Istio Latency Analysis

README.md

Istio Performance Analysis

The goal of this experiment is to measure the amount of latency that is added to a simple service by the addition of various Istio Components. To isolate the contribution of each component, many combinations of avialable components were tested and recorded.

Components

• Sidecar
• Istio Ingress
• Load Balancer Ingress

Other Parameters

• Scale: 1 or 5 instances of services and ingress
• Service: Single HTTP server or frontend/backend combo

Methodology

Each combination of Parameters was tested using a fortio client running inside the cluster, with 64 concurrent connections for 30 seconds. First the max QPS was measured (using -qps 0), then a second test was run at 75% load as per fortio recommendations, and the P50 and P99 latencies were observed.

Reproducing this study

Isotope files

• frontend.yaml - includes two services in frontend/backend configuration
• singleton.yaml - includes minimalist service that responds to requests immediately. To generate kubernetes yaml for these scenarios, run:

go run $GOPATH/src/istio.io/isotope/converter/main.go kubernetes --service-image gcr.io/istio-testing/isotope:0.0.1 singleton.yaml | kubectl apply -f -

Load generator files (fortio used for this experiment, wrk for comparison)

• fortio.yaml
• wrk.yaml

For example, to test latency with no sidecar or ingress on the frontend service using the fortio pod above, run:

kubectl exec deployment/client -- fortio load -qps 0 -c 64 -t 30s http://go-sample:8080

The last line of output for the above command will include the maximum qps of the service in this configuration. Multiply that value by 75%, and run:

kubectl exec deployment/client -- fortio load -qps [75%] -c 64 -t 30s http://go-sample:8080

Which will give realistic results for a service under 75% of maximum load.

Results

Svc	Scale	Istio Ingress	Istio Sidecar	P99	P50	MaxQPS
single	1	No	No	0.002662	0.000612	64000
double	1	No	No	0.447564	0.006938	1837
single	1	Istio	No	0.023874	0.009830	5347
double	1	Istio	No	0.367515	0.018978	1300
single	1	Istio	Istio	0.029908	0.014137	4382
double	1	Istio	Istio	0.294953	0.046129	943
single	1	No	Istio	0.017214	0.009103	6400
double	1	No	Istio	0.273101	0.036778	1095
single	5	No	No	0.00226841	0.00057761	98789
double	5	No	No	0.0619578	0.00283516	9454
single	5	Istio	No	0.0819547	0.00272854	11690
double	5	Istio	No	0.113905	0.00507379	4745
single	5	Istio	Istio	0.0319723	0.00660786	6475
double	5	Istio	Istio	0.0541879	0.0147881	2796
single	5	No	Istio	0.0113906	0.00360995	17484
double	5	No	Istio	0.0660513	0.0130243	4301

fortio.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: client
  name: client
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: client
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      annotations:
        prometheus.io/scrape: "true"
        sidecar.istio.io/inject: "false"
      creationTimestamp: null
      labels:
        app: client
    spec:
      containers:
      - args:
        - server
        image: fortio/fortio
        imagePullPolicy: Always
        name: fortio
        ports:
        - containerPort: 8080
          name: fortio-web
          protocol: TCP
        - containerPort: 42422
          protocol: TCP
        resources: 
          requests:
            cpu: "2"
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30

simple.yaml

apiVersion: v1alpha1
kind: MockServiceGraph
defaults:
  type: http
  requestSize: 1 B
  responseSize: 1 B
services:
- name: go-sample
  script:
  - call:
      service: go-sample-dependency
- name: go-sample-dependency

singleton.yaml

defaults:
  requestSize: 1 KB
  responseSize: 1 KB
services:
- name: a
  isEntrypoint: true

wrk.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: client
  name: wrkclient
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: client
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      annotations:
        prometheus.io/scrape: "true"
        sidecar.istio.io/inject: "false"
      creationTimestamp: null
      labels:
        app: client
    spec:
      containers:
      - args:
        - server
        image: williamyeh/wrk
        imagePullPolicy: Always
        name: wrk
        ports:
        - containerPort: 8080
          name: fortio-web
          protocol: TCP
        - containerPort: 42422
          protocol: TCP
        resources: 
          requests:
            cpu: "2"
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30