Testing & Development


Setup a Kubernetes cluster

A minimal Kubernetes cluster can be easily setup locally using either of the following -

For the ease of illustration and testing, we will conform to using Docker Desktop for the rest of the guide.

Docker Desktop

Download Docker Desktop

mirrord - Download Docker Desktop

Enable Kubernetes in preferences, Apply and Restart

mirrord - Download Docker Desktop

Preparing a cluster

Switch Kubernetes context to docker-desktop

kubectl config get-contexts
kubectl config use-context docker-desktop

From the root directory of the mirrord repository, create a new testing deployment and service:

kubectl apply -f sample/kubernetes/app.yaml
apiVersion: apps/v1
kind: Deployment
  name: py-serv-deployment
    app: py-serv
  replicas: 1
      app: py-serv
        app: py-serv
        - name: py-serv
          image: ghcr.io/metalbear-co/mirrord-pytest:latest
            - containerPort: 80
            - name: MIRRORD_FAKE_VAR_FIRST
              value: mirrord.is.running
            - name: MIRRORD_FAKE_VAR_SECOND
              value: "7777"

apiVersion: v1
kind: Service
    app: py-serv
  name: py-serv
    - port: 80
      protocol: TCP
      targetPort: 80
      nodePort: 30000
    app: py-serv
  sessionAffinity: None
  type: NodePort

Verify everything was created after applying the manifest

❯ kubectl get services
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP      <none>        443/TCP        3h13m
py-serv      NodePort   <none>        80:30000/TCP   3h8m
❯ kubectl get deployments
py-serv-deployment   1/1     1            1           3h8m
❯ kubectl get pods
NAME                                 READY   STATUS    RESTARTS   AGE
py-serv-deployment-ff89b5974-x9tjx   1/1     Running   0          3h8m

Build mirrord-agent Docker Image

docker build -t test . --file mirrord/agent/Dockerfile
❯ docker images
REPOSITORY                                     TAG       IMAGE ID       CREATED         SIZE
test                                           latest    5080c20a8222   2 hours ago     300MB

Note: mirrord-agent is shipped as a container image as it creates a job with this image, providing it with elevated permissions on the same node as the impersonated pod.

Build and run mirrord

OSXcargo +nightly build --workspace --exclude mirrord-agent
Linuxcargo +nightly build

Run mirrord with a local process

Sample web server - app.js

import { Buffer } from "node:buffer";
import { createServer } from "net";
import { open, readFile } from "fs/promises";

async function debug_file_ops() {
  try {
    const readOnlyFile = await open("/var/log/dpkg.log", "r");
    console.log(">>>>> open readOnlyFile ", readOnlyFile);

    let buffer = Buffer.alloc(128);
    let bufferResult = await readOnlyFile.read(buffer);
    console.log(">>>>> read readOnlyFile returned with ", bufferResult);

    const sampleFile = await open("/tmp/node_sample.txt", "w+");
    console.log(">>>>> open file ", sampleFile);

    const written = await sampleFile.write("mirrord sample node");
    console.log(">>>>> written ", written, " bytes to file ", sampleFile);

    let sampleBuffer = Buffer.alloc(32);
    let sampleBufferResult = await sampleFile.read(buffer);
    console.log(">>>>> read ", sampleBufferResult, " bytes from ", sampleFile);

  } catch (fail) {
    console.error("!!! Failed file operation with ", fail);

// debug_file_ops();

const server = createServer();
server.on("connection", handleConnection);
    host: "localhost",
    port: 80,
  function () {
    console.log("server listening to %j", server.address());

function handleConnection(conn) {
  var remoteAddress = conn.remoteAddress + ":" + conn.remotePort;
  console.log("new client connection from %s", remoteAddress);
  conn.on("data", onConnData);
  conn.once("close", onConnClose);
  conn.on("error", onConnError);

  function onConnData(d) {
    console.log("connection data from %s: %j", remoteAddress, d.toString());
  function onConnClose() {
    console.log("connection from %s closed", remoteAddress);
  function onConnError(err) {
    console.log("Connection %s error: %s", remoteAddress, err.message);
MIRRORD_AGENT_IMAGE=test MIRRORD_AGENT_RUST_LOG=debug RUST_LOG=debug target/debug/mirrord exec -c --target pod/py-serv-deployment-ff89b5974-x9tjx node sample/node/app.mjs

Note: You need to change the pod name here to the name of the pod created on your system.

2022-06-30T05:14:01.592418Z DEBUG hyper::proto::h1::io: flushed 299 bytes
2022-06-30T05:14:01.657977Z DEBUG hyper::proto::h1::io: parsed 4 headers
2022-06-30T05:14:01.658075Z DEBUG hyper::proto::h1::conn: incoming body is empty
2022-06-30T05:14:01.661729Z DEBUG rustls::conn: Sending warning alert CloseNotify
2022-06-30T05:14:01.678534Z DEBUG mirrord_layer::sockets: getpeername hooked
2022-06-30T05:14:01.678638Z DEBUG mirrord_layer::sockets: getsockname hooked
2022-06-30T05:14:01.678713Z DEBUG mirrord_layer::sockets: accept hooked
2022-06-30T05:14:01.905378Z DEBUG mirrord_layer::sockets: socket called domain:30, type:1
2022-06-30T05:14:01.905639Z DEBUG mirrord_layer::sockets: bind called sockfd: 32
2022-06-30T05:14:01.905821Z DEBUG mirrord_layer::sockets: bind:port: 80
2022-06-30T05:14:01.906029Z DEBUG mirrord_layer::sockets: listen called
2022-06-30T05:14:01.906182Z DEBUG mirrord_layer::sockets: bind called sockfd: 32
2022-06-30T05:14:01.906319Z DEBUG mirrord_layer::sockets: bind: no socket found for fd: 32
2022-06-30T05:14:01.906467Z DEBUG mirrord_layer::sockets: getsockname called
2022-06-30T05:14:01.906533Z DEBUG mirrord_layer::sockets: getsockname: no socket found for fd: 32
2022-06-30T05:14:01.906852Z DEBUG mirrord_layer::sockets: listen: success
2022-06-30T05:14:01.907034Z DEBUG mirrord_layer::tcp: handle_listen -> listen Listen {
    fake_port: 51318,
    real_port: 80,
    ipv6: true,
    fd: 32,
Server listening on port 80

Send traffic to the Kubernetes Pod through the service

curl localhost:30000

Check the traffic was received by the local process

2022-06-30T05:17:31.877560Z DEBUG mirrord_layer::tcp: handle_incoming_message -> message Close(
    TcpClose {
        connection_id: 0,
2022-06-30T05:17:31.877608Z DEBUG mirrord_layer::tcp_mirror: handle_close -> close TcpClose {
    connection_id: 0,
2022-06-30T05:17:31.877655Z DEBUG mirrord_layer::tcp: handle_incoming_message -> handled Ok(
2022-06-30T05:17:31.878193Z  WARN mirrord_layer::tcp_mirror: tcp_tunnel -> exiting due to remote stream closed!
2022-06-30T05:17:31.878255Z DEBUG mirrord_layer::tcp_mirror: tcp_tunnel -> exiting
OK - GET: Request completed

Run E2E tests

Run Cargo test

cargo test --package tests