Debug-Container

This container can be thought of as the administrator’s shell. Many of the debugging tools (such as ping, traceroute, and mtr) and man pages that an administrator might use to diagnose problems on the host are in this container.

• Networking-related commands:
  • iproute
  • net-tools
  • mtr
  • dig
  • ping
  • ethtool
  • nmap-ncat
• Generic commands:
  • vim
  • git
  • htop

Download

docker pull ghcr.io/pichuang/debug-container:master

How to use debug-container on specific hosts?

1. Bridge Mode (Container on OS):

docker run -it --rm --name debug-container ghcr.io/pichuang/debug-container:master

2. Host Mode (Container within OS):

docker run -it --rm --name debug --privileged \
       --ipc=host --net=host --pid=host -e HOST=/host \
       -e NAME=debug-container -e IMAGE=pichuang/debug-container \
       -v /run:/run -v /var/log:/var/log \
       -v /etc/localtime:/etc/localtime -v /:/host \
       ghcr.io/pichuang/debug-container:master

3. Container Mode (Bridge another container)

docker run -it --rm --name debug-contaienr --net container:<container_name> ghcr.io/pichuang/debug-container:master

How to use debug-container on Native Kubernetes/Tanzu Kubernetes Grid Cluster/Azure Kubernetes Service?

1. Namespace Level Debugging: Running one Pod in namespace and any node

kubectl run -n default debug-container --restart=Never --rm -i --tty --image ghcr.io/pichuang/debug-container:master -- /bin/bash

2. Namespace Level Debugging: Running one Pod in namespace and specific node

# Show all of nodes
kubectl get nodes
NAME                                STATUS   ROLES   AGE   VERSION
aks-agentpool-40137516-vmss000000   Ready    agent   82m   v1.22.11
aks-agentpool-40137516-vmss000001   Ready    agent   82m   v1.22.11
aks-agentpool-40137516-vmss000002   Ready    agent   82m   v1.22.11

# Run the command
kubectl run -n default debug-container --restart=Never --rm -i --tty --overrides='{ "apiVersion": "v1", "spec": {"kubernetes.io/hostname":"aks-agentpool-40137516-vmss000002"}}' --image ghcr.io/pichuang/debug-container:master -- /bin/bash

3. Node Level Debugging: Running one Pod on specific node

kubectl run -n default debug-container --image ghcr.io/pichuang/debug-container:master \
  --restart=Never -it --attach --rm \
  --overrides='{ "apiVersion": "v1", "spec": { "nodeSelector":{"kubernetes.io/hostname":"aks-agentpool-40137516-vmss000002"}, "hostNetwork": true}}' -- /bin/bash

# or
$ kubectl debug node/aks-agentpool-40137516-vmss000002 -it --image=ghcr.io/pichuang/debug-container:master -- /bin/bash
Creating debugging pod node-debugger-aks-agentpool-40137516-vmss000002-psvms with container debugger on node aks-agentpool-40137516-vmss000002.
If you don't see a command prompt, try pressing enter.

[root@aks-agentpool-14864487-vmss000000 /]# chroot /host /bin/bash
root [ / ]# cat /etc/os-release | head -n 2

How to use debug-container on Red Hat OpenShift?

1. Namespace Level Debugging: Running one Pod in project and any node

oc project <PROJECT NAME>
oc run ocp-debug-container --image ghcr.io/pichuang/debug-container:master \
   --restart=Never --attach -i --tty --rm

2. Namespace Level Debugging: Running one Pod in project and specific node

oc project <PROJECT NAME>
oc run ocp-debug-container --image ghcr.io/pichuang/debug-container:master \
   --restart=Never --attach -i --tty --rm \
   --overrides='{ "apiVersion": "v1", "spec": { "kubernetes.io/hostname":"compute-1"}}}'

• Remind: Please replace kubernetes.io/hostname:<hostname>

3. Node Level Debugging: Running one Pod on specific node

oc project <PROJECT NAME>
oc run ocp-debug-container --image ghcr.io/pichuang/debug-container:master \
  --restart=Never -it --attach --rm \
  --overrides='{ "apiVersion": "v1", "spec": { "nodeSelector":{"kubernetes.io/hostname":"compute-1"}, "hostNetwork": true}}'

4. Running Container Level Debugging

oc project <PROJECT NAME>
oc rsh pod/<PDO NAME>

5. Running Pods Level Debugging

oc project <PROJECT NAME>
oc debug pods/<Pod NAME>

How to Import YAML?

---
apiVersion: v1
kind: Pod
metadata:
  name: ocp-debug-container
spec:
  containers:
  - image: ghcr.io/pichuang/debug-container:master
    name: ocp-debug-container
    command: [ "/bin/bash", "-c", "--" ]
    args: [ "while true; do sleep 30; done;" ]

How to build the container images?

• If you choose buildah...

make build-buildah

• If you choose docker...

make build-docker

Author

• Phil Huang phil.huang@microsoft.com