio-system"}
2019-12-17T13:55:21.042131Z info transport: loopyWriter.run returning. connection error: desc = "transport is closing"
2019-12-17T14:14:00.265722Z info transport: loopyWriter.run returning. connection error: desc = "transport is closing"
I'm using the demo profile with disablePolicyChecks: false to enable rate limiting. This is on istio 1.4.0, deployed on EKS.
I also tried memquota (this is our staging environment) with low limits and nothing seems to work. I never got a 429 no matter how much I went over the rate limit configured.
I don't know how to debug this and see where the configuration is wrong causing it to do nothing.
Any help is appreciated.

Answer 1

I too spent hours trying to decipher the documentation and get a sample working.
According to the documentation, they recommended that we enable policy checks:
https://istio.io/docs/tasks/policy-enforcement/rate-limiting/
However when that did not work, I did an "istioctl profile dump", searched for policy, and tried several settings.
I used Helm install and passed the following and then was able to get the described behaviour:
--set global.disablePolicyChecks=false \
--set values.pilot.policy.enabled=true \ ===> this made it work, but it's not in the docs.