Method and system for providing coordinated checkpointing to a group of independent computer applications

A method, comprising:

• migrating without loss an application group comprising one or more independent applications each executing on a primary node from the respective primary nodes of the one or more independent applications to at least one backup node;
• installing interceptors for fork( ) and exec( );
• preloading a custom_init( ) function;
• maintaining transparency to a client connected to an independent application on a primary node over a transport connection;
• restoring the application group, including all of the independent applications, from checkpoints in response to initiating recovery of the application group;
• upon issuing an exec( ) call by an independent application, passing control of the independent application to the interceptors, calling, by the interceptors, an operating system exec( ), overlaying a new image onto an existing independent application process, using an environment variable to preserve across exec( ) a number of times a process has exec'ed, and running said interceptors for fork( ) and exec( ) in user-space;
• and
• calling an independent application's entry point to run the independent application;
• wherein said one or more independent applications can use both fork( ) and exec( );
• wherein said checkpoints store in a shared memory at least one of a global application state including checkpoint barrier information having a barrier semaphore ID, a Virtual PID table, a Pipe table, a Semaphore ID table, and a “SystemV shared memory segment ID” table;
• and
• wherein the shared memory is configured to be outside an address space of the independent applications.

A method, comprising:

• installing interceptors for fork( ) and exec( );
• preloading a custom_init( ) function;
• loading and running an independent application wherein said independent application is a member of an application group comprised of one or more independent applications;
• upon the application issuing a fork call, passing control of the application to the interceptors;
• calling, by the interceptors, an operating system fork( ), creating a new application process from a parent process, passing control of the application back to the interceptors;
• and upon the application issuing an exec call, passing control of the application to the interceptors;
• calling, by the interceptors, an operating system exec( ) overlaying a new application image onto said new application process, passing control of the application back to the interceptors, and running said interceptors for fork( ) and exec( ) in user-space;
• calling an application's entry point to run the application;
• and
• storing in a shared memory at least one of a global application state including checkpoint barrier information having a barrier semaphore ID, a Virtual PID table, a Pipe table, a Semaphore ID table, and a “SystemV shared memory segment ID” table;
• wherein the shared memory is configured to be outside an address space of the independent application.

A method, comprising:

• preloading a custom_init( ) function;
• loading an independent application;
• installing interceptors for fork( ) and exec( );
• storing in shared memory at least one of a global application state including checkpoint barrier information having a barrier semaphore ID, a Virtual PID table, a Pipe table, a Semaphore ID table, and a “System V shared memory segment ID” table;
• and
• calling the independent application's entry point to run the independent application;
• upon the application issuing an exec call, passing control of the application to the interceptors, calling, by the interceptors, an operating system exec( ), overlaying a new application image onto an existing application process, and running said interceptors for fork( ) and exec( ) in user-space;
• wherein the shared memory is configured to be outside an address space of the independent application.

A method, comprising:

• installing interceptors for fork( ) and exec( );
• initializing a new image, restoring all internal state from shared memory, and executing the new image;
• storing in a shared memory at least one of a global application state including checkpoint barrier information having a barrier semaphore ID, a Virtual PID table, a Pipe table, a Semaphore ID table, and a “SystemV shared memory segment ID” table;
• and
• upon issuing an exec call by an independent application, passing control of the application to the interceptors, calling, by the interceptors, an operating system exec( ) overlaying a new image onto an existing application process, and using an environment variable to preserve across exec( ) a number of times a process has exec'ed;
• wherein the shared memory is configured to be outside an address space of the independent application.

A method, comprising:

• installing interceptors for fork( ) and exec( );
• initializing an application image, restoring all internal state from a first shared memory, and executing the application image;
• storing in a second shared memory at least one of a global application state including checkpoint barrier information having a barrier semaphore ID, a Virtual PID table, a Pipe table, a Semaphore ID table, and a “System V shared memory segment ID” table;
• and
• upon an application issuing an exec call, passing control of the application to the interceptors, calling, by the interceptors, an operating system exec( ), overlaying a new image onto an existing application process, and using an environment variable to preserve, across exec, a number of times a process must exec prior to restoring its data;
• wherein said first and second shared memory are configured to be outside an address space of the application;
• and
• wherein said interceptors for fork( ) and exec( ) are configured to operate user-space.