compile-readflag.yaml

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: ds-readflag
  labels:
    app: build-readflag
spec:
  selector:
    matchLabels:
      app: build-readflag
  template:
    metadata:
      labels:
        app: build-readflag
    spec:
      hostNetwork: false
      restartPolicy: Always
      containers:
      - name: sleep
        image: muslcc/x86_64:x86_64-linux-musl
        command: [ "/bin/sh", "-c", "--" ]
        args: [ "while true; do sleep 30; done;" ]
        volumeMounts:
        - name: host-root
          mountPath: /host
          readOnly: false
        lifecycle:
          preStop:
            exec:
              command: ["rm", "-f", "/host/readflag"]
      initContainers:
      - name: build
        image: muslcc/x86_64:x86_64-linux-musl
        env:
        - name: FLAG
          value: "flag{test1234}"
        command: ["/bin/sh", "-c"]
        args:
          - |
            echo '#include <stdio.h>
            int main(){puts("'"$FLAG"'");}' > readflag.c && \
            gcc readflag.c -o /host/readflag -static -Os -s -Wl,--build-id=none -ffunction-sections -fdata-sections -Wl,--gc-sections && \
            rm readflag.c && \
            chmod 0111 /host/readflag
        volumeMounts:
        - name: host-root
          mountPath: /host
        securityContext:
          runAsUser: 0
      volumes:
      - name: host-root
        hostPath:
          path: /etc
          type: Directory
      terminationGracePeriodSeconds: 30