amaya382/k8s-debugkit repository overview

⁠k8s-debugkit

All-in-one docker image for debugging on Kubernetes and Docker

Note: Insecure, only for debugging

⁠:soon: Use cases

kubectl create deploy --image=amaya382/k8s-debugkit debugkit
kubectl expose --port=80 --type={type you need} deploy debugkit

or

kubectl apply -f k8s-debugkit.yaml # Default svc type: NodePort

And then, access to the debugkit via k8s Service, kubectl port-forward, or IP addr directly (Need specific env such as microk8s or telepresence)

⁠(1) Want to know which global ip is used

wget http://{debugkit's ip addr}/info/ip

{
  "globalIp": "XXX.XXX.XXX.XXX",
  "ip": [
    "1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000",
    "    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00",
    "    inet 127.0.0.1/8 scope host lo",
    "       valid_lft forever preferred_lft forever",
    "    inet6 ::1/128 scope host ",
    "       valid_lft forever preferred_lft forever",
    "3: eth0@if42: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default ",
    "    link/ether 92:8b:f7:b2:9f:df brd ff:ff:ff:ff:ff:ff link-netnsid 0",
    "    inet 10.1.1.16/24 scope global eth0",
    "       valid_lft forever preferred_lft forever",
    "    inet6 fe80::908b:f7ff:feb2:9fdf/64 scope link ",
    "       valid_lft forever preferred_lft forever"
  ]
}

A global ip k8s environment uses by default is XXX.XXX.XXX.XXX

⁠(2) Want to know which pod you're actually accessing (Good for accessing via a load balancer)

wget http://{debugkit's ip addr}/info/hostname

{
  "hostname": "debugkit-798cb977b-zjvfz"
}

hostname means pod name on k8s

⁠(3) Want to check if the default name server is working or not

wget http://{debugkit's ip addr}/exec/dig/google.com

{
  "dig": [
    "; <<>> DiG 9.10.3-P4-Debian <<>> google.com",
    ";; global options: +cmd",
    ";; Got answer:",
    ";; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29948",
    ";; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1",
    "",
    ";; OPT PSEUDOSECTION:",
    "; EDNS: version: 0, flags:; udp: 512",
    ";; QUESTION SECTION:",
    ";google.com.\t\t\tIN\tA",
    "",
    ";; ANSWER SECTION:",
    "google.com.\t\t185\tIN\tA\t172.217.26.46",
    "",
    ";; Query time: 40 msec",
    ";; SERVER: 10.152.183.10#53(10.152.183.10)",
    ";; WHEN: Mon May 06 07:42:12 UTC 2019",
    ";; MSG SIZE  rcvd: 55"
  ],
  "hostname": {
    "hostname": "debugkit-798cb977b-zjvfz"
  }
}

Working! Succeeded in resolving google.com

⁠:trident: Features

⁠HTTP Server

k8s-debugkit provides a HTTP server returning information and executing some commands from pod (container). You can check a lot of pod information by using just HTTP GET.

⁠Information

⁠/info/all

Get all information

⁠/info/commmon

Get common info based on request context

⁠/info/hostname

Get hostname. hostname in container means container id or pod name on k8s.

⁠/info/ip

Get local nic info and global ip

⁠/info/cpu

Get the number of cpus

⁠/info/mem

Get the amount of available memory

⁠/info/hosts

Get /etc/hosts

⁠/info/resolv

Get /etc/resolv.conf

⁠/info/envs

Get all environmental values

⁠Command execution

You can execute commands (from container!) via HTTP GET

⁠/exec/ping/{dst}

ping to dst

⁠/exec/dig/{dst}

Resolve name by default name server

⁠/exec/traceroute/{dst}

traceroute to dst

⁠/exec/get/{dst}

Exec a http get request to dst

⁠/exec/ls/{path}

List files

⁠/exec/cat/{path}

Get file contents

⁠/exec/getenv/{name}

Get an environmental value by name

⁠/exec/log/{msg}?{stderr}

Print log to stdout. If set stderr, output to stderr.

• stderr: Default False

⁠/exec/explode?{signal}&{explode_after}

Explode the container by signal after explode_after

• signal: Default 9
• explode_after: Default 5

⁠/exec/echo/<dst>

echo POST data

⁠CLI Tools

You can directly use the CLI tools below on container by kubectl exec -it {pod_name} bash or docker exec -it {container_name} bash

• kubectl
  • You need pass auth info such as .kube/config. e.g. kubectl cp ~/.kube/config {pod_name}:~/.kube/config
• ping
• curl
• wget
• dig
• nslookup
• traceroute

⁠Options

• K8S_DEBUGKIT_DISABLE_DEBUG_MODE
  • If set, run in production mode