RancherOS 1.5.6 inject ssh keys into cloud-config.yml

RancherOS
1

When I reboot the RancherOS (version 1.5.6) instance it injects some ssh keys into cloud-config.yml. I have deleted it several times , but it appears each time. It looks very strange, like some type of backdoor issue. Does anybody know what is it and how to disable it?

rancher:
  ssh:
    keys:
      dsa: |+
        -----BEGIN OPENSSH PRIVATE KEY-----
        b3Blbn ... AUG
        -----END OPENSSH PRIVATE KEY-----
      dsa-pub: |+
        ssh-dss AAAA ... BrH
      ecdsa: |+
        -----BEGIN OPENSSH PRIVATE KEY-----
        b3BlbnN ... A==
        -----END OPENSSH PRIVATE KEY-----
      ecdsa-pub: |+
        ecdsa-sha2-nistp256 AAAA ... GUp
      ed25519: |+
        -----BEGIN OPENSSH PRIVATE KEY-----
        b3Blbn ... gE=
        -----END OPENSSH PRIVATE KEY-----
      ed25519-pub: |+
        ssh-ed25519 AAAA ... oT root@rancher
      rsa: |+
        -----BEGIN OPENSSH PRIVATE KEY-----
        b3Blbn ... g==
        -----END OPENSSH PRIVATE KEY-----
      rsa-pub: |+
        ssh-rsa AAAA ... u8W3