Controlling user access to command execution

A computer-implemented method comprising:

• performing, by a shell aggregator executing on one or more computing systems:
• receiving a request from a user to execute a command by a plurality of computing nodes provided for the user by a network-accessible service;
• determining, based at least in part on permissions information stored externally to the plurality of computing nodes, that the user is authorized to execute the command on a first computing node of the plurality of computing nodes but not authorized to execute the command on a second computing node of the plurality of computing nodes;
• and
• in response to the determining:
• causing the first computing node to execute the command;
• and
• denying execution of the command by the second computing node.

One or more non-transitory computer-readable media having stored instructions that when executed on or across one or more processors cause the one or more processors to implement a shell aggregator and to:

• receive a request from a user to execute a command by a plurality of computing nodes provided for the user by a network-accessible service;
• determine, based at least in part on permissions information stored externally to the plurality of computing nodes, that the user is authorized to execute the command on a first computing node of the plurality of computing nodes but not authorized to execute the command on a second computing node of the plurality of computing nodes;
• and
• in response to the determining:
• cause the first computing node to execute the command;
• and
• deny execution of the command by the second computing node.