Persistent State Partition


RancherOS will store its state in a single partition specified by the dev field. The field can be a device such as /dev/sda1 or a logical name such LABEL=state or UUID=123124. The default value is LABEL=RANCHER_STATE. The file system type of that partition can be set to auto or a specific file system type such as ext4.

#cloud-config
rancher:
  state:
    fstype: auto
    dev: LABEL=RANCHER_STATE
    autoformat:
    - /dev/sda
    - /dev/vda

Autoformat

You can specify a list of devices to check to format on boot. If the state partition is already found, RancherOS will not try to auto format a partition. By default, auto-formatting is off.

RancherOS will autoformat the partition to ext4 if the device specified in autoformat:

  • Contains a boot2docker magic string
  • Starts with 1 megabyte of zeros and rancher.state.formatzero is true