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Network Emulation

Introduction​

These instructions gives the user more information how to use network emulation within specific pods.

Prerequisite​

There is need to have some preparation ready before the network emulation will work. The important part is the mutating webhook installed to the Kubernetes. The examples can be found from repo git@github.com:ERIGrid2/k8s-netem.git and especially the directories of scripts and kubernetes inside that repository.

Here are the needed commands when you are at root directory of k8s-netem repository. There might be needed to finetune aliases in scripts/dev.sh file for you environment:

# Install aliases for running bash session
source scripts/dev.sh

# Create a new namespace for riasc system
kubectl create ns riasc-system

# Create self-signed certificate for mutating webhook
create-webhook-cert

# Build k8s-netem Docker image
build-image

# This part depends on your Docker image repository 

# Add custom resource description for TrafficProfile resources
kubectl apply -f kubernetes/crd.yaml

# Register mutating webhook
kubectl -n riasc-system apply -f kubernetes/rbac.yaml
kubectl -n riasc-system apply -f kubernetes/deployment.yaml
kubectl -n riasc-system apply -f kubernetes/service.yaml
kubectl apply -f kubernetes/webhook.yaml

TrafficProfile configuration​

TrafficProfile for Flexe​

The below is one example for TrafficProfile configuration when used with Flexe traffic Emulator controller. This example describe TrafficProfile named "profile-flexe", which selects pod(s) with traffic-profile "profile-delay-jitter-flexe", has several specified netEm profiles: "ethernet", "3g" and "gprs", and every profile is running at specified times (runTime variable) and when all the profiles are run, then repeat the order again ("segments" -> repeat: true). There is also filtering configuration for egress interface gre1 ("interfaceFilter: gre1"), which filters packets destinated to "1.1.1.1/32" and using ports "443/TCP" or "53/UDP" and pods with the label "example". Another filter is using packets destinated to "8.8.8.8/32" and port "80/TCP". When packets destinated to those filtered destinations and ports, then this TrafficProfile is used for emulating network conditions.

---
apiVersion: k8s-netem.riasc.eu/v1
kind: TrafficProfile
metadata:
name: profile-flexe
spec:
interfaceFilter: gre1

podSelector:
    matchLabels:
    traffic-profile: profile-delay-jitter-flexe

type: Flexe

parameters:
    segments:
    - repeat: true

    profiles:
    - name: ethernet
    parameters:
        runTime: 30

        bandwidthUp: 100000
        bandwidthDown: 100000
        delay: 0.25
        delayVariation: 0.25
        delayCorrelation: 0
        loss: 0
        lossCorrelation: 0
        duplication: 0
        corruption: 0
        reorder: 0
        reorderCorrelation: 0

    - name: 3g
    parameters:
        runTime: 30

        bandwidthUp: 256
        bandwidthDown: 256
        delay: 200
        delayVariation: 50
        delayCorrelation: 0
        loss: 0.5
        lossCorrelation: 0
        duplication: 0.1
        corruption: 0.1
        reorder: 0.2
        reorderCorrelation: 0

    - name: gprs
    parameters:
        bandwidthUp: 60
        bandwidthDown: 60
        delay: 350
        delayVariation: 100
        delayCorrelation: 0
        loss: 0.5
        lossCorrelation: 0
        duplication: 0.1
        corruption: 0.1
        reorder: 0.2
        reorderCorrelation: 0

    - name: lte
    parameters:
        bandwidthUp: 5000
        bandwidthDown: 15000
        delay: 7.5
        delayVariation: 5
        delayCorrelation: 0
        loss: 0.025
        lossCorrelation: 0
        duplication: 0
        corruption: 0
        reorder: 0
        reorderCorrelation: 0

    - name: xdsl
    parameters:
        bandwidthUp: 2000
        bandwidthDown: 15000
        delay: 7.5
        delayVariation: 2.5
        delayCorrelation: 0
        loss: 0
        lossCorrelation: 0
        duplication: 0
        corruption: 0
        reorder: 0
        reorderCorrelation: 0

egress:
- to:
    - ipBlock:
        cidr: 1.1.1.1/32

    - podSelector:
        matchLabels:
        component: example

    ports:
    - port: 443
    protocol: TCP
    - port: 53
    protocol: UDP

- to:
    - ipBlock:
        cidr: 8.8.8.8/32

- ports:
    - port: 80
    protocol: tcp

Usage​

When the modifications are done to file kubernetes/example/profile-flexe.yaml, then load that to the Kubernetes cluster. After that load also example deployment configuration (see kubernetes/example/deployment.yaml file). 

source scripts/dev.sh

kubectl create ns my-app

# Create the example deployment and profile only for the first time
kubectl -n my-app apply -f kubernetes/example/profile-flexe.yaml
kubectl -n my-app apply -f kubernetes/example/deployment.yaml

# Rebuild k8s-netem Docker image and restart example deployment
example-run

# Use the following commands to inspect the logs of the example deployment and webhook
webhook-logs
sidecar-logs
example-logs ping-cloudflare
example-logs ping-google