cexec

quay.io/tinkerbell/actions/cexec:latest

The cexec Action performs execution either within a chroot environment or within the base filesystem. The primary use-case is being able to provision files/an Operating System to disk and then being able to execute something that perhaps resides within that filesystem.

Examples

actions:
- name: "Install Grub"
  image: quay.io/tinkerbell/actions/cexec:latest
  timeout: 90
  environment:
      BLOCK_DEVICE: /dev/sda3
      FS_TYPE: ext4
      CHROOT: y
      CMD_LINE: "grub-install --root-directory=/boot /dev/sda"

In order to execute multiple commands (separated by a semi-colon) we will need to leverage a shell. We do this by passing sh -c as a DEFAULT_INTERPRETER. This interpreter will then parse your commands.

actions:
- name: "Update packages"
  image: quay.io/tinkerbell/actions/cexec:latest
  timeout: 90
  environment:
      BLOCK_DEVICE: /dev/sda3
      FS_TYPE: ext4
      CHROOT: y
      DEFAULT_INTERPRETER: "/bin/sh -c"
      CMD_LINE: "apt-get -y update; apt-get -y upgrade"
      UPDATE_RESOLV_CONF: true
      DEBIAN_FRONTEND: noninteractive

Environment variables and CLI flags

All options can be set either via environment variables or CLI flags. CLI flags take precedence over environment variables, which take precedence over default values.

Env variable	Flag	Type	Default Value	Required	Description
BLOCK_DEVICE	--block-device	string	""	yes	The block device to mount.
FS_TYPE	--fs-type	string	""	yes	The filesystem type of the block device.
CHROOT	--chroot	string	""	no	If set to y (or a non empty string), the Action will execute the given command within a chroot environment. This option is DEPRECATED. Future versions will always chroot.
CMD_LINE	--cmd-line	string	""	yes	The command to execute.
DEFAULT_INTERPRETER	--default-interpreter	string	""	no	The default interpreter to use when executing commands. This is useful when you need to execute multiple commands.
UPDATE_RESOLV_CONF	--update-resolv-conf	boolean	false	no	If set to true, the cexec Action will update the /etc/resolv.conf file within the chroot environment with the /etc/resolv.conf from the host.
JSON_OUTPUT	--json-output	boolean	true	no	If set to true, the cexec Action will log output in JSON format. The defaults to true. If set to false, the cexec Action will log output in plain text format.

Any environment variables you set on the Action will be available to the command you execute. For example, if you set DEBIAN_FRONTEND: noninteractive as an environment variable, it will be available to the command you execute.

Exit codes

The following exit codes or statuses are returned by the cexec Action:

Code	Description
0	The cexec Action was executed successfully.
10	The was a failure parsing cli flags and/or env variables.
20	Required cli flags and/or env variables were not specified.
30	The cexec Action failed to execute successfully.