Concurrent code application in a stateful computing environment

A method comprising:

• initializing, by a master process executed by a processor coupled to a memory, an environment for operating an application process;
• starting, by the master process, an execution of the application process within the environment;
• upgrading, by the master process, a code of the application process while the master process maintains network connectivity between the environment and the execution of the application process, wherein the network connectivity exists in a socket domain, wherein the master process opens one or more network sockets and keeps socket file descriptors on behalf of the application process, wherein the application process does not open the one or more network sockets, wherein the one or more network sockets comprises a control socket for exchanging control messages with the application process and a data socket for transmitting data;
• detecting, by the master process, a catastrophic error with the application process, wherein the detection is performed by polling variables to determine the catastrophic error;
• and
• restarting, by the master process, the application process in response to the detection of the catastrophic error while maintaining socket connection to the application process.