SYNOPSIS

       runc spec [command options] [arguments...]

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" program.

EXAMPLE

       To  run  docker's hello-world container one needs to set the args parameter in the spec to
       call hello. This can be done using the  sed  command  or  a  text  editor.  The  following
       commands  create  a  bundle for hello-world, change the default args parameter in the spec
       from "sh" to "/hello", then 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
              sed -i 's;"sh";"/hello";' config.json
              runc start container1

       In  the  start  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", the
       sub-command "oci-runtime-tool generate" has lots of options that can be  used  to  do  any
       customizations  as  you want, see ⟨https://github.com/opencontainers/runtime-tools⟩ to get
       more information.

       When starting a container through runc, runc needs root privilege. If not already  running
       as  root,  you  can  use  sudo  to give runc root privilege. For example: "sudo runc start
       container1" will give runc root privilege to start the container on your host.

       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 parameter --rootless to this command to  generate  a  proper
       rootless spec file.

OPTIONS

       --bundle value, -b value     path to the root of the bundle directory
          --rootless                   generate a configuration for a rootless container

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