Diagnostic code

ZBX-E0221

can't join the running container

Kind

error

Blame

environment

Exit code

2 (125 in zbx exec)

What it means

zbx exec reads the container's environment from its first process, opens its namespaces (/proc/<pid>/ns), and in a child joins them with setns: the user namespace first (zbx made it, so this needs no privilege), then the IPC, UTS, network, PID and mount namespaces, and forks the command into the PID namespace. One of these was refused.

The cause names the step and the kernel's reason. A container that ended at that moment is the usual one (try again: zbx ps shows it). A security policy that forbids setns, or a /proc that hides other processes (hidepid), is the other. Nothing was started.

Offline

The same text, without a network:

zbx explain E0221