pingo

PinGo

Overview

PinGo is a simple application to measure network availability from a source (where it runs) to target nodes (acquired from Kubernetes API).

How it Works?

It keeps connecting to a Kubernetes API to get a list of nodes with their IP addresses and Kubelet port (60s default). For each node, one probe is created and handled, this will loop with an interval (15s default), trying to establish a TCP connection (3 way handshake), measuring reply, time and lost.

graph TD
    style A fill:#0e0,stroke:#010,stroke-width:3px;
    style B fill:#e0e,stroke:#101,stroke-width:2px;
    style C fill:#e0e,stroke:#101,stroke-width:2px;
    style D fill:#eee,stroke:#111,stroke-width:1px;
    style E fill:#ee0,stroke:#110,stroke-width:2px;
    style F fill:#0ee,stroke:#011,stroke-width:2px;
    style G fill:#e0e,stroke:#101,stroke-width:2px;
    style H fill:#eee,stroke:#111,stroke-width:1px;
    A(PinGo) -->|goroutine| B(Scan)
    A -->|goroutine| C(Collect)
    A -->|goroutine| G(HTTP Server)
    B <-.->|get nodes| D{API}
    B -->|goroutine| E(Probe)
    E -->|metrics channel| C
    C -->|render template| F[Board]
    F -->|read buffer| G
    G -.->|write metrics| H{cient}
    B -->|kill channel| E

Metrics are Prometheus formatted and published through HTTP in order to be collected by third party monitoring.

Example

1. Set Kubernetes API Endpoint

export PINGO_API=https://KUBERNETES_API:PORT

1. Set Authentication Token

⚠ Service Account must have a bind to a cluster role allowing get and list over objects nodes.

export PINGO_TOKEN=SERVICE_ACCOUNT_TOKEN

1. Set API Certificate Authority as Base64

export PINGO_CA=BASE64_KUBERNETES_API_CERTIFICATE

ℹ To get API certificate use this command after replace KUBERNETES_API:PORT.

export PINGO_CA=`echo "" | openssl s_client -connect KUBERNETES_API:PORT -prexit 2>/dev/null | sed -n -e '/BEGIN\ CERTIFICATE/,/END\ CERTIFICATE/ p' | base64 -w0`

1. Run the Application

./pingo

Build

No external dependencies, just builtin Go libraries.

CGO_ENABLED=0 go build -o pingo pingo.go

History

I wrote this software in order to uncover a suspected network issue between two Kubernetes clusters sharing a cache.