overlay.hpp

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#ifndef __MESOS_PROVISIONER_OVERLAY_HPP__
#define __MESOS_PROVISIONER_OVERLAY_HPP__

#include <list>
#include <string>

#include "slave/containerizer/mesos/provisioner/backend.hpp"

namespace mesos {
namespace internal {
namespace slave {

// Forward declaration.
class OverlayBackendProcess;


// This backend mounts the images layers to the rootfs using the overlay file
// system. The directory layout is as follows:
// <work_dir> ('--work_dir' flag)
// |-- provisioner
//     |-- containers
//         |-- <container-id>
//             |-- backends
//                 |-- overlay
//                    |-- rootfses
//                        |-- <rootfs_id> (the rootfs)
//                    |-- scratch
//                        |-- <rootfs_id> (the scratch space)
//                            |-- upperdir
//                            |-- workdir
//                            |-- links (symlink to temp dir with links to layers) // NOLINT(whitespace/line_length)
class OverlayBackend : public Backend
{
public:
  ~OverlayBackend() override;

  static Try<process::Owned<Backend>> create(const Flags&);

  static Try<std::list<std::string>> listEphemeralVolumes(
      const std::string& workDir);

  process::Future<Option<std::vector<Path>>> provision(
      const std::vector<std::string>& layers,
      const std::string& rootfs,
      const std::string& backendDir) override;

  process::Future<bool> destroy(
      const std::string& rootfs,
      const std::string& backendDir) override;

private:
  explicit OverlayBackend(process::Owned<OverlayBackendProcess> process);

  OverlayBackend(const OverlayBackend&);
  OverlayBackend& operator=(const OverlayBackend&);

  process::Owned<OverlayBackendProcess> process;
};

} // namespace slave {
} // namespace internal {
} // namespace mesos {

#endif // __MESOS_PROVISIONER_OVERLAY_HPP__