runc-spec(8)		    System Manager's Manual		  runc-spec(8)



NAME
       runc-spec - create a new specification file



SYNOPSIS
       runc spec [option ...]



DESCRIPTION
       The spec command creates the new specification file named config.json
       for the bundle.


       The spec generated is just a starter file. Editing of the spec is
       required to achieve desired results. For example, the newly generated
       spec includes an args parameter that is initially set to call the sh
       command when the container is started. Calling sh may work for an
       ubuntu container or busybox, but will not work for containers that do
       not include the sh binary.



OPTIONS
       --bundle|-b path
	      Set path to the root of the bundle directory.


       --rootless
	      Generate a configuration for a rootless container. Note this
	      option is entirely different from the global --rootless option.



EXAMPLES
       To run a simple "hello-world" container, one needs to set the args
       parameter in the spec to call hello. This can be done using sed(1),
       jq(1), or a text editor.


       The following commands will:
	- create a bundle for hello-world;
	- change the command to run in a container to /hello using jq(1);
	- run the hello command in a new hello-world container named
       container1.

       mkdir hello
       cd hello
       docker pull hello-world
       docker export $(docker create hello-world) > hello-world.tar
       mkdir rootfs
       tar -C rootfs -xf hello-world.tar
       runc spec
       jq '.process.args |= ["/hello"]' < config.json > new.json
       mv -f new.json config.json
       runc run container1


       In the run command above, container1 is the name for the instance of
       the container that you are starting. The name you provide for the
       container instance must be unique on your host.


       An alternative for generating a customized spec config is to use oci-
       runtime-tool; its sub-command oci-runtime-tool generate has lots of
       options that can be used to do any customizations as you want. See
       runtime-tools ⟨https://github.com/opencontainers/runtime-tools⟩ to get
       more information.


       When starting a container through runc, the latter usually needs root
       privileges. If not already running as root, you can use sudo(8), for
       example:

       sudo runc start container1


       Alternatively, you can start a rootless container, which has the
       ability to run without root privileges.	For this to work, the
       specification file needs to be adjusted accordingly.  You can pass the
       --rootless option to this command to generate a proper rootless spec
       file.



SEE ALSO
       runc-run(8), runc(8).

								  runc-spec(8)