Critical error codes for DevOps engineers — Linux, Docker, Nginx, cloud providers, and database errors.
Akousa502A gateway or proxy server received an invalid response from the upstream server.
503The server is temporarily unable to handle the request due to maintenance or overloading.
504A gateway or proxy server did not receive a timely response from the upstream server.
ENOSPCThe filesystem has no more free space or inodes available for writing.
ENOMEMThe system does not have enough available memory to fulfill the allocation request.
EMFILEThe per-process limit on the number of open file descriptors has been reached.
EACCESThe requested access to a file or resource is not allowed by the file permissions.
SIGKILL (9)The process was unconditionally terminated. This signal cannot be caught, blocked, or ignored.
SIGTERM (15)A graceful termination request was sent to the process.
Exit Code 1The container process exited with a general error.
Exit Code 137The container was killed with SIGKILL (signal 9), commonly due to out-of-memory (OOM) conditions.
Exit Code 139The container crashed with a segmentation fault (SIGSEGV, signal 11).
Exit Code 143The container was terminated gracefully with SIGTERM (signal 15).
502 Bad GatewayNginx received an invalid response from the upstream server.
504 Gateway TimeoutNginx timed out waiting for a response from the upstream server.
upstream timed outNginx timed out while waiting for the upstream server to respond.
worker_connections are not enoughThe Nginx worker process has reached its maximum number of connections.
08001The client could not establish a connection to the database server.
40001The transaction was rolled back due to a serialization conflict.
40P01Two or more transactions are waiting for each other's locks, creating a deadlock.
ERR_CONNECTION_TIMED_OUTThe browser's connection attempt timed out waiting for a server response.
DNS_TIMEOUTThe DNS query timed out without receiving a response.
ThrottlingExceptionThe request was throttled due to exceeding the API rate limit.
ServiceUnavailableExceptionThe AWS service is temporarily unavailable.